* [PATCH v18 20/42] dept: apply timeout consideration to dma fence wait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Now that CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT was introduced, apply the
consideration to dma fence wait.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
drivers/dma-buf/dma-fence.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index b313bb59dc9c..f2cc7068af65 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -799,7 +799,7 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
cb.task = current;
list_add(&cb.base.node, &fence->cb_list);
- sdt_might_sleep_start(NULL);
+ sdt_might_sleep_start_timeout(NULL, timeout);
while (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) && ret > 0) {
if (intr)
__set_current_state(TASK_INTERRUPTIBLE);
@@ -903,7 +903,7 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count,
}
}
- sdt_might_sleep_start(NULL);
+ sdt_might_sleep_start_timeout(NULL, timeout);
while (ret > 0) {
if (intr)
set_current_state(TASK_INTERRUPTIBLE);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 21/42] dept: make dept able to work with an external wgen
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
There is a case where the total map size of waits of a class is so large.
For instance, PG_locked is the case if every struct page embeds its
regular map for PG_locked. The total size for the maps will be 'the #
of pages * sizeof(struct dept_map)', which is too big to accept.
Keep the minimum data in the case, timestamp called 'wgen', that dept
uses. Make dept able to work with the wgen instead of whole regular map.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/dept.h | 18 ++++++++++++++----
include/linux/dept_sdt.h | 6 +++---
kernel/dependency/dept.c | 30 +++++++++++++++++++++---------
3 files changed, 38 insertions(+), 16 deletions(-)
diff --git a/include/linux/dept.h b/include/linux/dept.h
index e70cbc6f41dc..7d5e01f56e8e 100644
--- a/include/linux/dept.h
+++ b/include/linux/dept.h
@@ -129,6 +129,13 @@ struct dept_wait_hist {
unsigned int ctxt_id;
};
+/*
+ * for subsystems that requires compact use of memory e.g. struct page
+ */
+struct dept_ext_wgen {
+ unsigned int wgen;
+};
+
extern void dept_on(void);
extern void dept_off(void);
extern void dept_init(void);
@@ -138,6 +145,7 @@ extern void dept_free_range(void *start, unsigned int sz);
extern void dept_map_init(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
extern void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
+extern void dept_ext_wgen_init(struct dept_ext_wgen *ewg);
extern void dept_map_copy(struct dept_map *to, struct dept_map *from);
extern void dept_wait(struct dept_map *m, unsigned long w_f, unsigned long ip, const char *w_fn, int sub_l, long timeout);
extern void dept_stage_wait(struct dept_map *m, struct dept_key *k, unsigned long ip, const char *w_fn, long timeout);
@@ -146,8 +154,8 @@ extern void dept_clean_stage(void);
extern void dept_ttwu_stage_wait(struct task_struct *t, unsigned long ip);
extern void dept_ecxt_enter(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *c_fn, const char *e_fn, int sub_l);
extern bool dept_ecxt_holding(struct dept_map *m, unsigned long e_f);
-extern void dept_request_event(struct dept_map *m);
-extern void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *e_fn);
+extern void dept_request_event(struct dept_map *m, struct dept_ext_wgen *ewg);
+extern void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *e_fn, struct dept_ext_wgen *ewg);
extern void dept_ecxt_exit(struct dept_map *m, unsigned long e_f, unsigned long ip);
extern void dept_sched_enter(void);
extern void dept_sched_exit(void);
@@ -174,6 +182,7 @@ extern void dept_hardirqs_off(void);
#else /* !CONFIG_DEPT */
struct dept_key { };
struct dept_map { };
+struct dept_ext_wgen { };
#define DEPT_MAP_INITIALIZER(n, k) { }
@@ -186,6 +195,7 @@ struct dept_map { };
#define dept_map_init(m, k, su, n) do { (void)(n); (void)(k); } while (0)
#define dept_map_reinit(m, k, su, n) do { (void)(n); (void)(k); } while (0)
+#define dept_ext_wgen_init(wg) do { } while (0)
#define dept_map_copy(t, f) do { } while (0)
#define dept_wait(m, w_f, ip, w_fn, sl, t) do { (void)(w_fn); } while (0)
#define dept_stage_wait(m, k, ip, w_fn, t) do { (void)(k); (void)(w_fn); } while (0)
@@ -194,8 +204,8 @@ struct dept_map { };
#define dept_ttwu_stage_wait(t, ip) do { } while (0)
#define dept_ecxt_enter(m, e_f, ip, c_fn, e_fn, sl) do { (void)(c_fn); (void)(e_fn); } while (0)
#define dept_ecxt_holding(m, e_f) false
-#define dept_request_event(m) do { } while (0)
-#define dept_event(m, e_f, ip, e_fn) do { (void)(e_fn); } while (0)
+#define dept_request_event(m, wg) do { } while (0)
+#define dept_event(m, e_f, ip, e_fn, wg) do { (void)(e_fn); } while (0)
#define dept_ecxt_exit(m, e_f, ip) do { } while (0)
#define dept_sched_enter() do { } while (0)
#define dept_sched_exit() do { } while (0)
diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h
index 14917df0cc30..9cd70affaf35 100644
--- a/include/linux/dept_sdt.h
+++ b/include/linux/dept_sdt.h
@@ -25,7 +25,7 @@
#define sdt_wait_timeout(m, t) \
do { \
- dept_request_event(m); \
+ dept_request_event(m, NULL); \
dept_wait(m, 1UL, _THIS_IP_, __func__, 0, t); \
} while (0)
#define sdt_wait(m) sdt_wait_timeout(m, -1L)
@@ -49,9 +49,9 @@
#define sdt_might_sleep_end() dept_clean_stage()
#define sdt_ecxt_enter(m) dept_ecxt_enter(m, 1UL, _THIS_IP_, "start", "event", 0)
-#define sdt_event(m) dept_event(m, 1UL, _THIS_IP_, __func__)
+#define sdt_event(m) dept_event(m, 1UL, _THIS_IP_, __func__, NULL)
#define sdt_ecxt_exit(m) dept_ecxt_exit(m, 1UL, _THIS_IP_)
-#define sdt_request_event(m) dept_request_event(m)
+#define sdt_request_event(m) dept_request_event(m, NULL)
#else /* !CONFIG_DEPT */
#define sdt_map_init(m) do { } while (0)
#define sdt_map_init_key(m, k) do { (void)(k); } while (0)
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index 519b2151403e..f928c12111fe 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -2172,6 +2172,11 @@ void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u,
}
EXPORT_SYMBOL_GPL(dept_map_reinit);
+void dept_ext_wgen_init(struct dept_ext_wgen *ewg)
+{
+ ewg->wgen = 0U;
+}
+
void dept_map_copy(struct dept_map *to, struct dept_map *from)
{
if (unlikely(!dept_working())) {
@@ -2355,7 +2360,7 @@ static void __dept_wait(struct dept_map *m, unsigned long w_f,
*/
static void __dept_event(struct dept_map *m, struct dept_map *real_m,
unsigned long e_f, unsigned long ip, const char *e_fn,
- bool sched_map)
+ bool sched_map, unsigned int wg)
{
struct dept_class *c;
struct dept_key *k;
@@ -2377,7 +2382,7 @@ static void __dept_event(struct dept_map *m, struct dept_map *real_m,
c = check_new_class(&m->map_key, k, sub_id(m, e), m->name, sched_map);
if (c)
- do_event(m, real_m, c, READ_ONCE(m->wgen), ip, e_fn);
+ do_event(m, real_m, c, wg, ip, e_fn);
}
void dept_wait(struct dept_map *m, unsigned long w_f,
@@ -2602,7 +2607,7 @@ void dept_ttwu_stage_wait(struct task_struct *requestor, unsigned long ip)
if (!m.keys)
goto exit;
- __dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map);
+ __dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map, m.wgen);
exit:
dept_exit(flags);
}
@@ -2781,10 +2786,11 @@ bool dept_ecxt_holding(struct dept_map *m, unsigned long e_f)
}
EXPORT_SYMBOL_GPL(dept_ecxt_holding);
-void dept_request_event(struct dept_map *m)
+void dept_request_event(struct dept_map *m, struct dept_ext_wgen *ewg)
{
unsigned long flags;
unsigned int wg;
+ unsigned int *wg_p;
if (unlikely(!dept_working()))
return;
@@ -2797,18 +2803,22 @@ void dept_request_event(struct dept_map *m)
*/
flags = dept_enter_recursive();
+ wg_p = ewg ? &ewg->wgen : &m->wgen;
+
wg = next_wgen();
- WRITE_ONCE(m->wgen, wg);
+ WRITE_ONCE(*wg_p, wg);
dept_exit_recursive(flags);
}
EXPORT_SYMBOL_GPL(dept_request_event);
void dept_event(struct dept_map *m, unsigned long e_f,
- unsigned long ip, const char *e_fn)
+ unsigned long ip, const char *e_fn,
+ struct dept_ext_wgen *ewg)
{
struct dept_task *dt = dept_task();
unsigned long flags;
+ unsigned int *wg_p;
if (unlikely(!dept_working()))
return;
@@ -2816,24 +2826,26 @@ void dept_event(struct dept_map *m, unsigned long e_f,
if (m->nocheck)
return;
+ wg_p = ewg ? &ewg->wgen : &m->wgen;
+
if (dt->recursive) {
/*
* Dept won't work with this even though an event
* context has been asked. Don't make it confused at
* handling the event. Disable it until the next.
*/
- WRITE_ONCE(m->wgen, 0U);
+ WRITE_ONCE(*wg_p, 0U);
return;
}
flags = dept_enter();
- __dept_event(m, m, e_f, ip, e_fn, false);
+ __dept_event(m, m, e_f, ip, e_fn, false, READ_ONCE(*wg_p));
/*
* Keep the map diabled until the next sleep.
*/
- WRITE_ONCE(m->wgen, 0U);
+ WRITE_ONCE(*wg_p, 0U);
dept_exit(flags);
}
--
2.17.1
^ permalink raw reply related
* [PATCH v18 18/42] dept: apply timeout consideration to waitqueue wait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Now that CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT was introduced, apply the
consideration to waitqueue wait, assuming an input 'ret' in
___wait_event() macro is used as a timeout value.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/wait.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 7815caf61a15..60bed80198e2 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -306,7 +306,7 @@ extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
struct wait_queue_entry __wq_entry; \
long __ret = ret; /* explicit shadow */ \
\
- sdt_might_sleep_start(NULL); \
+ sdt_might_sleep_start_timeout(NULL, __ret); \
init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
for (;;) { \
long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
--
2.17.1
^ permalink raw reply related
* [PATCH v18 19/42] dept: apply timeout consideration to hashed-waitqueue wait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Now that CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT was introduced, apply the
consideration to hashed-waitqueue wait, assuming an input 'ret' in
___wait_var_event() macro is used as a timeout value.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/wait_bit.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h
index 179a616ad245..9885ac4e1ded 100644
--- a/include/linux/wait_bit.h
+++ b/include/linux/wait_bit.h
@@ -258,7 +258,7 @@ extern wait_queue_head_t *__var_waitqueue(void *p);
struct wait_bit_queue_entry __wbq_entry; \
long __ret = ret; /* explicit shadow */ \
\
- sdt_might_sleep_start(NULL); \
+ sdt_might_sleep_start_timeout(NULL, __ret); \
init_wait_var_entry(&__wbq_entry, var, \
exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
for (;;) { \
--
2.17.1
^ permalink raw reply related
* [PATCH v18 17/42] dept: apply timeout consideration to swait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Now that CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT was introduced, apply the
consideration to swait, assuming an input 'ret' in ___swait_event()
macro is used as a timeout value.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/swait.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/swait.h b/include/linux/swait.h
index 277ac74f61c3..233acdf55e9b 100644
--- a/include/linux/swait.h
+++ b/include/linux/swait.h
@@ -162,7 +162,7 @@ extern void finish_swait(struct swait_queue_head *q, struct swait_queue *wait);
struct swait_queue __wait; \
long __ret = ret; \
\
- sdt_might_sleep_start(NULL); \
+ sdt_might_sleep_start_timeout(NULL, __ret); \
INIT_LIST_HEAD(&__wait.task_list); \
for (;;) { \
long __int = prepare_to_swait_event(&wq, &__wait, state);\
--
2.17.1
^ permalink raw reply related
* [PATCH v18 16/42] dept: apply timeout consideration to wait_for_completion()/complete()
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Now that CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT was introduced, apply the
consideration to wait_for_completion()/complete().
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/completion.h | 4 ++--
kernel/sched/completion.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/completion.h b/include/linux/completion.h
index bd2c207481d6..3200b741de28 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -41,9 +41,9 @@ do { \
*/
#define init_completion_map(x, m) init_completion(x)
-static inline void complete_acquire(struct completion *x)
+static inline void complete_acquire(struct completion *x, long timeout)
{
- sdt_might_sleep_start(&x->dmap);
+ sdt_might_sleep_start_timeout(&x->dmap, timeout);
}
static inline void complete_release(struct completion *x)
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
index 19ee702273c0..5e45a60ff7b3 100644
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -115,7 +115,7 @@ __wait_for_common(struct completion *x,
{
might_sleep();
- complete_acquire(x);
+ complete_acquire(x, timeout);
raw_spin_lock_irq(&x->wait.lock);
timeout = do_wait_for_common(x, action, timeout, state);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 14/42] dept: apply sdt_might_sleep_{start,end}() to dma fence
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Make dept able to track dependencies by dma fence waits and signals.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
drivers/dma-buf/dma-fence.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index b4f5c8635276..b313bb59dc9c 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -16,6 +16,7 @@
#include <linux/dma-fence.h>
#include <linux/sched/signal.h>
#include <linux/seq_file.h>
+#include <linux/dept_sdt.h>
#define CREATE_TRACE_POINTS
#include <trace/events/dma_fence.h>
@@ -798,6 +799,7 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
cb.task = current;
list_add(&cb.base.node, &fence->cb_list);
+ sdt_might_sleep_start(NULL);
while (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) && ret > 0) {
if (intr)
__set_current_state(TASK_INTERRUPTIBLE);
@@ -811,6 +813,7 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
if (ret > 0 && intr && signal_pending(current))
ret = -ERESTARTSYS;
}
+ sdt_might_sleep_end();
if (!list_empty(&cb.base.node))
list_del(&cb.base.node);
@@ -900,6 +903,7 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count,
}
}
+ sdt_might_sleep_start(NULL);
while (ret > 0) {
if (intr)
set_current_state(TASK_INTERRUPTIBLE);
@@ -914,6 +918,7 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count,
if (ret > 0 && intr && signal_pending(current))
ret = -ERESTARTSYS;
}
+ sdt_might_sleep_end();
__set_current_state(TASK_RUNNING);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 15/42] dept: track timeout waits separately with a new Kconfig
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Waits with valid timeouts don't actually cause deadlocks. However, dept
has been reporting the cases as well because it's worth informing the
circular dependency for some cases where, for example, timeout is used
to avoid a deadlock.
However, yes, there are also a lot of, even more, cases where timeout
is used for its clear purpose and meant to be expired.
Report these as an information rather than warning DEADLOCK. Plus,
introduce CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT Kconfig to make it
optional so that any reports involving waits with timeouts can be turned
on/off depending on the purpose.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/dept.h | 8 ++--
include/linux/dept_ldt.h | 6 +--
include/linux/dept_sdt.h | 13 +++---
include/linux/sched.h | 2 +
kernel/dependency/dept.c | 66 ++++++++++++++++++++++++++-----
kernel/dependency/dept_internal.h | 5 +++
lib/Kconfig.debug | 10 +++++
7 files changed, 89 insertions(+), 21 deletions(-)
diff --git a/include/linux/dept.h b/include/linux/dept.h
index 2343d8c392d7..e70cbc6f41dc 100644
--- a/include/linux/dept.h
+++ b/include/linux/dept.h
@@ -139,8 +139,8 @@ extern void dept_free_range(void *start, unsigned int sz);
extern void dept_map_init(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
extern void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
extern void dept_map_copy(struct dept_map *to, struct dept_map *from);
-extern void dept_wait(struct dept_map *m, unsigned long w_f, unsigned long ip, const char *w_fn, int sub_l);
-extern void dept_stage_wait(struct dept_map *m, struct dept_key *k, unsigned long ip, const char *w_fn);
+extern void dept_wait(struct dept_map *m, unsigned long w_f, unsigned long ip, const char *w_fn, int sub_l, long timeout);
+extern void dept_stage_wait(struct dept_map *m, struct dept_key *k, unsigned long ip, const char *w_fn, long timeout);
extern void dept_request_event_wait_commit(void);
extern void dept_clean_stage(void);
extern void dept_ttwu_stage_wait(struct task_struct *t, unsigned long ip);
@@ -187,8 +187,8 @@ struct dept_map { };
#define dept_map_init(m, k, su, n) do { (void)(n); (void)(k); } while (0)
#define dept_map_reinit(m, k, su, n) do { (void)(n); (void)(k); } while (0)
#define dept_map_copy(t, f) do { } while (0)
-#define dept_wait(m, w_f, ip, w_fn, sl) do { (void)(w_fn); } while (0)
-#define dept_stage_wait(m, k, ip, w_fn) do { (void)(k); (void)(w_fn); } while (0)
+#define dept_wait(m, w_f, ip, w_fn, sl, t) do { (void)(w_fn); } while (0)
+#define dept_stage_wait(m, k, ip, w_fn, t) do { (void)(k); (void)(w_fn); } while (0)
#define dept_request_event_wait_commit() do { } while (0)
#define dept_clean_stage() do { } while (0)
#define dept_ttwu_stage_wait(t, ip) do { } while (0)
diff --git a/include/linux/dept_ldt.h b/include/linux/dept_ldt.h
index 8047d0a531f1..730af2517ecd 100644
--- a/include/linux/dept_ldt.h
+++ b/include/linux/dept_ldt.h
@@ -28,7 +28,7 @@
else if (t) \
dept_ecxt_enter(m, LDT_EVT_L, i, "trylock", "unlock", sl);\
else { \
- dept_wait(m, LDT_EVT_L, i, "lock", sl); \
+ dept_wait(m, LDT_EVT_L, i, "lock", sl, false); \
dept_ecxt_enter(m, LDT_EVT_L, i, "lock", "unlock", sl);\
} \
} while (0)
@@ -40,7 +40,7 @@
else if (t) \
dept_ecxt_enter(m, LDT_EVT_R, i, "read_trylock", "read_unlock", sl);\
else { \
- dept_wait(m, q ? LDT_EVT_RW : LDT_EVT_W, i, "read_lock", sl);\
+ dept_wait(m, q ? LDT_EVT_RW : LDT_EVT_W, i, "read_lock", sl, false);\
dept_ecxt_enter(m, LDT_EVT_R, i, "read_lock", "read_unlock", sl);\
} \
} while (0)
@@ -52,7 +52,7 @@
else if (t) \
dept_ecxt_enter(m, LDT_EVT_W, i, "write_trylock", "write_unlock", sl);\
else { \
- dept_wait(m, LDT_EVT_RW, i, "write_lock", sl); \
+ dept_wait(m, LDT_EVT_RW, i, "write_lock", sl, false);\
dept_ecxt_enter(m, LDT_EVT_W, i, "write_lock", "write_unlock", sl);\
} \
} while (0)
diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h
index 0535f763b21b..14917df0cc30 100644
--- a/include/linux/dept_sdt.h
+++ b/include/linux/dept_sdt.h
@@ -23,11 +23,12 @@
#define sdt_map_init_key(m, k) dept_map_init(m, k, 0, #m)
-#define sdt_wait(m) \
+#define sdt_wait_timeout(m, t) \
do { \
dept_request_event(m); \
- dept_wait(m, 1UL, _THIS_IP_, __func__, 0); \
+ dept_wait(m, 1UL, _THIS_IP_, __func__, 0, t); \
} while (0)
+#define sdt_wait(m) sdt_wait_timeout(m, -1L)
/*
* sdt_might_sleep() and its family will be committed in __schedule()
@@ -38,13 +39,13 @@
/*
* Use the code location as the class key if an explicit map is not used.
*/
-#define sdt_might_sleep_start(m) \
+#define sdt_might_sleep_start_timeout(m, t) \
do { \
struct dept_map *__m = m; \
static struct dept_key __key; \
- dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__);\
+ dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__, t);\
} while (0)
-
+#define sdt_might_sleep_start(m) sdt_might_sleep_start_timeout(m, -1L)
#define sdt_might_sleep_end() dept_clean_stage()
#define sdt_ecxt_enter(m) dept_ecxt_enter(m, 1UL, _THIS_IP_, "start", "event", 0)
@@ -54,7 +55,9 @@
#else /* !CONFIG_DEPT */
#define sdt_map_init(m) do { } while (0)
#define sdt_map_init_key(m, k) do { (void)(k); } while (0)
+#define sdt_wait_timeout(m, t) do { } while (0)
#define sdt_wait(m) do { } while (0)
+#define sdt_might_sleep_start_timeout(m, t) do { } while (0)
#define sdt_might_sleep_start(m) do { } while (0)
#define sdt_might_sleep_end() do { } while (0)
#define sdt_ecxt_enter(m) do { } while (0)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1cd0e78f3323..385c5b3c5b0b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -870,6 +870,7 @@ struct dept_task {
bool stage_sched_map;
const char *stage_w_fn;
unsigned long stage_ip;
+ bool stage_timeout;
arch_spinlock_t stage_lock;
/*
@@ -910,6 +911,7 @@ struct dept_task {
.stage_sched_map = false, \
.stage_w_fn = NULL, \
.stage_ip = 0UL, \
+ .stage_timeout = false, \
.stage_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED,\
.missing_ecxt = 0, \
.hardirqs_enabled = false, \
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index f4c08758f8db..519b2151403e 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -757,6 +757,8 @@ static void print_diagram(struct dept_dep *d)
if (!irqf) {
print_spc(spc, "[S] %s(%s:%d)\n", c_fn, fc_n, fc->sub_id);
print_spc(spc, "[W] %s(%s:%d)\n", w_fn, tc_n, tc->sub_id);
+ if (w->timeout)
+ print_spc(spc, "--------------- >8 timeout ---------------\n");
print_spc(spc, "[E] %s(%s:%d)\n", e_fn, fc_n, fc->sub_id);
}
}
@@ -810,6 +812,24 @@ static void print_dep(struct dept_dep *d)
static void save_current_stack(int skip);
+static bool is_timeout_wait_circle(struct dept_class *c)
+{
+ struct dept_class *fc = c->bfs_parent;
+ struct dept_class *tc = c;
+
+ do {
+ struct dept_dep *d = lookup_dep(fc, tc);
+
+ if (d->wait->timeout)
+ return true;
+
+ tc = fc;
+ fc = fc->bfs_parent;
+ } while (tc != c);
+
+ return false;
+}
+
/*
* Print all classes in a circle.
*/
@@ -832,10 +852,14 @@ static void print_circle(struct dept_class *c)
pr_warn("summary\n");
pr_warn("---------------------------------------------------\n");
- if (fc == tc)
+ if (is_timeout_wait_circle(c)) {
+ pr_warn("NOT A DEADLOCK BUT A CIRCULAR DEPENDENCY\n");
+ pr_warn("CHECK IF THE TIMEOUT IS INTENDED\n\n");
+ } else if (fc == tc) {
pr_warn("*** AA DEADLOCK ***\n\n");
- else
+ } else {
pr_warn("*** DEADLOCK ***\n\n");
+ }
i = 0;
do {
@@ -1579,7 +1603,8 @@ static int next_wgen(void)
}
static void add_wait(struct dept_class *c, unsigned long ip,
- const char *w_fn, int sub_l, bool sched_sleep)
+ const char *w_fn, int sub_l, bool sched_sleep,
+ bool timeout)
{
struct dept_task *dt = dept_task();
struct dept_wait *w;
@@ -1599,6 +1624,7 @@ static void add_wait(struct dept_class *c, unsigned long ip,
w->wait_fn = w_fn;
w->wait_stack = get_current_stack();
w->sched_sleep = sched_sleep;
+ w->timeout = timeout;
cxt = cur_cxt();
if (cxt == DEPT_CXT_HIRQ || cxt == DEPT_CXT_SIRQ)
@@ -2297,7 +2323,7 @@ static struct dept_class *check_new_class(struct dept_key *local,
*/
static void __dept_wait(struct dept_map *m, unsigned long w_f,
unsigned long ip, const char *w_fn, int sub_l,
- bool sched_sleep, bool sched_map)
+ bool sched_sleep, bool sched_map, bool timeout)
{
int e;
@@ -2320,7 +2346,7 @@ static void __dept_wait(struct dept_map *m, unsigned long w_f,
if (!c)
continue;
- add_wait(c, ip, w_fn, sub_l, sched_sleep);
+ add_wait(c, ip, w_fn, sub_l, sched_sleep, timeout);
}
}
@@ -2355,14 +2381,23 @@ static void __dept_event(struct dept_map *m, struct dept_map *real_m,
}
void dept_wait(struct dept_map *m, unsigned long w_f,
- unsigned long ip, const char *w_fn, int sub_l)
+ unsigned long ip, const char *w_fn, int sub_l,
+ long timeoutval)
{
struct dept_task *dt = dept_task();
unsigned long flags;
+ bool timeout;
if (unlikely(!dept_working()))
return;
+ timeout = timeoutval > 0 && timeoutval < MAX_SCHEDULE_TIMEOUT;
+
+#if !defined(CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT)
+ if (timeout)
+ return;
+#endif
+
if (dt->recursive)
return;
@@ -2371,21 +2406,30 @@ void dept_wait(struct dept_map *m, unsigned long w_f,
flags = dept_enter();
- __dept_wait(m, w_f, ip, w_fn, sub_l, false, false);
+ __dept_wait(m, w_f, ip, w_fn, sub_l, false, false, timeout);
dept_exit(flags);
}
EXPORT_SYMBOL_GPL(dept_wait);
void dept_stage_wait(struct dept_map *m, struct dept_key *k,
- unsigned long ip, const char *w_fn)
+ unsigned long ip, const char *w_fn,
+ long timeoutval)
{
struct dept_task *dt = dept_task();
unsigned long flags;
+ bool timeout;
if (unlikely(!dept_working()))
return;
+ timeout = timeoutval > 0 && timeoutval < MAX_SCHEDULE_TIMEOUT;
+
+#if !defined(CONFIG_DEPT_AGGRESSIVE_TIMEOUT_WAIT)
+ if (timeout)
+ return;
+#endif
+
if (m && m->nocheck)
return;
@@ -2434,6 +2478,7 @@ void dept_stage_wait(struct dept_map *m, struct dept_key *k,
dt->stage_w_fn = w_fn;
dt->stage_ip = ip;
+ dt->stage_timeout = timeout;
arch_spin_unlock(&dt->stage_lock);
exit:
dept_exit_recursive(flags);
@@ -2447,6 +2492,7 @@ static void __dept_clean_stage(struct dept_task *dt)
dt->stage_sched_map = false;
dt->stage_w_fn = NULL;
dt->stage_ip = 0UL;
+ dt->stage_timeout = false;
}
void dept_clean_stage(void)
@@ -2479,6 +2525,7 @@ void dept_request_event_wait_commit(void)
unsigned long ip;
const char *w_fn;
bool sched_map;
+ bool timeout;
if (unlikely(!dept_working()))
return;
@@ -2505,12 +2552,13 @@ void dept_request_event_wait_commit(void)
w_fn = dt->stage_w_fn;
ip = dt->stage_ip;
sched_map = dt->stage_sched_map;
+ timeout = dt->stage_timeout;
wg = next_wgen();
WRITE_ONCE(dt->stage_m.wgen, wg);
arch_spin_unlock(&dt->stage_lock);
- __dept_wait(&dt->stage_m, 1UL, ip, w_fn, 0, true, sched_map);
+ __dept_wait(&dt->stage_m, 1UL, ip, w_fn, 0, true, sched_map, timeout);
exit:
dept_exit(flags);
}
diff --git a/kernel/dependency/dept_internal.h b/kernel/dependency/dept_internal.h
index 4c4d7bacec15..aa1a588805b3 100644
--- a/kernel/dependency/dept_internal.h
+++ b/kernel/dependency/dept_internal.h
@@ -238,6 +238,11 @@ struct dept_wait {
* whether this wait is for commit in scheduler
*/
bool sched_sleep;
+
+ /*
+ * whether a timeout is set
+ */
+ bool timeout;
};
};
};
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 712514e2c149..540583425d8e 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1394,6 +1394,16 @@ config DEPT
noting, to mitigate the impact by the false positives, multi
reporting has been supported.
+config DEPT_AGGRESSIVE_TIMEOUT_WAIT
+ bool "Aggressively track even timeout waits"
+ depends on DEPT
+ default n
+ help
+ Timeout wait doesn't contribute to a deadlock. However,
+ informing a circular dependency might be helpful for cases
+ that timeout is used to avoid a deadlock. Say N if you'd like
+ to avoid verbose reports.
+
config LOCK_DEBUGGING_SUPPORT
bool
depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
--
2.17.1
^ permalink raw reply related
* [PATCH v18 13/42] dept: apply sdt_might_sleep_{start,end}() to hashed-waitqueue wait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Make dept able to track dependencies by hashed-waitqueue waits.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/wait_bit.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h
index 9e29d79fc790..179a616ad245 100644
--- a/include/linux/wait_bit.h
+++ b/include/linux/wait_bit.h
@@ -6,6 +6,7 @@
* Linux wait-bit related types and methods:
*/
#include <linux/wait.h>
+#include <linux/dept_sdt.h>
struct wait_bit_key {
unsigned long *flags;
@@ -257,6 +258,7 @@ extern wait_queue_head_t *__var_waitqueue(void *p);
struct wait_bit_queue_entry __wbq_entry; \
long __ret = ret; /* explicit shadow */ \
\
+ sdt_might_sleep_start(NULL); \
init_wait_var_entry(&__wbq_entry, var, \
exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
for (;;) { \
@@ -274,6 +276,7 @@ extern wait_queue_head_t *__var_waitqueue(void *p);
cmd; \
} \
finish_wait(__wq_head, &__wbq_entry.wq_entry); \
+ sdt_might_sleep_end(); \
__out: __ret; \
})
--
2.17.1
^ permalink raw reply related
* [PATCH v18 12/42] dept: apply sdt_might_sleep_{start,end}() to waitqueue wait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Make dept able to track dependencies by waitqueue waits.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/wait.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/wait.h b/include/linux/wait.h
index f648044466d5..7815caf61a15 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -7,6 +7,7 @@
#include <linux/list.h>
#include <linux/stddef.h>
#include <linux/spinlock.h>
+#include <linux/dept_sdt.h>
#include <asm/current.h>
@@ -305,6 +306,7 @@ extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
struct wait_queue_entry __wq_entry; \
long __ret = ret; /* explicit shadow */ \
\
+ sdt_might_sleep_start(NULL); \
init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
for (;;) { \
long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
@@ -323,6 +325,7 @@ extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
break; \
} \
finish_wait(&wq_head, &__wq_entry); \
+ sdt_might_sleep_end(); \
__out: __ret; \
})
--
2.17.1
^ permalink raw reply related
* [PATCH v18 11/42] dept: apply sdt_might_sleep_{start,end}() to swait
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Make dept able to track dependencies by swaits.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/swait.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/swait.h b/include/linux/swait.h
index d324419482a0..277ac74f61c3 100644
--- a/include/linux/swait.h
+++ b/include/linux/swait.h
@@ -6,6 +6,7 @@
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
+#include <linux/dept_sdt.h>
#include <asm/current.h>
/*
@@ -161,6 +162,7 @@ extern void finish_swait(struct swait_queue_head *q, struct swait_queue *wait);
struct swait_queue __wait; \
long __ret = ret; \
\
+ sdt_might_sleep_start(NULL); \
INIT_LIST_HEAD(&__wait.task_list); \
for (;;) { \
long __int = prepare_to_swait_event(&wq, &__wait, state);\
@@ -176,6 +178,7 @@ extern void finish_swait(struct swait_queue_head *q, struct swait_queue *wait);
cmd; \
} \
finish_swait(&wq, &__wait); \
+ sdt_might_sleep_end(); \
__out: __ret; \
})
--
2.17.1
^ permalink raw reply related
* [PATCH v18 10/42] dept: apply sdt_might_sleep_{start,end}() to wait_for_completion()/complete()
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Make dept able to track dependencies by wait_for_completion()/complete().
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/completion.h | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/include/linux/completion.h b/include/linux/completion.h
index fb2915676574..bd2c207481d6 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -10,6 +10,7 @@
*/
#include <linux/swait.h>
+#include <linux/dept_sdt.h>
/*
* struct completion - structure used to maintain state for a "completion"
@@ -26,14 +27,33 @@
struct completion {
unsigned int done;
struct swait_queue_head wait;
+ struct dept_map dmap;
};
+#define init_completion(x) \
+do { \
+ sdt_map_init(&(x)->dmap); \
+ __init_completion(x); \
+} while (0)
+
+/*
+ * XXX: No use cases for now. Fill the body when needed.
+ */
#define init_completion_map(x, m) init_completion(x)
-static inline void complete_acquire(struct completion *x) {}
-static inline void complete_release(struct completion *x) {}
+
+static inline void complete_acquire(struct completion *x)
+{
+ sdt_might_sleep_start(&x->dmap);
+}
+
+static inline void complete_release(struct completion *x)
+{
+ sdt_might_sleep_end();
+}
#define COMPLETION_INITIALIZER(work) \
- { 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
+ { 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait), \
+ .dmap = DEPT_MAP_INITIALIZER(work, NULL), }
#define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
(*({ init_completion_map(&(work), &(map)); &(work); }))
@@ -75,13 +95,13 @@ static inline void complete_release(struct completion *x) {}
#endif
/**
- * init_completion - Initialize a dynamically allocated completion
+ * __init_completion - Initialize a dynamically allocated completion
* @x: pointer to completion structure that is to be initialized
*
* This inline function will initialize a dynamically created completion
* structure.
*/
-static inline void init_completion(struct completion *x)
+static inline void __init_completion(struct completion *x)
{
x->done = 0;
init_swait_queue_head(&x->wait);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 08/42] dept: add a mechanism to refill the internal memory pools on running out
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
dept engine works in a constrained environment. For example, dept
cannot make use of dynamic allocation e.g. kmalloc(). So dept has been
using static pools to keep memory chunks dept uses.
However, dept would barely work once any of the pools gets run out. So
implemented a mechanism for the refill on the lack, using irq work and
workqueue that fits on the contrained environment.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
kernel/dependency/dept.c | 108 +++++++++++++++++++++++++-----
kernel/dependency/dept_internal.h | 19 ++++--
kernel/dependency/dept_object.h | 10 +--
kernel/dependency/dept_proc.c | 8 +--
4 files changed, 116 insertions(+), 29 deletions(-)
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index 953e1b81a81f..1b16a6095b3c 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -75,6 +75,9 @@
#include <linux/dept.h>
#include <linux/utsname.h>
#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/irq_work.h>
+#include <linux/vmalloc.h>
#include "dept_internal.h"
static int dept_stop;
@@ -143,9 +146,11 @@ static inline struct dept_task *dept_task(void)
} \
})
-#define DEPT_INFO_ONCE(s...) pr_warn_once("DEPT_INFO_ONCE: " s)
+#define DEPT_INFO_ONCE(s...) pr_warn_once("DEPT_INFO_ONCE: " s)
+#define DEPT_INFO(s...) pr_warn("DEPT_INFO: " s)
static arch_spinlock_t dept_spin = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+static arch_spinlock_t dept_pool_spin = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
/*
* DEPT internal engine should be cautious in using outside functions
@@ -268,6 +273,7 @@ static bool valid_key(struct dept_key *k)
#define OBJECT(id, nr) \
static struct dept_##id spool_##id[nr]; \
+static struct dept_##id rpool_##id[nr]; \
static DEFINE_PER_CPU(struct llist_head, lpool_##id);
#include "dept_object.h"
#undef OBJECT
@@ -276,14 +282,74 @@ struct dept_pool dept_pool[OBJECT_NR] = {
#define OBJECT(id, nr) { \
.name = #id, \
.obj_sz = sizeof(struct dept_##id), \
- .obj_nr = ATOMIC_INIT(nr), \
+ .obj_nr = nr, \
+ .tot_nr = nr, \
+ .acc_sz = ATOMIC_INIT(sizeof(spool_##id) + sizeof(rpool_##id)), \
.node_off = offsetof(struct dept_##id, pool_node), \
.spool = spool_##id, \
+ .rpool = rpool_##id, \
.lpool = &lpool_##id, },
#include "dept_object.h"
#undef OBJECT
};
+static void dept_wq_work_fn(struct work_struct *work)
+{
+ int i;
+
+ for (i = 0; i < OBJECT_NR; i++) {
+ struct dept_pool *p = dept_pool + i;
+ int sz = p->tot_nr * p->obj_sz;
+ void *rpool;
+ bool need;
+
+ local_irq_disable();
+ arch_spin_lock(&dept_pool_spin);
+ need = !p->rpool;
+ arch_spin_unlock(&dept_pool_spin);
+ local_irq_enable();
+
+ if (!need)
+ continue;
+
+ rpool = vmalloc(sz);
+
+ if (!rpool) {
+ DEPT_STOP("Failed to extend internal resources.\n");
+ break;
+ }
+
+ local_irq_disable();
+ arch_spin_lock(&dept_pool_spin);
+ if (!p->rpool) {
+ p->rpool = rpool;
+ rpool = NULL;
+ atomic_add(sz, &p->acc_sz);
+ }
+ arch_spin_unlock(&dept_pool_spin);
+ local_irq_enable();
+
+ if (rpool)
+ vfree(rpool);
+ else
+ DEPT_INFO("Dept object(%s) just got refilled successfully.\n", p->name);
+ }
+}
+
+static DECLARE_WORK(dept_wq_work, dept_wq_work_fn);
+
+static void dept_irq_work_fn(struct irq_work *w)
+{
+ schedule_work(&dept_wq_work);
+}
+
+static DEFINE_IRQ_WORK(dept_irq_work, dept_irq_work_fn);
+
+static void request_rpool_refill(void)
+{
+ irq_work_queue(&dept_irq_work);
+}
+
/*
* Can use llist no matter whether CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG is
* enabled or not because NMI and other contexts in the same CPU never
@@ -319,19 +385,31 @@ static void *from_pool(enum object_t t)
/*
* Try static pool.
*/
- if (atomic_read(&p->obj_nr) > 0) {
- int idx = atomic_dec_return(&p->obj_nr);
+ arch_spin_lock(&dept_pool_spin);
+
+ if (!p->obj_nr) {
+ p->spool = p->rpool;
+ p->obj_nr = p->rpool ? p->tot_nr : 0;
+ p->rpool = NULL;
+ request_rpool_refill();
+ }
+
+ if (p->obj_nr) {
+ void *ret;
+
+ p->obj_nr--;
+ ret = p->spool + (p->obj_nr * p->obj_sz);
+ arch_spin_unlock(&dept_pool_spin);
- if (idx >= 0)
- return p->spool + (idx * p->obj_sz);
+ return ret;
}
+ arch_spin_unlock(&dept_pool_spin);
- DEPT_INFO_ONCE("---------------------------------------------\n"
- " Some of Dept internal resources are run out.\n"
- " Dept might still work if the resources get freed.\n"
- " However, the chances are Dept will suffer from\n"
- " the lack from now. Needs to extend the internal\n"
- " resource pools. Ask max.byungchul.park@gmail.com\n");
+ DEPT_INFO("------------------------------------------\n"
+ " Dept object(%s) is run out.\n"
+ " Dept is trying to refill the object.\n"
+ " Nevertheless, if it fails, Dept will stop.\n",
+ p->name);
return NULL;
}
@@ -2957,8 +3035,8 @@ void __init dept_init(void)
pr_info("... DEPT_MAX_ECXT_HELD : %d\n", DEPT_MAX_ECXT_HELD);
pr_info("... DEPT_MAX_SUBCLASSES : %d\n", DEPT_MAX_SUBCLASSES);
#define OBJECT(id, nr) \
- pr_info("... memory used by %s: %zu KB\n", \
- #id, B2KB(sizeof(struct dept_##id) * nr));
+ pr_info("... memory initially used by %s: %zu KB\n", \
+ #id, B2KB(sizeof(spool_##id) + sizeof(rpool_##id)));
#include "dept_object.h"
#undef OBJECT
#define HASH(id, bits) \
@@ -2966,6 +3044,6 @@ void __init dept_init(void)
#id, B2KB(sizeof(struct hlist_head) * (1 << (bits))));
#include "dept_hash.h"
#undef HASH
- pr_info("... total memory used by objects and hashs: %zu KB\n", B2KB(mem_total));
+ pr_info("... total memory initially used by objects and hashs: %zu KB\n", B2KB(mem_total));
pr_info("... per task memory footprint: %zu bytes\n", sizeof(struct dept_task));
}
diff --git a/kernel/dependency/dept_internal.h b/kernel/dependency/dept_internal.h
index 262114a0110c..4c4d7bacec15 100644
--- a/kernel/dependency/dept_internal.h
+++ b/kernel/dependency/dept_internal.h
@@ -26,9 +26,19 @@ struct dept_pool {
size_t obj_sz;
/*
- * the number of the static array
+ * the remaining number of the object in spool
*/
- atomic_t obj_nr;
+ int obj_nr;
+
+ /*
+ * the number of the object in spool
+ */
+ int tot_nr;
+
+ /*
+ * accumulated amount of memory used by the object in byte
+ */
+ atomic_t acc_sz;
/*
* offset of ->pool_node
@@ -38,9 +48,10 @@ struct dept_pool {
/*
* pointer to the pool
*/
- void *spool;
+ void *spool; /* static pool */
+ void *rpool; /* reserved pool */
struct llist_head boot_pool;
- struct llist_head __percpu *lpool;
+ struct llist_head __percpu *lpool; /* local pool */
};
struct dept_ecxt;
diff --git a/kernel/dependency/dept_object.h b/kernel/dependency/dept_object.h
index 0b7eb16fe9fb..4f936adfa8ee 100644
--- a/kernel/dependency/dept_object.h
+++ b/kernel/dependency/dept_object.h
@@ -6,8 +6,8 @@
* nr: # of the object that should be kept in the pool.
*/
-OBJECT(dep, 1024 * 8)
-OBJECT(class, 1024 * 8)
-OBJECT(stack, 1024 * 32)
-OBJECT(ecxt, 1024 * 16)
-OBJECT(wait, 1024 * 32)
+OBJECT(dep, 1024 * 4 * 2)
+OBJECT(class, 1024 * 4)
+OBJECT(stack, 1024 * 4 * 8)
+OBJECT(ecxt, 1024 * 4 * 2)
+OBJECT(wait, 1024 * 4 * 4)
diff --git a/kernel/dependency/dept_proc.c b/kernel/dependency/dept_proc.c
index 97beaf397715..f28992834588 100644
--- a/kernel/dependency/dept_proc.c
+++ b/kernel/dependency/dept_proc.c
@@ -74,12 +74,10 @@ static int dept_stats_show(struct seq_file *m, void *v)
{
int r;
- seq_puts(m, "Availability in the static pools:\n\n");
+ seq_puts(m, "Accumulated amount of memory used by pools:\n\n");
#define OBJECT(id, nr) \
- r = atomic_read(&dept_pool[OBJECT_##id].obj_nr); \
- if (r < 0) \
- r = 0; \
- seq_printf(m, "%s\t%d/%d(%d%%)\n", #id, r, nr, (r * 100) / (nr));
+ r = atomic_read(&dept_pool[OBJECT_##id].acc_sz); \
+ seq_printf(m, "%s\t%d KB\n", #id, r / 1024);
#include "dept_object.h"
#undef OBJECT
--
2.17.1
^ permalink raw reply related
* [PATCH v18 09/42] dept: record the latest one out of consecutive waits of the same class
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
The current code records all the waits for later use to track relation
between waits and events within each context. However, since the same
class is handled the same way, it'd be okay to record only one on behalf
of the others if they all have the same class.
Even though it's the ideal to search the whole history buffer for that,
since it'd cost too high, alternatively, let's keep the latest one when
the same class'ed waits consecutively appear.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
kernel/dependency/dept.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index 1b16a6095b3c..f4c08758f8db 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -1486,9 +1486,28 @@ static struct dept_wait_hist *new_hist(void)
return wh;
}
+static struct dept_wait_hist *last_hist(void)
+{
+ int pos_n = hist_pos_next();
+ struct dept_wait_hist *wh_n = hist(pos_n);
+
+ /*
+ * This is the first try.
+ */
+ if (!pos_n && !wh_n->wait)
+ return NULL;
+
+ return hist(pos_n + DEPT_MAX_WAIT_HIST - 1);
+}
+
static void add_hist(struct dept_wait *w, unsigned int wg, unsigned int ctxt_id)
{
- struct dept_wait_hist *wh = new_hist();
+ struct dept_wait_hist *wh;
+
+ wh = last_hist();
+
+ if (!wh || wh->wait->class != w->class || wh->ctxt_id != ctxt_id)
+ wh = new_hist();
if (likely(wh->wait))
put_wait(wh->wait);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 07/42] dept: distinguish each work from another
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Workqueue already provides concurrency control. By that, any wait in a
work doesn't prevents events in other works with the control enabled.
Thus, each work would better be considered a different context.
So let dept assign a different context id to each work.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
kernel/workqueue.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 253311af47c6..ab7425adc826 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -55,6 +55,7 @@
#include <linux/kvm_para.h>
#include <linux/delay.h>
#include <linux/irq_work.h>
+#include <linux/dept.h>
#include "workqueue_internal.h"
@@ -3174,6 +3175,8 @@ __acquires(&pool->lock)
lockdep_copy_map(&lockdep_map, &work->lockdep_map);
#endif
+ dept_update_cxt();
+
/* ensure we're on the correct CPU */
WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
raw_smp_processor_id() != pool->cpu);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 06/42] dept: distinguish each kernel context from another
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Each unique kernel context, in dept's point of view, should be
identified on every entrance to kernel mode e.g. system call or user
oriented fault. Otherwise, dept may track meaningless dependencies
across different kernel context.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/dept.h | 17 +++++---
include/linux/irq-entry-common.h | 4 ++
include/linux/sched.h | 10 ++---
kernel/dependency/dept.c | 67 ++++++++++++++++---------------
kernel/dependency/dept_internal.h | 12 +++---
5 files changed, 61 insertions(+), 49 deletions(-)
diff --git a/include/linux/dept.h b/include/linux/dept.h
index a6d14b585a8d..2343d8c392d7 100644
--- a/include/linux/dept.h
+++ b/include/linux/dept.h
@@ -24,11 +24,16 @@ struct task_struct;
#define DEPT_MAX_SUBCLASSES_USR (DEPT_MAX_SUBCLASSES / DEPT_MAX_SUBCLASSES_EVT)
#define DEPT_MAX_SUBCLASSES_CACHE 2
-#define DEPT_SIRQ 0
-#define DEPT_HIRQ 1
-#define DEPT_IRQS_NR 2
-#define DEPT_SIRQF (1UL << DEPT_SIRQ)
-#define DEPT_HIRQF (1UL << DEPT_HIRQ)
+enum {
+ DEPT_CXT_SIRQ = 0,
+ DEPT_CXT_HIRQ,
+ DEPT_CXT_IRQS_NR,
+ DEPT_CXT_PROCESS = DEPT_CXT_IRQS_NR,
+ DEPT_CXTS_NR
+};
+
+#define DEPT_SIRQF (1UL << DEPT_CXT_SIRQ)
+#define DEPT_HIRQF (1UL << DEPT_CXT_HIRQ)
struct dept_key {
union {
@@ -146,6 +151,7 @@ extern void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip,
extern void dept_ecxt_exit(struct dept_map *m, unsigned long e_f, unsigned long ip);
extern void dept_sched_enter(void);
extern void dept_sched_exit(void);
+extern void dept_update_cxt(void);
static inline void dept_ecxt_enter_nokeep(struct dept_map *m)
{
@@ -193,6 +199,7 @@ struct dept_map { };
#define dept_ecxt_exit(m, e_f, ip) do { } while (0)
#define dept_sched_enter() do { } while (0)
#define dept_sched_exit() do { } while (0)
+#define dept_update_cxt() do { } while (0)
#define dept_ecxt_enter_nokeep(m) do { } while (0)
#define dept_key_init(k) do { (void)(k); } while (0)
#define dept_key_destroy(k) do { (void)(k); } while (0)
diff --git a/include/linux/irq-entry-common.h b/include/linux/irq-entry-common.h
index 6ab913e57da0..126bac5806a3 100644
--- a/include/linux/irq-entry-common.h
+++ b/include/linux/irq-entry-common.h
@@ -9,6 +9,7 @@
#include <linux/syscalls.h>
#include <linux/tick.h>
#include <linux/unwind_deferred.h>
+#include <linux/dept.h>
#include <asm/entry-common.h>
@@ -88,6 +89,9 @@ static __always_inline bool arch_in_rcu_eqs(void) { return false; }
*/
static __always_inline void enter_from_user_mode(struct pt_regs *regs)
{
+ /* Make dept work with a new context. */
+ dept_update_cxt();
+
arch_enter_from_user_mode(regs);
lockdep_hardirqs_off(CALLER_ADDR0);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 33e713c3ba70..1cd0e78f3323 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -833,19 +833,19 @@ struct dept_task {
int wait_hist_pos;
/*
- * sequential id to identify each IRQ context
+ * sequential id to identify each context
*/
- unsigned int irq_id[DEPT_IRQS_NR];
+ unsigned int cxt_id[DEPT_CXTS_NR];
/*
* for tracking IRQ-enabled points with cross-event
*/
- unsigned int wgen_enirq[DEPT_IRQS_NR];
+ unsigned int wgen_enirq[DEPT_CXT_IRQS_NR];
/*
* for keeping up-to-date IRQ-enabled points
*/
- unsigned long enirq_ip[DEPT_IRQS_NR];
+ unsigned long enirq_ip[DEPT_CXT_IRQS_NR];
/*
* for reserving a current stack instance at each operation
@@ -899,7 +899,7 @@ struct dept_task {
.wait_hist = { { .wait = NULL, } }, \
.ecxt_held_pos = 0, \
.wait_hist_pos = 0, \
- .irq_id = { 0U }, \
+ .cxt_id = { 0U }, \
.wgen_enirq = { 0U }, \
.enirq_ip = { 0UL }, \
.stack = NULL, \
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index dfe9dfdb6991..953e1b81a81f 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -230,9 +230,9 @@ static struct dept_class *dep_tc(struct dept_dep *d)
static const char *irq_str(int irq)
{
- if (irq == DEPT_SIRQ)
+ if (irq == DEPT_CXT_SIRQ)
return "softirq";
- if (irq == DEPT_HIRQ)
+ if (irq == DEPT_CXT_HIRQ)
return "hardirq";
return "(unknown)";
}
@@ -410,7 +410,7 @@ static void initialize_class(struct dept_class *c)
{
int i;
- for (i = 0; i < DEPT_IRQS_NR; i++) {
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++) {
struct dept_iecxt *ie = &c->iecxt[i];
struct dept_iwait *iw = &c->iwait[i];
@@ -436,7 +436,7 @@ static void initialize_ecxt(struct dept_ecxt *e)
{
int i;
- for (i = 0; i < DEPT_IRQS_NR; i++) {
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++) {
e->enirq_stack[i] = NULL;
e->enirq_ip[i] = 0UL;
}
@@ -452,7 +452,7 @@ static void initialize_wait(struct dept_wait *w)
{
int i;
- for (i = 0; i < DEPT_IRQS_NR; i++) {
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++) {
w->irq_stack[i] = NULL;
w->irq_ip[i] = 0UL;
}
@@ -491,7 +491,7 @@ static void destroy_ecxt(struct dept_ecxt *e)
{
int i;
- for (i = 0; i < DEPT_IRQS_NR; i++)
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++)
if (e->enirq_stack[i])
put_stack(e->enirq_stack[i]);
if (e->class)
@@ -507,7 +507,7 @@ static void destroy_wait(struct dept_wait *w)
{
int i;
- for (i = 0; i < DEPT_IRQS_NR; i++)
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++)
if (w->irq_stack[i])
put_stack(w->irq_stack[i]);
if (w->class)
@@ -665,7 +665,7 @@ static void print_diagram(struct dept_dep *d)
const char *tc_n = tc->sched_map ? "<sched>" : (tc->name ?: "(unknown)");
irqf = e->enirqf & w->irqf;
- for_each_set_bit(irq, &irqf, DEPT_IRQS_NR) {
+ for_each_set_bit(irq, &irqf, DEPT_CXT_IRQS_NR) {
if (!firstline)
pr_warn("\nor\n\n");
firstline = false;
@@ -698,7 +698,7 @@ static void print_dep(struct dept_dep *d)
const char *tc_n = tc->sched_map ? "<sched>" : (tc->name ?: "(unknown)");
irqf = e->enirqf & w->irqf;
- for_each_set_bit(irq, &irqf, DEPT_IRQS_NR) {
+ for_each_set_bit(irq, &irqf, DEPT_CXT_IRQS_NR) {
pr_warn("%s has been enabled:\n", irq_str(irq));
print_ip_stack(e->enirq_ip[irq], e->enirq_stack[irq]);
pr_warn("\n");
@@ -866,7 +866,7 @@ static void bfs(void *root, struct bfs_ops *ops, void *in, void **out)
*/
static unsigned long cur_enirqf(void);
-static int cur_irq(void);
+static int cur_cxt(void);
static unsigned int cur_ctxt_id(void);
static struct dept_iecxt *iecxt(struct dept_class *c, int irq)
@@ -1443,7 +1443,7 @@ static void add_dep(struct dept_ecxt *e, struct dept_wait *w)
if (d) {
check_dl_bfs(d);
- for (i = 0; i < DEPT_IRQS_NR; i++) {
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++) {
struct dept_iwait *fiw = iwait(fc, i);
struct dept_iecxt *found_ie;
struct dept_iwait *found_iw;
@@ -1487,7 +1487,7 @@ static void add_wait(struct dept_class *c, unsigned long ip,
struct dept_task *dt = dept_task();
struct dept_wait *w;
unsigned int wg;
- int irq;
+ int cxt;
int i;
if (DEPT_WARN_ON(!valid_class(c)))
@@ -1503,9 +1503,9 @@ static void add_wait(struct dept_class *c, unsigned long ip,
w->wait_stack = get_current_stack();
w->sched_sleep = sched_sleep;
- irq = cur_irq();
- if (irq < DEPT_IRQS_NR)
- add_iwait(c, irq, w);
+ cxt = cur_cxt();
+ if (cxt == DEPT_CXT_HIRQ || cxt == DEPT_CXT_SIRQ)
+ add_iwait(c, cxt, w);
/*
* Avoid adding dependency between user aware nested ecxt and
@@ -1579,7 +1579,7 @@ static struct dept_ecxt_held *add_ecxt(struct dept_map *m,
eh->sub_l = sub_l;
irqf = cur_enirqf();
- for_each_set_bit(irq, &irqf, DEPT_IRQS_NR)
+ for_each_set_bit(irq, &irqf, DEPT_CXT_IRQS_NR)
add_iecxt(c, irq, e, false);
del_ecxt(e);
@@ -1728,7 +1728,7 @@ static void do_event(struct dept_map *m, struct dept_map *real_m,
add_dep(eh->ecxt, wh->wait);
}
- for (i = 0; i < DEPT_IRQS_NR; i++) {
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++) {
struct dept_ecxt *e;
if (before(dt->wgen_enirq[i], wg))
@@ -1775,7 +1775,7 @@ static void disconnect_class(struct dept_class *c)
call_rcu(&d->rh, del_dep_rcu);
}
- for (i = 0; i < DEPT_IRQS_NR; i++) {
+ for (i = 0; i < DEPT_CXT_IRQS_NR; i++) {
stale_iecxt(iecxt(c, i));
stale_iwait(iwait(c, i));
}
@@ -1800,27 +1800,21 @@ static unsigned long cur_enirqf(void)
return 0UL;
}
-static int cur_irq(void)
+static int cur_cxt(void)
{
if (lockdep_softirq_context(current))
- return DEPT_SIRQ;
+ return DEPT_CXT_SIRQ;
if (lockdep_hardirq_context())
- return DEPT_HIRQ;
- return DEPT_IRQS_NR;
+ return DEPT_CXT_HIRQ;
+ return DEPT_CXT_PROCESS;
}
static unsigned int cur_ctxt_id(void)
{
struct dept_task *dt = dept_task();
- int irq = cur_irq();
+ int cxt = cur_cxt();
- /*
- * Normal process context
- */
- if (irq == DEPT_IRQS_NR)
- return 0U;
-
- return dt->irq_id[irq] | (1UL << irq);
+ return dt->cxt_id[cxt] | (1UL << cxt);
}
static void enirq_transition(int irq)
@@ -1877,7 +1871,7 @@ static void dept_enirq(unsigned long ip)
flags = dept_enter();
- for_each_set_bit(irq, &irqf, DEPT_IRQS_NR) {
+ for_each_set_bit(irq, &irqf, DEPT_CXT_IRQS_NR) {
dt->enirq_ip[irq] = ip;
enirq_transition(irq);
}
@@ -1923,6 +1917,13 @@ void noinstr dept_hardirqs_off(void)
dept_task()->hardirqs_enabled = false;
}
+void noinstr dept_update_cxt(void)
+{
+ struct dept_task *dt = dept_task();
+
+ dt->cxt_id[DEPT_CXT_PROCESS] += 1UL << DEPT_CXTS_NR;
+}
+
/*
* Ensure it's the outmost softirq context.
*/
@@ -1930,7 +1931,7 @@ void dept_softirq_enter(void)
{
struct dept_task *dt = dept_task();
- dt->irq_id[DEPT_SIRQ] += 1UL << DEPT_IRQS_NR;
+ dt->cxt_id[DEPT_CXT_SIRQ] += 1UL << DEPT_CXTS_NR;
}
/*
@@ -1940,7 +1941,7 @@ void noinstr dept_hardirq_enter(void)
{
struct dept_task *dt = dept_task();
- dt->irq_id[DEPT_HIRQ] += 1UL << DEPT_IRQS_NR;
+ dt->cxt_id[DEPT_CXT_HIRQ] += 1UL << DEPT_CXTS_NR;
}
void dept_sched_enter(void)
diff --git a/kernel/dependency/dept_internal.h b/kernel/dependency/dept_internal.h
index a1eb1ed647a7..262114a0110c 100644
--- a/kernel/dependency/dept_internal.h
+++ b/kernel/dependency/dept_internal.h
@@ -106,8 +106,8 @@ struct dept_class {
/*
* for tracking IRQ dependencies
*/
- struct dept_iecxt iecxt[DEPT_IRQS_NR];
- struct dept_iwait iwait[DEPT_IRQS_NR];
+ struct dept_iecxt iecxt[DEPT_CXT_IRQS_NR];
+ struct dept_iwait iwait[DEPT_CXT_IRQS_NR];
/*
* classified by a map embedded in task_struct,
@@ -169,8 +169,8 @@ struct dept_ecxt {
/*
* where the IRQ-enabled happened
*/
- unsigned long enirq_ip[DEPT_IRQS_NR];
- struct dept_stack *enirq_stack[DEPT_IRQS_NR];
+ unsigned long enirq_ip[DEPT_CXT_IRQS_NR];
+ struct dept_stack *enirq_stack[DEPT_CXT_IRQS_NR];
/*
* where the event context started
@@ -214,8 +214,8 @@ struct dept_wait {
/*
* where the IRQ wait happened
*/
- unsigned long irq_ip[DEPT_IRQS_NR];
- struct dept_stack *irq_stack[DEPT_IRQS_NR];
+ unsigned long irq_ip[DEPT_CXT_IRQS_NR];
+ struct dept_stack *irq_stack[DEPT_CXT_IRQS_NR];
/*
* where the wait happened
--
2.17.1
^ permalink raw reply related
* [PATCH v18 05/42] dept: add proc knobs to show stats and dependency graph
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
It'd be useful to show dept internal stats and dependency graph on
runtime via proc for better information. Introduce the knobs.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
kernel/dependency/Makefile | 1 +
kernel/dependency/dept.c | 11 +---
kernel/dependency/dept_internal.h | 10 ++++
kernel/dependency/dept_proc.c | 96 +++++++++++++++++++++++++++++++
4 files changed, 109 insertions(+), 9 deletions(-)
create mode 100644 kernel/dependency/dept_proc.c
diff --git a/kernel/dependency/Makefile b/kernel/dependency/Makefile
index b5cfb8a03c0c..92f165400187 100644
--- a/kernel/dependency/Makefile
+++ b/kernel/dependency/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_DEPT) += dept.o
+obj-$(CONFIG_DEPT) += dept_proc.o
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index 18b238931699..dfe9dfdb6991 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -266,20 +266,13 @@ static bool valid_key(struct dept_key *k)
* have been freed will be placed.
*/
-enum object_t {
-#define OBJECT(id, nr) OBJECT_##id,
- #include "dept_object.h"
-#undef OBJECT
- OBJECT_NR,
-};
-
#define OBJECT(id, nr) \
static struct dept_##id spool_##id[nr]; \
static DEFINE_PER_CPU(struct llist_head, lpool_##id);
#include "dept_object.h"
#undef OBJECT
-static struct dept_pool dept_pool[OBJECT_NR] = {
+struct dept_pool dept_pool[OBJECT_NR] = {
#define OBJECT(id, nr) { \
.name = #id, \
.obj_sz = sizeof(struct dept_##id), \
@@ -2083,7 +2076,7 @@ void dept_map_copy(struct dept_map *to, struct dept_map *from)
clean_classes_cache(&to->map_key);
}
-static LIST_HEAD(dept_classes);
+LIST_HEAD(dept_classes);
static bool within(const void *addr, void *start, unsigned long size)
{
diff --git a/kernel/dependency/dept_internal.h b/kernel/dependency/dept_internal.h
index 9b28398fecfd..a1eb1ed647a7 100644
--- a/kernel/dependency/dept_internal.h
+++ b/kernel/dependency/dept_internal.h
@@ -279,5 +279,15 @@ struct dept_hash {
int bits;
};
+enum object_t {
+#define OBJECT(id, nr) OBJECT_##id,
+ #include "dept_object.h"
+#undef OBJECT
+ OBJECT_NR,
+};
+
+extern struct list_head dept_classes;
+extern struct dept_pool dept_pool[];
+
#endif
#endif /* __DEPT_INTERNAL_H */
diff --git a/kernel/dependency/dept_proc.c b/kernel/dependency/dept_proc.c
new file mode 100644
index 000000000000..97beaf397715
--- /dev/null
+++ b/kernel/dependency/dept_proc.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Procfs knobs for Dept(DEPendency Tracker)
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ * Copyright (C) 2021 LG Electronics, Inc. , Byungchul Park
+ * Copyright (C) 2024 SK hynix, Inc. , Byungchul Park
+ */
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/dept.h>
+#include "dept_internal.h"
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ /*
+ * XXX: Serialize list traversal if needed. The following might
+ * give a wrong information on contention.
+ */
+ return seq_list_next(v, &dept_classes, pos);
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+ /*
+ * XXX: Serialize list traversal if needed. The following might
+ * give a wrong information on contention.
+ */
+ return seq_list_start_head(&dept_classes, *pos);
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+ struct dept_class *fc = list_entry(v, struct dept_class, all_node);
+ struct dept_dep *d;
+ const char *prefix;
+
+ if (v == &dept_classes) {
+ seq_puts(m, "All classes:\n\n");
+ return 0;
+ }
+
+ prefix = fc->sched_map ? "<sched> " : "";
+ seq_printf(m, "[%p] %s%s\n", (void *)fc->key, prefix, fc->name);
+
+ /*
+ * XXX: Serialize list traversal if needed. The following might
+ * give a wrong information on contention.
+ */
+ list_for_each_entry(d, &fc->dep_head, dep_node) {
+ struct dept_class *tc = d->wait->class;
+
+ prefix = tc->sched_map ? "<sched> " : "";
+ seq_printf(m, " -> [%p] %s%s\n", (void *)tc->key, prefix, tc->name);
+ }
+ seq_puts(m, "\n");
+
+ return 0;
+}
+
+static const struct seq_operations dept_deps_ops = {
+ .start = l_start,
+ .next = l_next,
+ .stop = l_stop,
+ .show = l_show,
+};
+
+static int dept_stats_show(struct seq_file *m, void *v)
+{
+ int r;
+
+ seq_puts(m, "Availability in the static pools:\n\n");
+#define OBJECT(id, nr) \
+ r = atomic_read(&dept_pool[OBJECT_##id].obj_nr); \
+ if (r < 0) \
+ r = 0; \
+ seq_printf(m, "%s\t%d/%d(%d%%)\n", #id, r, nr, (r * 100) / (nr));
+ #include "dept_object.h"
+#undef OBJECT
+
+ return 0;
+}
+
+static int __init dept_proc_init(void)
+{
+ proc_create_seq("dept_deps", S_IRUSR, NULL, &dept_deps_ops);
+ proc_create_single("dept_stats", S_IRUSR, NULL, dept_stats_show);
+ return 0;
+}
+
+__initcall(dept_proc_init);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 04/42] dept: tie to lockdep and IRQ tracing
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
How to place dept this way looks so ugly. However, it's inevitable for
now. The way should be enhanced gradually.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/irqflags.h | 7 +-
include/linux/local_lock_internal.h | 1 +
include/linux/lockdep.h | 102 ++++++++++++++++++++++------
include/linux/lockdep_types.h | 3 +
include/linux/mutex.h | 1 +
include/linux/percpu-rwsem.h | 2 +-
include/linux/rtmutex.h | 1 +
include/linux/rwlock_types.h | 1 +
include/linux/rwsem.h | 1 +
include/linux/seqlock.h | 2 +-
include/linux/spinlock_types_raw.h | 3 +
include/linux/srcu.h | 2 +-
kernel/dependency/dept.c | 8 +--
kernel/locking/lockdep.c | 22 ++++++
14 files changed, 127 insertions(+), 29 deletions(-)
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 57b074e0cfbb..d8b9cf093f83 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -15,6 +15,7 @@
#include <linux/irqflags_types.h>
#include <linux/typecheck.h>
#include <linux/cleanup.h>
+#include <linux/dept.h>
#include <asm/irqflags.h>
#include <asm/percpu.h>
@@ -55,8 +56,10 @@ extern void trace_hardirqs_off(void);
# define lockdep_softirqs_enabled(p) ((p)->softirqs_enabled)
# define lockdep_hardirq_enter() \
do { \
- if (__this_cpu_inc_return(hardirq_context) == 1)\
+ if (__this_cpu_inc_return(hardirq_context) == 1) { \
current->hardirq_threaded = 0; \
+ dept_hardirq_enter(); \
+ } \
} while (0)
# define lockdep_hardirq_threaded() \
do { \
@@ -131,6 +134,8 @@ do { \
# define lockdep_softirq_enter() \
do { \
current->softirq_context++; \
+ if (current->softirq_context == 1) \
+ dept_softirq_enter(); \
} while (0)
# define lockdep_softirq_exit() \
do { \
diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index 8f82b4eb542f..3e30fea95f92 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -30,6 +30,7 @@ typedef struct {
.name = #lockname, \
.wait_type_inner = LD_WAIT_CONFIG, \
.lock_type = LD_LOCK_PERCPU, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL),\
}, \
.owner = NULL,
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index dd634103b014..ebfc781c3095 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -12,6 +12,7 @@
#include <linux/lockdep_types.h>
#include <linux/smp.h>
+#include <linux/dept_ldt.h>
#include <asm/percpu.h>
struct task_struct;
@@ -39,6 +40,8 @@ static inline void lockdep_copy_map(struct lockdep_map *to,
*/
for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
to->class_cache[i] = NULL;
+
+ dept_map_copy(&to->dmap, &from->dmap);
}
/*
@@ -428,7 +431,8 @@ enum xhlock_context_t {
* Note that _name must not be NULL.
*/
#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
- { .name = (_name), .key = (void *)(_key), }
+ { .name = (_name), .key = (void *)(_key), \
+ .dmap = DEPT_MAP_INITIALIZER(_name, _key) }
static inline void lockdep_invariant_state(bool force) {}
static inline void lockdep_free_task(struct task_struct *task) {}
@@ -510,33 +514,89 @@ extern bool read_lock_is_recursive(void);
#define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
#define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
-#define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
-#define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
-#define spin_release(l, i) lock_release(l, i)
-
-#define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
+#define spin_acquire(l, s, t, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, NULL, i); \
+ lock_acquire_exclusive(l, s, t, NULL, i); \
+} while (0)
+#define spin_acquire_nest(l, s, t, n, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, n, i); \
+ lock_acquire_exclusive(l, s, t, n, i); \
+} while (0)
+#define spin_release(l, i) \
+do { \
+ ldt_unlock(&(l)->dmap, i); \
+ lock_release(l, i); \
+} while (0)
+#define rwlock_acquire(l, s, t, i) \
+do { \
+ ldt_wlock(&(l)->dmap, s, t, NULL, i); \
+ lock_acquire_exclusive(l, s, t, NULL, i); \
+} while (0)
#define rwlock_acquire_read(l, s, t, i) \
do { \
+ ldt_rlock(&(l)->dmap, s, t, NULL, i, !read_lock_is_recursive());\
if (read_lock_is_recursive()) \
lock_acquire_shared_recursive(l, s, t, NULL, i); \
else \
lock_acquire_shared(l, s, t, NULL, i); \
} while (0)
-
-#define rwlock_release(l, i) lock_release(l, i)
-
-#define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
-#define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
-#define seqcount_release(l, i) lock_release(l, i)
-
-#define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
-#define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
-#define mutex_release(l, i) lock_release(l, i)
-
-#define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
-#define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
-#define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
-#define rwsem_release(l, i) lock_release(l, i)
+#define rwlock_release(l, i) \
+do { \
+ ldt_unlock(&(l)->dmap, i); \
+ lock_release(l, i); \
+} while (0)
+#define seqcount_acquire(l, s, t, i) \
+do { \
+ ldt_wlock(&(l)->dmap, s, t, NULL, i); \
+ lock_acquire_exclusive(l, s, t, NULL, i); \
+} while (0)
+#define seqcount_acquire_read(l, s, t, i) \
+do { \
+ ldt_rlock(&(l)->dmap, s, t, NULL, i, false); \
+ lock_acquire_shared_recursive(l, s, t, NULL, i); \
+} while (0)
+#define seqcount_release(l, i) \
+do { \
+ ldt_unlock(&(l)->dmap, i); \
+ lock_release(l, i); \
+} while (0)
+#define mutex_acquire(l, s, t, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, NULL, i); \
+ lock_acquire_exclusive(l, s, t, NULL, i); \
+} while (0)
+#define mutex_acquire_nest(l, s, t, n, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, n, i); \
+ lock_acquire_exclusive(l, s, t, n, i); \
+} while (0)
+#define mutex_release(l, i) \
+do { \
+ ldt_unlock(&(l)->dmap, i); \
+ lock_release(l, i); \
+} while (0)
+#define rwsem_acquire(l, s, t, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, NULL, i); \
+ lock_acquire_exclusive(l, s, t, NULL, i); \
+} while (0)
+#define rwsem_acquire_nest(l, s, t, n, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, n, i); \
+ lock_acquire_exclusive(l, s, t, n, i); \
+} while (0)
+#define rwsem_acquire_read(l, s, t, i) \
+do { \
+ ldt_lock(&(l)->dmap, s, t, NULL, i); \
+ lock_acquire_shared(l, s, t, NULL, i); \
+} while (0)
+#define rwsem_release(l, i) \
+do { \
+ ldt_unlock(&(l)->dmap, i); \
+ lock_release(l, i); \
+} while (0)
#define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
#define lock_map_acquire_try(l) lock_acquire_exclusive(l, 0, 1, NULL, _THIS_IP_)
diff --git a/include/linux/lockdep_types.h b/include/linux/lockdep_types.h
index eae115a26488..0c3389ed26b6 100644
--- a/include/linux/lockdep_types.h
+++ b/include/linux/lockdep_types.h
@@ -11,6 +11,7 @@
#define __LINUX_LOCKDEP_TYPES_H
#include <linux/types.h>
+#include <linux/dept.h>
#define MAX_LOCKDEP_SUBCLASSES 8UL
@@ -77,6 +78,7 @@ struct lock_class_key {
struct hlist_node hash_entry;
struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
};
+ struct dept_key dkey;
};
extern struct lock_class_key __lockdep_no_validate__;
@@ -195,6 +197,7 @@ struct lockdep_map {
int cpu;
unsigned long ip;
#endif
+ struct dept_map dmap;
};
struct pin_cookie { unsigned int val; };
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index bf535f0118bb..dae4f3fede49 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -29,6 +29,7 @@ struct device;
, .dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_SLEEP, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL),\
}
#else
# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 288f5235649a..11eece738f1f 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -22,7 +22,7 @@ struct percpu_rw_semaphore {
};
#ifdef CONFIG_DEBUG_LOCK_ALLOC
-#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname },
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname, .dmap = DEPT_MAP_INITIALIZER(lockname, NULL) },
#else
#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)
#endif
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index ede4c6bf6f22..ac68c3e5e2ec 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -91,6 +91,7 @@ do { \
.dep_map = { \
.name = #mutexname, \
.wait_type_inner = LD_WAIT_SLEEP, \
+ .dmap = DEPT_MAP_INITIALIZER(mutexname, NULL),\
}
#else
#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h
index 1948442e7750..6e58dfc84997 100644
--- a/include/linux/rwlock_types.h
+++ b/include/linux/rwlock_types.h
@@ -10,6 +10,7 @@
.dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_CONFIG, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL), \
}
#else
# define RW_DEP_MAP_INIT(lockname)
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index f1aaf676a874..0f349c83a7dc 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -22,6 +22,7 @@
.dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_SLEEP, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL),\
},
#else
# define __RWSEM_DEP_MAP_INIT(lockname)
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index a8a8661839b6..5f18e11be14e 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -51,7 +51,7 @@ static inline void __seqcount_init(seqcount_t *s, const char *name,
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define SEQCOUNT_DEP_MAP_INIT(lockname) \
- .dep_map = { .name = #lockname }
+ .dep_map = { .name = #lockname, .dmap = DEPT_MAP_INITIALIZER(lockname, NULL) }
/**
* seqcount_init() - runtime initializer for seqcount_t
diff --git a/include/linux/spinlock_types_raw.h b/include/linux/spinlock_types_raw.h
index 91cb36b65a17..3dcc551ded25 100644
--- a/include/linux/spinlock_types_raw.h
+++ b/include/linux/spinlock_types_raw.h
@@ -31,11 +31,13 @@ typedef struct raw_spinlock {
.dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_SPIN, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL),\
}
# define SPIN_DEP_MAP_INIT(lockname) \
.dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_CONFIG, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL),\
}
# define LOCAL_SPIN_DEP_MAP_INIT(lockname) \
@@ -43,6 +45,7 @@ typedef struct raw_spinlock {
.name = #lockname, \
.wait_type_inner = LD_WAIT_CONFIG, \
.lock_type = LD_LOCK_PERCPU, \
+ .dmap = DEPT_MAP_INITIALIZER(lockname, NULL),\
}
#else
# define RAW_SPIN_DEP_MAP_INIT(lockname)
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 344ad51c8f6c..61c0ca3a1ef8 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -53,7 +53,7 @@ int __init_srcu_struct_fast_updown(struct srcu_struct *ssp, const char *name,
__init_srcu_struct_fast_updown((ssp), #ssp, &__srcu_key); \
})
-#define __SRCU_DEP_MAP_INIT(srcu_name) .dep_map = { .name = #srcu_name },
+#define __SRCU_DEP_MAP_INIT(srcu_name) .dep_map = { .name = #srcu_name, .dmap = DEPT_MAP_INITIALIZER(srcu_name, NULL) },
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
int init_srcu_struct(struct srcu_struct *ssp);
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index f2a9456f63f6..18b238931699 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -250,10 +250,10 @@ static bool dept_working(void)
* Even k == NULL is considered as a valid key because it would use
* &->map_key as the key in that case.
*/
-struct dept_key __dept_no_validate__;
+extern struct lock_class_key __lockdep_no_validate__;
static bool valid_key(struct dept_key *k)
{
- return &__dept_no_validate__ != k;
+ return &__lockdep_no_validate__.dkey != k;
}
/*
@@ -1921,7 +1921,7 @@ void dept_softirqs_off(void)
dept_task()->softirqs_enabled = false;
}
-void dept_hardirqs_off(void)
+void noinstr dept_hardirqs_off(void)
{
/*
* Assumes that it's called with IRQ disabled so that accessing
@@ -1943,7 +1943,7 @@ void dept_softirq_enter(void)
/*
* Ensure it's the outmost hardirq context.
*/
-void dept_hardirq_enter(void)
+void noinstr dept_hardirq_enter(void)
{
struct dept_task *dt = dept_task();
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2d4c5bab5af8..dc97f2753ef8 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1224,6 +1224,8 @@ void lockdep_register_key(struct lock_class_key *key)
struct lock_class_key *k;
unsigned long flags;
+ dept_key_init(&key->dkey);
+
if (WARN_ON_ONCE(static_obj(key)))
return;
hash_head = keyhashentry(key);
@@ -4361,6 +4363,8 @@ static void __trace_hardirqs_on_caller(void)
*/
void lockdep_hardirqs_on_prepare(void)
{
+ dept_hardirqs_on();
+
if (unlikely(!debug_locks))
return;
@@ -4481,6 +4485,8 @@ EXPORT_SYMBOL_GPL(lockdep_hardirqs_on);
*/
void noinstr lockdep_hardirqs_off(unsigned long ip)
{
+ dept_hardirqs_off();
+
if (unlikely(!debug_locks))
return;
@@ -4525,6 +4531,8 @@ void lockdep_softirqs_on(unsigned long ip)
{
struct irqtrace_events *trace = ¤t->irqtrace;
+ dept_softirqs_on_ip(ip);
+
if (unlikely(!lockdep_enabled()))
return;
@@ -4563,6 +4571,8 @@ void lockdep_softirqs_on(unsigned long ip)
*/
void lockdep_softirqs_off(unsigned long ip)
{
+ dept_softirqs_off();
+
if (unlikely(!lockdep_enabled()))
return;
@@ -4940,6 +4950,8 @@ void lockdep_init_map_type(struct lockdep_map *lock, const char *name,
{
int i;
+ ldt_init(&lock->dmap, &key->dkey, subclass, name);
+
for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
lock->class_cache[i] = NULL;
@@ -5736,6 +5748,12 @@ void lock_set_class(struct lockdep_map *lock, const char *name,
{
unsigned long flags;
+ /*
+ * dept_map_(re)init() might be called twice redundantly. But
+ * there's no choice as long as Dept relies on Lockdep.
+ */
+ ldt_set_class(&lock->dmap, name, &key->dkey, subclass, ip);
+
if (unlikely(!lockdep_enabled()))
return;
@@ -5753,6 +5771,8 @@ void lock_downgrade(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
+ ldt_downgrade(&lock->dmap, ip);
+
if (unlikely(!lockdep_enabled()))
return;
@@ -6588,6 +6608,8 @@ void lockdep_unregister_key(struct lock_class_key *key)
bool found = false;
bool need_callback = false;
+ dept_key_destroy(&key->dkey);
+
might_sleep();
if (WARN_ON_ONCE(static_obj(key)))
--
2.17.1
^ permalink raw reply related
* [PATCH v18 03/42] dept: add lock dependency tracker APIs
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Wrap the base APIs for easier annotation on typical lock.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/dept_ldt.h | 78 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 78 insertions(+)
create mode 100644 include/linux/dept_ldt.h
diff --git a/include/linux/dept_ldt.h b/include/linux/dept_ldt.h
new file mode 100644
index 000000000000..8047d0a531f1
--- /dev/null
+++ b/include/linux/dept_ldt.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Lock Dependency Tracker
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ * Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ * Copyright (c) 2024 SK hynix, Inc., Byungchul Park
+ */
+
+#ifndef __LINUX_DEPT_LDT_H
+#define __LINUX_DEPT_LDT_H
+
+#include <linux/dept.h>
+
+#ifdef CONFIG_DEPT
+#define LDT_EVT_L 1UL
+#define LDT_EVT_R 2UL
+#define LDT_EVT_W 1UL
+#define LDT_EVT_RW (LDT_EVT_R | LDT_EVT_W)
+#define LDT_EVT_ALL (LDT_EVT_L | LDT_EVT_RW)
+
+#define ldt_init(m, k, su, n) dept_map_init(m, k, su, n)
+#define ldt_lock(m, sl, t, n, i) \
+ do { \
+ if (n) \
+ dept_ecxt_enter_nokeep(m); \
+ else if (t) \
+ dept_ecxt_enter(m, LDT_EVT_L, i, "trylock", "unlock", sl);\
+ else { \
+ dept_wait(m, LDT_EVT_L, i, "lock", sl); \
+ dept_ecxt_enter(m, LDT_EVT_L, i, "lock", "unlock", sl);\
+ } \
+ } while (0)
+
+#define ldt_rlock(m, sl, t, n, i, q) \
+ do { \
+ if (n) \
+ dept_ecxt_enter_nokeep(m); \
+ else if (t) \
+ dept_ecxt_enter(m, LDT_EVT_R, i, "read_trylock", "read_unlock", sl);\
+ else { \
+ dept_wait(m, q ? LDT_EVT_RW : LDT_EVT_W, i, "read_lock", sl);\
+ dept_ecxt_enter(m, LDT_EVT_R, i, "read_lock", "read_unlock", sl);\
+ } \
+ } while (0)
+
+#define ldt_wlock(m, sl, t, n, i) \
+ do { \
+ if (n) \
+ dept_ecxt_enter_nokeep(m); \
+ else if (t) \
+ dept_ecxt_enter(m, LDT_EVT_W, i, "write_trylock", "write_unlock", sl);\
+ else { \
+ dept_wait(m, LDT_EVT_RW, i, "write_lock", sl); \
+ dept_ecxt_enter(m, LDT_EVT_W, i, "write_lock", "write_unlock", sl);\
+ } \
+ } while (0)
+
+#define ldt_unlock(m, i) dept_ecxt_exit(m, LDT_EVT_ALL, i)
+
+#define ldt_downgrade(m, i) \
+ do { \
+ if (dept_ecxt_holding(m, LDT_EVT_W)) \
+ dept_map_ecxt_modify(m, LDT_EVT_W, NULL, LDT_EVT_R, i, "downgrade", "read_unlock", -1);\
+ } while (0)
+
+#define ldt_set_class(m, n, k, sl, i) dept_map_ecxt_modify(m, LDT_EVT_ALL, k, 0UL, i, "lock_set_class", "(any)unlock", sl)
+#else /* !CONFIG_DEPT */
+#define ldt_init(m, k, su, n) do { (void)(k); } while (0)
+#define ldt_lock(m, sl, t, n, i) do { } while (0)
+#define ldt_rlock(m, sl, t, n, i, q) do { } while (0)
+#define ldt_wlock(m, sl, t, n, i) do { } while (0)
+#define ldt_unlock(m, i) do { } while (0)
+#define ldt_downgrade(m, i) do { } while (0)
+#define ldt_set_class(m, n, k, sl, i) do { } while (0)
+#endif
+#endif /* __LINUX_DEPT_LDT_H */
--
2.17.1
^ permalink raw reply related
* [PATCH v18 01/42] dept: implement DEPT(DEPendency Tracker)
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
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Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
CURRENT STATUS
--------------
Lockdep tracks lock acquisition order to identify deadlock conditions.
Additionally, it tracks IRQ state changes — via {en,dis}able — to detect
cases where locks are acquired unintentionally during interrupt handling.
PROBLEM
-------
Waits and their associated events that are never reachable can
eventually lead to deadlocks. However, since Lockdep focuses solely on
lock acquisition order, it has inherent limitations when handling waits
and events.
Moreover, by tracking only lock acquisition order, Lockdep cannot
properly handle read locks or cross-event scenarios — such as
wait_for_completion() and complete() — making it increasingly inadequate
as a general-purpose deadlock detection tool.
SOLUTION
--------
Once again, waits and their associated events that are never reachable
can eventually lead to deadlocks. The new solution, DEPT, focuses
directly on waits and events. DEPT monitors waits and events, and
reports them when any become unreachable.
DEPT provides:
* Correct handling of read locks.
* Support for general waits and events.
* Continuous operation, even after multiple reports.
* Simple, intuitive annotation APIs.
Q & A
-----
Q. Is this the first attempt to solve this problem?
A. No. The cross-release feature (commit b09be676e0ff2) attempted to
address it — as a Lockdep extension. It was merged, but quickly
reverted, because:
While it uncovered valuable hidden issues, it also introduced false
positives. Since these false positives mask further real problems
with Lockdep — and developers strongly dislike them — the feature was
rolled back.
Q. Why wasn’t DEPT built as a Lockdep extension?
A. Lockdep is the result of years of work by kernel developers — and is
now very stable. But I chose to build DEPT separately, because:
While reusing BFS(Breadth First Search) and Lockdep’s hashing is
beneficial, the rest of the system must be rebuilt from scratch to
align with DEPT’s wait-event model — since Lockdep was originally
designed for tracking lock acquisition orders, not wait-event
dependencies.
Q. Do you plan to replace Lockdep entirely?
A. Not at all — Lockdep still plays a vital role in validating correct
lock usage. While its dependency-checking logic should eventually be
superseded by DEPT, the rest of its functionality should stay.
Q. Should we replace the dependency check immediately?
A. Absolutely not. Lockdep’s stability is the result of years of hard
work by kernel developers. Lockdep and DEPT should run side by side
until DEPT matures.
Q. Stronger detection often leads to more false positives — which was a
major pain point when cross-release was added. Is DEPT designed to
handle this?
A. Yes. DEPT’s simple, generalized design enables flexible reporting —
so while false positives still need fixing, they’re far less
disruptive than they were under the Lockdep extension, cross-release.
Q. Why not fix all false positives out-of-tree before merging?
A. Since the affected subsystems span the entire kernel, like Lockdep,
which has relied on annotations to avoid false positives over the
last two decades, dept too will require the annotation efforts.
Performing annotation work within the mainline will help us add
annotations more appropriately and will also make dept a useful tool
for a wider range of users more quickly.
CONFIG_DEPT is marked EXPERIMENTAL, so it’s opt-in. Some users are
already interested in using DEPT to analyze complex synchronization
patterns and extract dependency insights.
Signed-off-by: Byungchul Park <byungchul@sk.com>
Tested-by: Harry Yoo <harry.yoo@oracle.com>
Tested-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Tested-by: Yunseong Kim <ysk@kzalloc.com>
Tested-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
include/linux/dept.h | 208 ++
include/linux/hardirq.h | 3 +
include/linux/sched.h | 108 ++
init/init_task.c | 2 +
init/main.c | 2 +
kernel/Makefile | 1 +
kernel/dependency/Makefile | 3 +
kernel/dependency/dept.c | 2977 +++++++++++++++++++++++++++++
kernel/dependency/dept_hash.h | 10 +
kernel/dependency/dept_internal.h | 283 +++
kernel/dependency/dept_object.h | 13 +
kernel/exit.c | 1 +
kernel/fork.c | 2 +
kernel/module/main.c | 4 +
kernel/sched/core.c | 9 +
lib/Kconfig.debug | 26 +
lib/locking-selftest.c | 2 +
17 files changed, 3654 insertions(+)
create mode 100644 include/linux/dept.h
create mode 100644 kernel/dependency/Makefile
create mode 100644 kernel/dependency/dept.c
create mode 100644 kernel/dependency/dept_hash.h
create mode 100644 kernel/dependency/dept_internal.h
create mode 100644 kernel/dependency/dept_object.h
diff --git a/include/linux/dept.h b/include/linux/dept.h
new file mode 100644
index 000000000000..a6d14b585a8d
--- /dev/null
+++ b/include/linux/dept.h
@@ -0,0 +1,208 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DEPT(DEPendency Tracker) - runtime dependency tracker
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ * Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ * Copyright (c) 2024 SK hynix, Inc., Byungchul Park
+ */
+
+#ifndef __LINUX_DEPT_H
+#define __LINUX_DEPT_H
+
+#ifdef CONFIG_DEPT
+
+struct task_struct;
+
+#define DEPT_MAX_STACK_ENTRY 16
+#define DEPT_MAX_WAIT_HIST 64
+#define DEPT_MAX_ECXT_HELD 48
+
+#define DEPT_MAX_SUBCLASSES 16
+#define DEPT_MAX_SUBCLASSES_EVT 2
+#define DEPT_MAX_SUBCLASSES_USR (DEPT_MAX_SUBCLASSES / DEPT_MAX_SUBCLASSES_EVT)
+#define DEPT_MAX_SUBCLASSES_CACHE 2
+
+#define DEPT_SIRQ 0
+#define DEPT_HIRQ 1
+#define DEPT_IRQS_NR 2
+#define DEPT_SIRQF (1UL << DEPT_SIRQ)
+#define DEPT_HIRQF (1UL << DEPT_HIRQ)
+
+struct dept_key {
+ union {
+ /*
+ * Each byte-wise address will be used as its key.
+ */
+ char base[DEPT_MAX_SUBCLASSES];
+
+ /*
+ * for caching the main class pointer
+ */
+ struct dept_class *classes[DEPT_MAX_SUBCLASSES_CACHE];
+ };
+};
+
+struct dept_map {
+ const char *name;
+ struct dept_key *keys;
+
+ /*
+ * subclass that can be set from user
+ */
+ int sub_u;
+
+ /*
+ * It's local copy for fast access to the associated classes.
+ * Also used for dept_key for static maps.
+ */
+ struct dept_key map_key;
+
+ /*
+ * wait timestamp associated to this map
+ */
+ unsigned int wgen;
+
+ /*
+ * whether this map should be going to be checked or not
+ */
+ bool nocheck;
+};
+
+#define DEPT_MAP_INITIALIZER(n, k) \
+{ \
+ .name = #n, \
+ .keys = (struct dept_key *)(k), \
+ .sub_u = 0, \
+ .map_key = { .classes = { NULL, } }, \
+ .wgen = 0U, \
+ .nocheck = false, \
+}
+
+struct dept_ecxt_held {
+ /*
+ * associated event context
+ */
+ struct dept_ecxt *ecxt;
+
+ /*
+ * unique key for this dept_ecxt_held
+ */
+ struct dept_map *map;
+
+ /*
+ * class of the ecxt of this dept_ecxt_held
+ */
+ struct dept_class *class;
+
+ /*
+ * the wgen when the event context started
+ */
+ unsigned int wgen;
+
+ /*
+ * subclass that only works in the local context
+ */
+ int sub_l;
+};
+
+struct dept_wait_hist {
+ /*
+ * associated wait
+ */
+ struct dept_wait *wait;
+
+ /*
+ * unique id of all waits system-wise until wrapped
+ */
+ unsigned int wgen;
+
+ /*
+ * local context id to identify IRQ context
+ */
+ unsigned int ctxt_id;
+};
+
+extern void dept_on(void);
+extern void dept_off(void);
+extern void dept_init(void);
+extern void dept_task_init(struct task_struct *t);
+extern void dept_task_exit(struct task_struct *t);
+extern void dept_free_range(void *start, unsigned int sz);
+
+extern void dept_map_init(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
+extern void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
+extern void dept_map_copy(struct dept_map *to, struct dept_map *from);
+extern void dept_wait(struct dept_map *m, unsigned long w_f, unsigned long ip, const char *w_fn, int sub_l);
+extern void dept_stage_wait(struct dept_map *m, struct dept_key *k, unsigned long ip, const char *w_fn);
+extern void dept_request_event_wait_commit(void);
+extern void dept_clean_stage(void);
+extern void dept_ttwu_stage_wait(struct task_struct *t, unsigned long ip);
+extern void dept_ecxt_enter(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *c_fn, const char *e_fn, int sub_l);
+extern bool dept_ecxt_holding(struct dept_map *m, unsigned long e_f);
+extern void dept_request_event(struct dept_map *m);
+extern void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *e_fn);
+extern void dept_ecxt_exit(struct dept_map *m, unsigned long e_f, unsigned long ip);
+extern void dept_sched_enter(void);
+extern void dept_sched_exit(void);
+
+static inline void dept_ecxt_enter_nokeep(struct dept_map *m)
+{
+ dept_ecxt_enter(m, 0UL, 0UL, NULL, NULL, 0);
+}
+
+/*
+ * for users who want to manage external keys
+ */
+extern void dept_key_init(struct dept_key *k);
+extern void dept_key_destroy(struct dept_key *k);
+extern void dept_map_ecxt_modify(struct dept_map *m, unsigned long e_f, struct dept_key *new_k, unsigned long new_e_f, unsigned long new_ip, const char *new_c_fn, const char *new_e_fn, int new_sub_l);
+
+extern void dept_softirq_enter(void);
+extern void dept_hardirq_enter(void);
+extern void dept_softirqs_on_ip(unsigned long ip);
+extern void dept_hardirqs_on(void);
+extern void dept_softirqs_off(void);
+extern void dept_hardirqs_off(void);
+#else /* !CONFIG_DEPT */
+struct dept_key { };
+struct dept_map { };
+
+#define DEPT_MAP_INITIALIZER(n, k) { }
+
+#define dept_on() do { } while (0)
+#define dept_off() do { } while (0)
+#define dept_init() do { } while (0)
+#define dept_task_init(t) do { } while (0)
+#define dept_task_exit(t) do { } while (0)
+#define dept_free_range(s, sz) do { } while (0)
+
+#define dept_map_init(m, k, su, n) do { (void)(n); (void)(k); } while (0)
+#define dept_map_reinit(m, k, su, n) do { (void)(n); (void)(k); } while (0)
+#define dept_map_copy(t, f) do { } while (0)
+#define dept_wait(m, w_f, ip, w_fn, sl) do { (void)(w_fn); } while (0)
+#define dept_stage_wait(m, k, ip, w_fn) do { (void)(k); (void)(w_fn); } while (0)
+#define dept_request_event_wait_commit() do { } while (0)
+#define dept_clean_stage() do { } while (0)
+#define dept_ttwu_stage_wait(t, ip) do { } while (0)
+#define dept_ecxt_enter(m, e_f, ip, c_fn, e_fn, sl) do { (void)(c_fn); (void)(e_fn); } while (0)
+#define dept_ecxt_holding(m, e_f) false
+#define dept_request_event(m) do { } while (0)
+#define dept_event(m, e_f, ip, e_fn) do { (void)(e_fn); } while (0)
+#define dept_ecxt_exit(m, e_f, ip) do { } while (0)
+#define dept_sched_enter() do { } while (0)
+#define dept_sched_exit() do { } while (0)
+#define dept_ecxt_enter_nokeep(m) do { } while (0)
+#define dept_key_init(k) do { (void)(k); } while (0)
+#define dept_key_destroy(k) do { (void)(k); } while (0)
+#define dept_map_ecxt_modify(m, e_f, n_k, n_e_f, n_ip, n_c_fn, n_e_fn, n_sl) do { (void)(n_k); (void)(n_c_fn); (void)(n_e_fn); } while (0)
+
+#define dept_softirq_enter() do { } while (0)
+#define dept_hardirq_enter() do { } while (0)
+#define dept_softirqs_on_ip(ip) do { } while (0)
+#define dept_hardirqs_on() do { } while (0)
+#define dept_softirqs_off() do { } while (0)
+#define dept_hardirqs_off() do { } while (0)
+#endif
+#endif /* __LINUX_DEPT_H */
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index d57cab4d4c06..bb279dbbe748 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -5,6 +5,7 @@
#include <linux/context_tracking_state.h>
#include <linux/preempt.h>
#include <linux/lockdep.h>
+#include <linux/dept.h>
#include <linux/ftrace_irq.h>
#include <linux/sched.h>
#include <linux/vtime.h>
@@ -106,6 +107,7 @@ void irq_exit_rcu(void);
*/
#define __nmi_enter() \
do { \
+ dept_off(); \
lockdep_off(); \
arch_nmi_enter(); \
BUG_ON(in_nmi() == NMI_MASK); \
@@ -128,6 +130,7 @@ void irq_exit_rcu(void);
__preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \
arch_nmi_exit(); \
lockdep_on(); \
+ dept_on(); \
} while (0)
#define nmi_exit() \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d395f2810fac..33e713c3ba70 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -49,6 +49,8 @@
#include <linux/tracepoint-defs.h>
#include <linux/unwind_deferred_types.h>
#include <asm/kmap_size.h>
+#include <linux/spinlock.h>
+#include <linux/dept.h>
#ifndef COMPILE_OFFSETS
#include <generated/rq-offsets.h>
#endif
@@ -816,6 +818,110 @@ struct kmap_ctrl {
#endif
};
+#ifdef CONFIG_DEPT
+struct dept_task {
+ /*
+ * all event contexts that have entered and before exiting
+ */
+ struct dept_ecxt_held ecxt_held[DEPT_MAX_ECXT_HELD];
+ int ecxt_held_pos;
+
+ /*
+ * ring buffer holding all waits that have happened
+ */
+ struct dept_wait_hist wait_hist[DEPT_MAX_WAIT_HIST];
+ int wait_hist_pos;
+
+ /*
+ * sequential id to identify each IRQ context
+ */
+ unsigned int irq_id[DEPT_IRQS_NR];
+
+ /*
+ * for tracking IRQ-enabled points with cross-event
+ */
+ unsigned int wgen_enirq[DEPT_IRQS_NR];
+
+ /*
+ * for keeping up-to-date IRQ-enabled points
+ */
+ unsigned long enirq_ip[DEPT_IRQS_NR];
+
+ /*
+ * for reserving a current stack instance at each operation
+ */
+ struct dept_stack *stack;
+
+ /*
+ * for preventing recursive call into DEPT engine
+ */
+ int recursive;
+
+ /*
+ * for preventing reentrance to WARN*() while warning
+ */
+ int in_warning;
+
+ /*
+ * for staging data to commit a wait
+ */
+ struct dept_map stage_m;
+ struct dept_map *stage_real_m;
+ bool stage_sched_map;
+ const char *stage_w_fn;
+ unsigned long stage_ip;
+ arch_spinlock_t stage_lock;
+
+ /*
+ * the number of missing ecxts
+ */
+ int missing_ecxt;
+
+ /*
+ * for tracking IRQ-enable state
+ */
+ bool hardirqs_enabled;
+ bool softirqs_enabled;
+
+ /*
+ * whether the current is on do_exit()
+ */
+ bool task_exit;
+
+ /*
+ * whether the current is running __schedule()
+ */
+ bool in_sched;
+};
+
+#define DEPT_TASK_INITIALIZER(t) \
+{ \
+ .wait_hist = { { .wait = NULL, } }, \
+ .ecxt_held_pos = 0, \
+ .wait_hist_pos = 0, \
+ .irq_id = { 0U }, \
+ .wgen_enirq = { 0U }, \
+ .enirq_ip = { 0UL }, \
+ .stack = NULL, \
+ .recursive = 0, \
+ .in_warning = 0, \
+ .stage_m = DEPT_MAP_INITIALIZER((t)->stage_m, NULL), \
+ .stage_real_m = NULL, \
+ .stage_sched_map = false, \
+ .stage_w_fn = NULL, \
+ .stage_ip = 0UL, \
+ .stage_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED,\
+ .missing_ecxt = 0, \
+ .hardirqs_enabled = false, \
+ .softirqs_enabled = false, \
+ .task_exit = false, \
+ .in_sched = false, \
+}
+#else
+struct dept_task { };
+#define DEPT_TASK_INITIALIZER(t) { }
+#endif
+
struct task_struct {
#ifdef CONFIG_THREAD_INFO_IN_TASK
/*
@@ -1274,6 +1380,8 @@ struct task_struct {
struct held_lock held_locks[MAX_LOCK_DEPTH];
#endif
+ struct dept_task dept_task;
+
#if defined(CONFIG_UBSAN) && !defined(CONFIG_UBSAN_TRAP)
unsigned int in_ubsan;
#endif
diff --git a/init/init_task.c b/init/init_task.c
index 49b13d7c3985..8ce30b835fc3 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -14,6 +14,7 @@
#include <linux/numa.h>
#include <linux/scs.h>
#include <linux/plist.h>
+#include <linux/dept.h>
#include <linux/uaccess.h>
@@ -234,6 +235,7 @@ struct task_struct init_task __aligned(L1_CACHE_BYTES) = {
.curr_chain_key = INITIAL_CHAIN_KEY,
.lockdep_recursion = 0,
#endif
+ .dept_task = DEPT_TASK_INITIALIZER(init_task),
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.ret_stack = NULL,
.tracing_graph_pause = ATOMIC_INIT(0),
diff --git a/init/main.c b/init/main.c
index 07a3116811c5..a3d7db9e3d7a 100644
--- a/init/main.c
+++ b/init/main.c
@@ -66,6 +66,7 @@
#include <linux/debug_locks.h>
#include <linux/debugobjects.h>
#include <linux/lockdep.h>
+#include <linux/dept.h>
#include <linux/kmemleak.h>
#include <linux/padata.h>
#include <linux/pid_namespace.h>
@@ -1051,6 +1052,7 @@ void start_kernel(void)
panic_param);
lockdep_init();
+ dept_init();
/*
* Need to run this when irqs are enabled, because it wants
diff --git a/kernel/Makefile b/kernel/Makefile
index 9fe722305c9b..859dab7af192 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -56,6 +56,7 @@ obj-y += dma/
obj-y += entry/
obj-y += unwind/
obj-$(CONFIG_MODULES) += module/
+obj-y += dependency/
obj-$(CONFIG_KCMP) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
diff --git a/kernel/dependency/Makefile b/kernel/dependency/Makefile
new file mode 100644
index 000000000000..b5cfb8a03c0c
--- /dev/null
+++ b/kernel/dependency/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_DEPT) += dept.o
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
new file mode 100644
index 000000000000..f2a9456f63f6
--- /dev/null
+++ b/kernel/dependency/dept.c
@@ -0,0 +1,2977 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DEPT(DEPendency Tracker) - Runtime dependency tracker
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ * Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ * Copyright (c) 2024 SK hynix, Inc., Byungchul Park
+ *
+ * DEPT provides a general way to detect potential deadlocks at runtime
+ * and the interest is not limited to typical lock but to every
+ * synchronization primitives.
+ *
+ * The following ideas were borrowed from LOCKDEP:
+ *
+ * 1) Use a graph to track relationship between classes.
+ * 2) Prevent performance regression using hash.
+ *
+ * The following items were enhanced from LOCKDEP:
+ *
+ * 1) Cover more deadlock cases.
+ * 2) Allow multiple reports.
+ *
+ * TODO: Both LOCKDEP and DEPT should co-exist until DEPT is considered
+ * stable. Then the dependency check routine should be replaced with
+ * DEPT after. It should finally look like:
+ *
+ *
+ *
+ * As is:
+ *
+ * LOCKDEP
+ * +-----------------------------------------+
+ * | Lock usage correctness check | <-> locks
+ * | |
+ * | |
+ * | +-------------------------------------+ |
+ * | | Dependency check | |
+ * | | (by tracking lock acquisition order)| |
+ * | +-------------------------------------+ |
+ * | |
+ * +-----------------------------------------+
+ *
+ * DEPT
+ * +-----------------------------------------+
+ * | Dependency check | <-> waits/events
+ * | (by tracking wait and event context) |
+ * +-----------------------------------------+
+ *
+ *
+ *
+ * To be:
+ *
+ * LOCKDEP
+ * +-----------------------------------------+
+ * | Lock usage correctness check | <-> locks
+ * | |
+ * | |
+ * | (Request dependency check) |
+ * | T |
+ * +--------------------|--------------------+
+ * |
+ * DEPT V
+ * +-----------------------------------------+
+ * | Dependency check | <-> waits/events
+ * | (by tracking wait and event context) |
+ * +-----------------------------------------+
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/hash.h>
+#include <linux/dept.h>
+#include <linux/utsname.h>
+#include <linux/kernel.h>
+#include "dept_internal.h"
+
+static int dept_stop;
+static int dept_per_cpu_ready;
+
+static inline struct dept_task *dept_task(void)
+{
+ return ¤t->dept_task;
+}
+
+#define DEPT_READY_WARN (!oops_in_progress && !dept_task()->in_warning)
+
+/*
+ * Make all operations using DEPT_WARN_ON() fail on oops_in_progress and
+ * prevent warning message.
+ */
+#define DEPT_WARN_ON_ONCE(c) \
+ ({ \
+ int __ret = !!(c); \
+ \
+ if (likely(DEPT_READY_WARN)) { \
+ ++dept_task()->in_warning; \
+ WARN_ONCE(c, "DEPT_WARN_ON_ONCE: " #c); \
+ --dept_task()->in_warning; \
+ } \
+ __ret; \
+ })
+
+#define DEPT_WARN_ONCE(s...) \
+ ({ \
+ if (likely(DEPT_READY_WARN)) { \
+ ++dept_task()->in_warning; \
+ WARN_ONCE(1, "DEPT_WARN_ONCE: " s); \
+ --dept_task()->in_warning; \
+ } \
+ })
+
+#define DEPT_WARN_ON(c) \
+ ({ \
+ int __ret = !!(c); \
+ \
+ if (likely(DEPT_READY_WARN)) { \
+ ++dept_task()->in_warning; \
+ WARN(c, "DEPT_WARN_ON: " #c); \
+ --dept_task()->in_warning; \
+ } \
+ __ret; \
+ })
+
+#define DEPT_WARN(s...) \
+ ({ \
+ if (likely(DEPT_READY_WARN)) { \
+ ++dept_task()->in_warning; \
+ WARN(1, "DEPT_WARN: " s); \
+ --dept_task()->in_warning; \
+ } \
+ })
+
+#define DEPT_STOP(s...) \
+ ({ \
+ WRITE_ONCE(dept_stop, 1); \
+ if (likely(DEPT_READY_WARN)) { \
+ ++dept_task()->in_warning; \
+ WARN(1, "DEPT_STOP: " s); \
+ --dept_task()->in_warning; \
+ } \
+ })
+
+#define DEPT_INFO_ONCE(s...) pr_warn_once("DEPT_INFO_ONCE: " s)
+
+static arch_spinlock_t dept_spin = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+/*
+ * DEPT internal engine should be cautious in using outside functions
+ * e.g. printk at reporting since that kind of usage might cause
+ * untrackable deadlock.
+ */
+static atomic_t dept_outworld = ATOMIC_INIT(0);
+
+static void dept_outworld_enter(void)
+{
+ atomic_inc(&dept_outworld);
+}
+
+static void dept_outworld_exit(void)
+{
+ atomic_dec(&dept_outworld);
+}
+
+static bool dept_outworld_entered(void)
+{
+ return atomic_read(&dept_outworld);
+}
+
+static bool dept_lock(void)
+{
+ while (!arch_spin_trylock(&dept_spin))
+ if (unlikely(dept_outworld_entered()))
+ return false;
+ return true;
+}
+
+static void dept_unlock(void)
+{
+ arch_spin_unlock(&dept_spin);
+}
+
+enum bfs_ret {
+ BFS_CONTINUE,
+ BFS_DONE,
+ BFS_SKIP,
+};
+
+static bool before(unsigned int a, unsigned int b)
+{
+ return (int)(a - b) < 0;
+}
+
+static bool valid_stack(struct dept_stack *s)
+{
+ return s && s->nr > 0;
+}
+
+static bool valid_class(struct dept_class *c)
+{
+ return c->key;
+}
+
+static void invalidate_class(struct dept_class *c)
+{
+ c->key = 0UL;
+}
+
+static struct dept_ecxt *dep_e(struct dept_dep *d)
+{
+ return d->ecxt;
+}
+
+static struct dept_wait *dep_w(struct dept_dep *d)
+{
+ return d->wait;
+}
+
+static struct dept_class *dep_fc(struct dept_dep *d)
+{
+ return dep_e(d)->class;
+}
+
+static struct dept_class *dep_tc(struct dept_dep *d)
+{
+ return dep_w(d)->class;
+}
+
+static const char *irq_str(int irq)
+{
+ if (irq == DEPT_SIRQ)
+ return "softirq";
+ if (irq == DEPT_HIRQ)
+ return "hardirq";
+ return "(unknown)";
+}
+
+/*
+ * Dept doesn't work either when it's stopped by DEPT_STOP() or in a nmi
+ * context.
+ */
+static bool dept_working(void)
+{
+ return !READ_ONCE(dept_stop) && !in_nmi();
+}
+
+/*
+ * Even k == NULL is considered as a valid key because it would use
+ * &->map_key as the key in that case.
+ */
+struct dept_key __dept_no_validate__;
+static bool valid_key(struct dept_key *k)
+{
+ return &__dept_no_validate__ != k;
+}
+
+/*
+ * Pool
+ * =====================================================================
+ * DEPT maintains pools to provide objects in a safe way.
+ *
+ * 1) Static pool is used at the beginning of booting time.
+ * 2) Local pool is tried first before the static pool. Objects that
+ * have been freed will be placed.
+ */
+
+enum object_t {
+#define OBJECT(id, nr) OBJECT_##id,
+ #include "dept_object.h"
+#undef OBJECT
+ OBJECT_NR,
+};
+
+#define OBJECT(id, nr) \
+static struct dept_##id spool_##id[nr]; \
+static DEFINE_PER_CPU(struct llist_head, lpool_##id);
+ #include "dept_object.h"
+#undef OBJECT
+
+static struct dept_pool dept_pool[OBJECT_NR] = {
+#define OBJECT(id, nr) { \
+ .name = #id, \
+ .obj_sz = sizeof(struct dept_##id), \
+ .obj_nr = ATOMIC_INIT(nr), \
+ .node_off = offsetof(struct dept_##id, pool_node), \
+ .spool = spool_##id, \
+ .lpool = &lpool_##id, },
+ #include "dept_object.h"
+#undef OBJECT
+};
+
+/*
+ * Can use llist no matter whether CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG is
+ * enabled or not because NMI and other contexts in the same CPU never
+ * run inside of DEPT concurrently by preventing reentrance.
+ */
+static void *from_pool(enum object_t t)
+{
+ struct dept_pool *p;
+ struct llist_head *h;
+ struct llist_node *n;
+
+ /*
+ * llist_del_first() doesn't allow concurrent access e.g.
+ * between process and IRQ context.
+ */
+ if (DEPT_WARN_ON(!irqs_disabled()))
+ return NULL;
+
+ p = &dept_pool[t];
+
+ /*
+ * Try local pool first.
+ */
+ if (likely(dept_per_cpu_ready))
+ h = this_cpu_ptr(p->lpool);
+ else
+ h = &p->boot_pool;
+
+ n = llist_del_first(h);
+ if (n)
+ return (void *)n - p->node_off;
+
+ /*
+ * Try static pool.
+ */
+ if (atomic_read(&p->obj_nr) > 0) {
+ int idx = atomic_dec_return(&p->obj_nr);
+
+ if (idx >= 0)
+ return p->spool + (idx * p->obj_sz);
+ }
+
+ DEPT_INFO_ONCE("---------------------------------------------\n"
+ " Some of Dept internal resources are run out.\n"
+ " Dept might still work if the resources get freed.\n"
+ " However, the chances are Dept will suffer from\n"
+ " the lack from now. Needs to extend the internal\n"
+ " resource pools. Ask max.byungchul.park@gmail.com\n");
+ return NULL;
+}
+
+static void to_pool(void *o, enum object_t t)
+{
+ struct dept_pool *p = &dept_pool[t];
+ struct llist_head *h;
+
+ preempt_disable();
+ if (likely(dept_per_cpu_ready))
+ h = this_cpu_ptr(p->lpool);
+ else
+ h = &p->boot_pool;
+
+ llist_add(o + p->node_off, h);
+ preempt_enable();
+}
+
+#define OBJECT(id, nr) \
+static void (*ctor_##id)(struct dept_##id *a); \
+static void (*dtor_##id)(struct dept_##id *a); \
+static struct dept_##id *new_##id(void) \
+{ \
+ struct dept_##id *a; \
+ \
+ a = (struct dept_##id *)from_pool(OBJECT_##id); \
+ if (unlikely(!a)) \
+ return NULL; \
+ \
+ atomic_set(&a->ref, 1); \
+ \
+ if (ctor_##id) \
+ ctor_##id(a); \
+ \
+ return a; \
+} \
+ \
+static struct dept_##id *get_##id(struct dept_##id *a) \
+{ \
+ atomic_inc(&a->ref); \
+ return a; \
+} \
+ \
+static void put_##id(struct dept_##id *a) \
+{ \
+ if (!atomic_dec_return(&a->ref)) { \
+ if (dtor_##id) \
+ dtor_##id(a); \
+ to_pool(a, OBJECT_##id); \
+ } \
+} \
+ \
+static void del_##id(struct dept_##id *a) \
+{ \
+ put_##id(a); \
+} \
+ \
+static bool __maybe_unused id##_consumed(struct dept_##id *a) \
+{ \
+ return a && atomic_read(&a->ref) > 1; \
+}
+#include "dept_object.h"
+#undef OBJECT
+
+#define SET_CONSTRUCTOR(id, f) \
+static void (*ctor_##id)(struct dept_##id *a) = f
+
+static void initialize_dep(struct dept_dep *d)
+{
+ INIT_LIST_HEAD(&d->dep_node);
+ INIT_LIST_HEAD(&d->dep_rev_node);
+}
+SET_CONSTRUCTOR(dep, initialize_dep);
+
+static void initialize_class(struct dept_class *c)
+{
+ int i;
+
+ for (i = 0; i < DEPT_IRQS_NR; i++) {
+ struct dept_iecxt *ie = &c->iecxt[i];
+ struct dept_iwait *iw = &c->iwait[i];
+
+ ie->ecxt = NULL;
+ ie->enirq = i;
+ ie->staled = false;
+
+ iw->wait = NULL;
+ iw->irq = i;
+ iw->staled = false;
+ iw->touched = false;
+ }
+ c->bfs_gen = 0U;
+
+ INIT_LIST_HEAD(&c->all_node);
+ INIT_LIST_HEAD(&c->dep_head);
+ INIT_LIST_HEAD(&c->dep_rev_head);
+ INIT_LIST_HEAD(&c->bfs_node);
+}
+SET_CONSTRUCTOR(class, initialize_class);
+
+static void initialize_ecxt(struct dept_ecxt *e)
+{
+ int i;
+
+ for (i = 0; i < DEPT_IRQS_NR; i++) {
+ e->enirq_stack[i] = NULL;
+ e->enirq_ip[i] = 0UL;
+ }
+ e->ecxt_ip = 0UL;
+ e->ecxt_stack = NULL;
+ e->enirqf = 0UL;
+ e->event_ip = 0UL;
+ e->event_stack = NULL;
+}
+SET_CONSTRUCTOR(ecxt, initialize_ecxt);
+
+static void initialize_wait(struct dept_wait *w)
+{
+ int i;
+
+ for (i = 0; i < DEPT_IRQS_NR; i++) {
+ w->irq_stack[i] = NULL;
+ w->irq_ip[i] = 0UL;
+ }
+ w->wait_ip = 0UL;
+ w->wait_stack = NULL;
+ w->irqf = 0UL;
+}
+SET_CONSTRUCTOR(wait, initialize_wait);
+
+static void initialize_stack(struct dept_stack *s)
+{
+ s->nr = 0;
+}
+SET_CONSTRUCTOR(stack, initialize_stack);
+
+#define OBJECT(id, nr) \
+static void (*ctor_##id)(struct dept_##id *a);
+ #include "dept_object.h"
+#undef OBJECT
+
+#undef SET_CONSTRUCTOR
+
+#define SET_DESTRUCTOR(id, f) \
+static void (*dtor_##id)(struct dept_##id *a) = f
+
+static void destroy_dep(struct dept_dep *d)
+{
+ if (dep_e(d))
+ put_ecxt(dep_e(d));
+ if (dep_w(d))
+ put_wait(dep_w(d));
+}
+SET_DESTRUCTOR(dep, destroy_dep);
+
+static void destroy_ecxt(struct dept_ecxt *e)
+{
+ int i;
+
+ for (i = 0; i < DEPT_IRQS_NR; i++)
+ if (e->enirq_stack[i])
+ put_stack(e->enirq_stack[i]);
+ if (e->class)
+ put_class(e->class);
+ if (e->ecxt_stack)
+ put_stack(e->ecxt_stack);
+ if (e->event_stack)
+ put_stack(e->event_stack);
+}
+SET_DESTRUCTOR(ecxt, destroy_ecxt);
+
+static void destroy_wait(struct dept_wait *w)
+{
+ int i;
+
+ for (i = 0; i < DEPT_IRQS_NR; i++)
+ if (w->irq_stack[i])
+ put_stack(w->irq_stack[i]);
+ if (w->class)
+ put_class(w->class);
+ if (w->wait_stack)
+ put_stack(w->wait_stack);
+}
+SET_DESTRUCTOR(wait, destroy_wait);
+
+#define OBJECT(id, nr) \
+static void (*dtor_##id)(struct dept_##id *a);
+ #include "dept_object.h"
+#undef OBJECT
+
+#undef SET_DESTRUCTOR
+
+/*
+ * Caching and hashing
+ * =====================================================================
+ * DEPT makes use of caching and hashing to improve performance. Each
+ * object can be obtained in O(1) with its key.
+ *
+ * NOTE: Currently we assume all the objects in the hashs will never be
+ * removed. Implement it when needed.
+ */
+
+/*
+ * Some information might be lost but it's only for hashing key.
+ */
+static unsigned long mix(unsigned long a, unsigned long b)
+{
+ int halfbits = sizeof(unsigned long) * 8 / 2;
+ unsigned long halfmask = (1UL << halfbits) - 1UL;
+
+ return (a << halfbits) | (b & halfmask);
+}
+
+static bool cmp_dep(struct dept_dep *d1, struct dept_dep *d2)
+{
+ return dep_fc(d1)->key == dep_fc(d2)->key &&
+ dep_tc(d1)->key == dep_tc(d2)->key;
+}
+
+static unsigned long key_dep(struct dept_dep *d)
+{
+ return mix(dep_fc(d)->key, dep_tc(d)->key);
+}
+
+static bool cmp_class(struct dept_class *c1, struct dept_class *c2)
+{
+ return c1->key == c2->key;
+}
+
+static unsigned long key_class(struct dept_class *c)
+{
+ return c->key;
+}
+
+#define HASH(id, bits) \
+static struct hlist_head table_##id[1 << (bits)]; \
+ \
+static struct hlist_head *head_##id(struct dept_##id *a) \
+{ \
+ return table_##id + hash_long(key_##id(a), bits); \
+} \
+ \
+static struct dept_##id *hash_lookup_##id(struct dept_##id *a) \
+{ \
+ struct dept_##id *b; \
+ \
+ hlist_for_each_entry_rcu(b, head_##id(a), hash_node) \
+ if (cmp_##id(a, b)) \
+ return b; \
+ return NULL; \
+} \
+ \
+static void hash_add_##id(struct dept_##id *a) \
+{ \
+ get_##id(a); \
+ hlist_add_head_rcu(&a->hash_node, head_##id(a)); \
+} \
+ \
+static void hash_del_##id(struct dept_##id *a) \
+{ \
+ hlist_del_rcu(&a->hash_node); \
+ put_##id(a); \
+}
+#include "dept_hash.h"
+#undef HASH
+
+static struct dept_dep *lookup_dep(struct dept_class *fc,
+ struct dept_class *tc)
+{
+ struct dept_ecxt onetime_e = { .class = fc };
+ struct dept_wait onetime_w = { .class = tc };
+ struct dept_dep onetime_d = { .ecxt = &onetime_e,
+ .wait = &onetime_w };
+ return hash_lookup_dep(&onetime_d);
+}
+
+static struct dept_class *lookup_class(unsigned long key)
+{
+ struct dept_class onetime_c = { .key = key };
+
+ return hash_lookup_class(&onetime_c);
+}
+
+/*
+ * Report
+ * =====================================================================
+ * DEPT prints useful information to help debugging on detection of
+ * problematic dependency.
+ */
+
+static void print_ip_stack(unsigned long ip, struct dept_stack *s)
+{
+ if (ip)
+ print_ip_sym(KERN_WARNING, ip);
+
+#ifdef CONFIG_DEPT_DEBUG
+ if (!s)
+ pr_warn("stack is NULL.\n");
+ else if (!s->nr)
+ pr_warn("stack->nr is 0.\n");
+ if (s)
+ pr_warn("stack ref is %d.\n", atomic_read(&s->ref));
+#endif
+
+ if (valid_stack(s)) {
+ pr_warn("stacktrace:\n");
+ stack_trace_print(s->raw, s->nr, 5);
+ }
+
+ if (!ip && !valid_stack(s))
+ pr_warn("(N/A)\n");
+}
+
+#define print_spc(spc, fmt, ...) \
+ pr_warn("%*c" fmt, (spc) * 3, ' ', ##__VA_ARGS__)
+
+static void print_diagram(struct dept_dep *d)
+{
+ struct dept_ecxt *e = dep_e(d);
+ struct dept_wait *w = dep_w(d);
+ struct dept_class *fc = dep_fc(d);
+ struct dept_class *tc = dep_tc(d);
+ unsigned long irqf;
+ int irq;
+ bool firstline = true;
+ int spc = 1;
+ const char *w_fn = w->wait_fn ?: "(unknown)";
+ const char *e_fn = e->event_fn ?: "(unknown)";
+ const char *c_fn = e->ecxt_fn ?: "(unknown)";
+ const char *fc_n = fc->sched_map ? "<sched>" : (fc->name ?: "(unknown)");
+ const char *tc_n = tc->sched_map ? "<sched>" : (tc->name ?: "(unknown)");
+
+ irqf = e->enirqf & w->irqf;
+ for_each_set_bit(irq, &irqf, DEPT_IRQS_NR) {
+ if (!firstline)
+ pr_warn("\nor\n\n");
+ firstline = false;
+
+ print_spc(spc, "[S] %s(%s:%d)\n", c_fn, fc_n, fc->sub_id);
+ print_spc(spc, " <%s interrupt>\n", irq_str(irq));
+ print_spc(spc + 1, "[W] %s(%s:%d)\n", w_fn, tc_n, tc->sub_id);
+ print_spc(spc, "[E] %s(%s:%d)\n", e_fn, fc_n, fc->sub_id);
+ }
+
+ if (!irqf) {
+ print_spc(spc, "[S] %s(%s:%d)\n", c_fn, fc_n, fc->sub_id);
+ print_spc(spc, "[W] %s(%s:%d)\n", w_fn, tc_n, tc->sub_id);
+ print_spc(spc, "[E] %s(%s:%d)\n", e_fn, fc_n, fc->sub_id);
+ }
+}
+
+static void print_dep(struct dept_dep *d)
+{
+ struct dept_ecxt *e = dep_e(d);
+ struct dept_wait *w = dep_w(d);
+ struct dept_class *fc = dep_fc(d);
+ struct dept_class *tc = dep_tc(d);
+ unsigned long irqf;
+ int irq;
+ const char *w_fn = w->wait_fn ?: "(unknown)";
+ const char *e_fn = e->event_fn ?: "(unknown)";
+ const char *c_fn = e->ecxt_fn ?: "(unknown)";
+ const char *fc_n = fc->sched_map ? "<sched>" : (fc->name ?: "(unknown)");
+ const char *tc_n = tc->sched_map ? "<sched>" : (tc->name ?: "(unknown)");
+
+ irqf = e->enirqf & w->irqf;
+ for_each_set_bit(irq, &irqf, DEPT_IRQS_NR) {
+ pr_warn("%s has been enabled:\n", irq_str(irq));
+ print_ip_stack(e->enirq_ip[irq], e->enirq_stack[irq]);
+ pr_warn("\n");
+
+ pr_warn("[S] %s(%s:%d):\n", c_fn, fc_n, fc->sub_id);
+ print_ip_stack(e->ecxt_ip, e->ecxt_stack);
+ pr_warn("\n");
+
+ pr_warn("[W] %s(%s:%d) in %s context:\n",
+ w_fn, tc_n, tc->sub_id, irq_str(irq));
+ print_ip_stack(w->irq_ip[irq], w->irq_stack[irq]);
+ pr_warn("\n");
+
+ pr_warn("[E] %s(%s:%d):\n", e_fn, fc_n, fc->sub_id);
+ print_ip_stack(e->event_ip, e->event_stack);
+ }
+
+ if (!irqf) {
+ pr_warn("[S] %s(%s:%d):\n", c_fn, fc_n, fc->sub_id);
+ print_ip_stack(e->ecxt_ip, e->ecxt_stack);
+ pr_warn("\n");
+
+ pr_warn("[W] %s(%s:%d):\n", w_fn, tc_n, tc->sub_id);
+ print_ip_stack(w->wait_ip, w->wait_stack);
+ pr_warn("\n");
+
+ pr_warn("[E] %s(%s:%d):\n", e_fn, fc_n, fc->sub_id);
+ print_ip_stack(e->event_ip, e->event_stack);
+ }
+}
+
+static void save_current_stack(int skip);
+
+/*
+ * Print all classes in a circle.
+ */
+static void print_circle(struct dept_class *c)
+{
+ struct dept_class *fc = c->bfs_parent;
+ struct dept_class *tc = c;
+ int i;
+
+ dept_outworld_enter();
+ save_current_stack(6);
+
+ pr_warn("===================================================\n");
+ pr_warn("DEPT: Circular dependency has been detected.\n");
+ pr_warn("%s %.*s %s\n", init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version,
+ print_tainted());
+ pr_warn("---------------------------------------------------\n");
+ pr_warn("summary\n");
+ pr_warn("---------------------------------------------------\n");
+
+ if (fc == tc)
+ pr_warn("*** AA DEADLOCK ***\n\n");
+ else
+ pr_warn("*** DEADLOCK ***\n\n");
+
+ i = 0;
+ do {
+ struct dept_dep *d = lookup_dep(fc, tc);
+
+ pr_warn("context %c\n", 'A' + (i++));
+ print_diagram(d);
+ if (fc != c)
+ pr_warn("\n");
+
+ tc = fc;
+ fc = fc->bfs_parent;
+ } while (tc != c);
+
+ pr_warn("\n");
+ pr_warn("[S]: start of the event context\n");
+ pr_warn("[W]: the wait blocked\n");
+ pr_warn("[E]: the event not reachable\n");
+
+ i = 0;
+ do {
+ struct dept_dep *d = lookup_dep(fc, tc);
+
+ pr_warn("---------------------------------------------------\n");
+ pr_warn("context %c's detail\n", 'A' + i);
+ pr_warn("---------------------------------------------------\n");
+ pr_warn("context %c\n", 'A' + (i++));
+ print_diagram(d);
+ pr_warn("\n");
+ print_dep(d);
+
+ tc = fc;
+ fc = fc->bfs_parent;
+ } while (tc != c);
+
+ pr_warn("---------------------------------------------------\n");
+ pr_warn("information that might be helpful\n");
+ pr_warn("---------------------------------------------------\n");
+ dump_stack();
+
+ dept_outworld_exit();
+}
+
+/*
+ * BFS(Breadth First Search)
+ * =====================================================================
+ * Whenever a new dependency is added into the graph, search the graph
+ * for a new circular dependency.
+ */
+
+struct bfs_ops {
+ void (*bfs_init)(void *, void *, void **);
+ void (*extend)(struct list_head *, void *);
+ void *(*dequeue)(struct list_head *);
+ enum bfs_ret (*callback)(void *, void *, void **);
+};
+
+static unsigned int bfs_gen;
+
+/*
+ * NOTE: Must be called with dept_lock held.
+ */
+static void bfs(void *root, struct bfs_ops *ops, void *in, void **out)
+{
+ LIST_HEAD(q);
+ enum bfs_ret ret;
+
+ if (DEPT_WARN_ON(!ops || !ops->bfs_init || !ops->extend ||
+ !ops->dequeue || !ops->callback))
+ return;
+
+ /*
+ * Avoid zero bfs_gen.
+ */
+ bfs_gen = bfs_gen + 1 ?: 1;
+ ops->bfs_init(root, in, out);
+
+ ret = ops->callback(root, in, out);
+ if (ret != BFS_CONTINUE)
+ return;
+
+ ops->extend(&q, root);
+ while (!list_empty(&q)) {
+ void *node = ops->dequeue(&q);
+
+ if (ret == BFS_DONE)
+ continue;
+
+ ret = ops->callback(node, in, out);
+ if (ret == BFS_CONTINUE)
+ ops->extend(&q, node);
+ }
+}
+
+/*
+ * Main operations
+ * =====================================================================
+ * Add dependencies - Each new dependency is added into the graph and
+ * checked if it forms a circular dependency.
+ *
+ * Track waits - Waits are queued into the ring buffer for later use to
+ * generate appropriate dependencies with cross-event.
+ *
+ * Track event contexts(ecxt) - Event contexts are pushed into local
+ * stack for later use to generate appropriate dependencies with waits.
+ */
+
+static unsigned long cur_enirqf(void);
+static int cur_irq(void);
+static unsigned int cur_ctxt_id(void);
+
+static struct dept_iecxt *iecxt(struct dept_class *c, int irq)
+{
+ return &c->iecxt[irq];
+}
+
+static struct dept_iwait *iwait(struct dept_class *c, int irq)
+{
+ return &c->iwait[irq];
+}
+
+static void stale_iecxt(struct dept_iecxt *ie)
+{
+ if (ie->ecxt)
+ put_ecxt(ie->ecxt);
+
+ WRITE_ONCE(ie->ecxt, NULL);
+ WRITE_ONCE(ie->staled, true);
+}
+
+static void set_iecxt(struct dept_iecxt *ie, struct dept_ecxt *e)
+{
+ /*
+ * ->ecxt will never be updated once getting set until the class
+ * gets removed.
+ */
+ if (ie->ecxt)
+ DEPT_WARN_ON(1);
+ else
+ WRITE_ONCE(ie->ecxt, get_ecxt(e));
+}
+
+static void stale_iwait(struct dept_iwait *iw)
+{
+ if (iw->wait)
+ put_wait(iw->wait);
+
+ WRITE_ONCE(iw->wait, NULL);
+ WRITE_ONCE(iw->staled, true);
+}
+
+static void set_iwait(struct dept_iwait *iw, struct dept_wait *w)
+{
+ /*
+ * ->wait will never be updated once getting set until the class
+ * gets removed.
+ */
+ if (iw->wait)
+ DEPT_WARN_ON(1);
+ else
+ WRITE_ONCE(iw->wait, get_wait(w));
+
+ iw->touched = true;
+}
+
+static void touch_iwait(struct dept_iwait *iw)
+{
+ iw->touched = true;
+}
+
+static void untouch_iwait(struct dept_iwait *iw)
+{
+ iw->touched = false;
+}
+
+static struct dept_stack *get_current_stack(void)
+{
+ struct dept_stack *s = dept_task()->stack;
+
+ return s ? get_stack(s) : NULL;
+}
+
+static void prepare_current_stack(void)
+{
+ DEPT_WARN_ON(dept_task()->stack);
+
+ dept_task()->stack = new_stack();
+}
+
+static void save_current_stack(int skip)
+{
+ struct dept_stack *s = dept_task()->stack;
+
+ if (!s)
+ return;
+
+ if (valid_stack(s))
+ return;
+
+ s->nr = stack_trace_save(s->raw, DEPT_MAX_STACK_ENTRY, skip);
+}
+
+static void finish_current_stack(void)
+{
+ struct dept_stack *s = dept_task()->stack;
+
+ /*
+ * Fill the struct dept_stack with a valid stracktrace if it has
+ * been referred at least once.
+ */
+ if (stack_consumed(s))
+ save_current_stack(2);
+
+ dept_task()->stack = NULL;
+
+ /*
+ * Actual deletion will happen at put_stack() if the stack has
+ * been referred.
+ */
+ if (s)
+ del_stack(s);
+}
+
+/*
+ * FIXME: For now, disable LOCKDEP while DEPT is working.
+ *
+ * Both LOCKDEP and DEPT report it on a deadlock detection using
+ * printk taking the risk of another deadlock that might be caused by
+ * locks of console or printk between inside and outside of them.
+ *
+ * For DEPT, it's no problem since multiple reports are allowed. But it
+ * would be a bad idea for LOCKDEP since it will stop even on a singe
+ * report. So we need to prevent LOCKDEP from its reporting the risk
+ * DEPT would take when reporting something.
+ */
+#include <linux/lockdep.h>
+
+void noinstr dept_off(void)
+{
+ dept_task()->recursive++;
+ lockdep_off();
+}
+
+void noinstr dept_on(void)
+{
+ lockdep_on();
+ dept_task()->recursive--;
+}
+
+static unsigned long dept_enter(void)
+{
+ unsigned long flags;
+
+ flags = arch_local_irq_save();
+ dept_off();
+ prepare_current_stack();
+ return flags;
+}
+
+static void dept_exit(unsigned long flags)
+{
+ finish_current_stack();
+ dept_on();
+ arch_local_irq_restore(flags);
+}
+
+static unsigned long dept_enter_recursive(void)
+{
+ unsigned long flags;
+
+ flags = arch_local_irq_save();
+ return flags;
+}
+
+static void dept_exit_recursive(unsigned long flags)
+{
+ arch_local_irq_restore(flags);
+}
+
+/*
+ * NOTE: Must be called with dept_lock held.
+ */
+static struct dept_dep *__add_dep(struct dept_ecxt *e,
+ struct dept_wait *w)
+{
+ struct dept_dep *d;
+
+ if (DEPT_WARN_ON(!valid_class(e->class)))
+ return NULL;
+
+ if (DEPT_WARN_ON(!valid_class(w->class)))
+ return NULL;
+
+ if (lookup_dep(e->class, w->class))
+ return NULL;
+
+ d = new_dep();
+ if (unlikely(!d))
+ return NULL;
+
+ d->ecxt = get_ecxt(e);
+ d->wait = get_wait(w);
+
+ /*
+ * Add the dependency into hash and graph.
+ */
+ hash_add_dep(d);
+ list_add(&d->dep_node, &dep_fc(d)->dep_head);
+ list_add(&d->dep_rev_node, &dep_tc(d)->dep_rev_head);
+ return d;
+}
+
+static void bfs_init_check_dl(void *node, void *in, void **out)
+{
+ struct dept_class *root = (struct dept_class *)node;
+ struct dept_dep *new = (struct dept_dep *)in;
+
+ root->bfs_gen = bfs_gen;
+ dep_tc(new)->bfs_parent = dep_fc(new);
+}
+
+static void bfs_extend_dep(struct list_head *h, void *node)
+{
+ struct dept_class *cur = (struct dept_class *)node;
+ struct dept_dep *d;
+
+ list_for_each_entry(d, &cur->dep_head, dep_node) {
+ struct dept_class *next = dep_tc(d);
+
+ if (bfs_gen == next->bfs_gen)
+ continue;
+ next->bfs_parent = cur;
+ next->bfs_gen = bfs_gen;
+ list_add_tail(&next->bfs_node, h);
+ }
+}
+
+static void *bfs_dequeue_dep(struct list_head *h)
+{
+ struct dept_class *c;
+
+ DEPT_WARN_ON(list_empty(h));
+
+ c = list_first_entry(h, struct dept_class, bfs_node);
+ list_del(&c->bfs_node);
+ return c;
+}
+
+static enum bfs_ret cb_check_dl(void *node, void *in, void **out)
+{
+ struct dept_class *cur = (struct dept_class *)node;
+ struct dept_dep *new = (struct dept_dep *)in;
+
+ if (cur == dep_fc(new)) {
+ print_circle(dep_tc(new));
+ return BFS_DONE;
+ }
+
+ return BFS_CONTINUE;
+}
+
+/*
+ * This function is actually in charge of reporting.
+ */
+static void check_dl_bfs(struct dept_dep *d)
+{
+ struct bfs_ops ops = {
+ .bfs_init = bfs_init_check_dl,
+ .extend = bfs_extend_dep,
+ .dequeue = bfs_dequeue_dep,
+ .callback = cb_check_dl,
+ };
+
+ bfs((void *)dep_tc(d), &ops, (void *)d, NULL);
+}
+
+static void bfs_init_dep(void *node, void *in, void **out)
+{
+ struct dept_class *root = (struct dept_class *)node;
+
+ root->bfs_gen = bfs_gen;
+}
+
+static void bfs_extend_dep_rev(struct list_head *h, void *node)
+{
+ struct dept_class *cur = (struct dept_class *)node;
+ struct dept_dep *d;
+
+ list_for_each_entry(d, &cur->dep_rev_head, dep_rev_node) {
+ struct dept_class *next = dep_fc(d);
+
+ if (bfs_gen == next->bfs_gen)
+ continue;
+ next->bfs_parent = cur;
+ next->bfs_gen = bfs_gen;
+ list_add_tail(&next->bfs_node, h);
+ }
+}
+
+static enum bfs_ret cb_find_iw(void *node, void *in, void **out)
+{
+ struct dept_class *cur = (struct dept_class *)node;
+ int irq = *(int *)in;
+ struct dept_iwait *iw;
+
+ if (DEPT_WARN_ON(!out))
+ return BFS_DONE;
+
+ iw = iwait(cur, irq);
+
+ /*
+ * If any parent's ->wait was set, then the children would've
+ * been touched.
+ */
+ if (!iw->touched)
+ return BFS_SKIP;
+
+ if (!iw->wait)
+ return BFS_CONTINUE;
+
+ *out = iw;
+ return BFS_DONE;
+}
+
+static struct dept_iwait *find_iw_bfs(struct dept_class *c, int irq)
+{
+ struct dept_iwait *iw = iwait(c, irq);
+ struct dept_iwait *found = NULL;
+ struct bfs_ops ops = {
+ .bfs_init = bfs_init_dep,
+ .extend = bfs_extend_dep_rev,
+ .dequeue = bfs_dequeue_dep,
+ .callback = cb_find_iw,
+ };
+
+ bfs((void *)c, &ops, (void *)&irq, (void **)&found);
+
+ if (found)
+ return found;
+
+ untouch_iwait(iw);
+ return NULL;
+}
+
+static enum bfs_ret cb_touch_iw_find_ie(void *node, void *in, void **out)
+{
+ struct dept_class *cur = (struct dept_class *)node;
+ int irq = *(int *)in;
+ struct dept_iecxt *ie = iecxt(cur, irq);
+ struct dept_iwait *iw = iwait(cur, irq);
+
+ if (DEPT_WARN_ON(!out))
+ return BFS_DONE;
+
+ touch_iwait(iw);
+
+ if (!ie->ecxt)
+ return BFS_CONTINUE;
+ if (!*out)
+ *out = ie;
+
+ /*
+ * Do touch_iwait() all the way.
+ */
+ return BFS_CONTINUE;
+}
+
+static struct dept_iecxt *touch_iw_find_ie_bfs(struct dept_class *c,
+ int irq)
+{
+ struct dept_iecxt *found = NULL;
+ struct bfs_ops ops = {
+ .bfs_init = bfs_init_dep,
+ .extend = bfs_extend_dep,
+ .dequeue = bfs_dequeue_dep,
+ .callback = cb_touch_iw_find_ie,
+ };
+
+ bfs((void *)c, &ops, (void *)&irq, (void **)&found);
+ return found;
+}
+
+/*
+ * Should be called with dept_lock held.
+ */
+static void __add_idep(struct dept_iecxt *ie, struct dept_iwait *iw)
+{
+ struct dept_dep *new;
+
+ /*
+ * There's nothing to do.
+ */
+ if (!ie || !iw || !ie->ecxt || !iw->wait)
+ return;
+
+ new = __add_dep(ie->ecxt, iw->wait);
+
+ /*
+ * Deadlock detected. Let check_dl_bfs() report it.
+ */
+ if (new) {
+ check_dl_bfs(new);
+ stale_iecxt(ie);
+ stale_iwait(iw);
+ }
+
+ /*
+ * If !new, it would be the case of lack of object resource.
+ * Just let it go and get checked by other chances. Retrying is
+ * meaningless in that case.
+ */
+}
+
+static void set_check_iecxt(struct dept_class *c, int irq,
+ struct dept_ecxt *e)
+{
+ struct dept_iecxt *ie = iecxt(c, irq);
+
+ set_iecxt(ie, e);
+ __add_idep(ie, find_iw_bfs(c, irq));
+}
+
+static void set_check_iwait(struct dept_class *c, int irq,
+ struct dept_wait *w)
+{
+ struct dept_iwait *iw = iwait(c, irq);
+
+ set_iwait(iw, w);
+ __add_idep(touch_iw_find_ie_bfs(c, irq), iw);
+}
+
+static void add_iecxt(struct dept_class *c, int irq, struct dept_ecxt *e,
+ bool stack)
+{
+ /*
+ * This access is safe since we ensure e->class has set locally.
+ */
+ struct dept_task *dt = dept_task();
+ struct dept_iecxt *ie = iecxt(c, irq);
+
+ if (DEPT_WARN_ON(!valid_class(c)))
+ return;
+
+ if (unlikely(READ_ONCE(ie->staled)))
+ return;
+
+ /*
+ * Skip add_iecxt() if ie->ecxt has ever been set at least once.
+ * Which means it has a valid ->ecxt or been staled.
+ */
+ if (READ_ONCE(ie->ecxt))
+ return;
+
+ if (unlikely(!dept_lock()))
+ return;
+
+ if (unlikely(ie->staled))
+ goto unlock;
+ if (ie->ecxt)
+ goto unlock;
+
+ e->enirqf |= (1UL << irq);
+
+ /*
+ * Should be NULL since it's the first time that these
+ * enirq_{ip,stack}[irq] have ever set.
+ */
+ DEPT_WARN_ON(e->enirq_ip[irq]);
+ DEPT_WARN_ON(e->enirq_stack[irq]);
+
+ e->enirq_ip[irq] = dt->enirq_ip[irq];
+ e->enirq_stack[irq] = stack ? get_current_stack() : NULL;
+
+ set_check_iecxt(c, irq, e);
+unlock:
+ dept_unlock();
+}
+
+static void add_iwait(struct dept_class *c, int irq, struct dept_wait *w)
+{
+ struct dept_iwait *iw = iwait(c, irq);
+
+ if (DEPT_WARN_ON(!valid_class(c)))
+ return;
+
+ if (unlikely(READ_ONCE(iw->staled)))
+ return;
+
+ /*
+ * Skip add_iwait() if iw->wait has ever been set at least once.
+ * Which means it has a valid ->wait or been staled.
+ */
+ if (READ_ONCE(iw->wait))
+ return;
+
+ if (unlikely(!dept_lock()))
+ return;
+
+ if (unlikely(iw->staled))
+ goto unlock;
+ if (iw->wait)
+ goto unlock;
+
+ w->irqf |= (1UL << irq);
+
+ /*
+ * Should be NULL since it's the first time that these
+ * irq_{ip,stack}[irq] have ever set.
+ */
+ DEPT_WARN_ON(w->irq_ip[irq]);
+ DEPT_WARN_ON(w->irq_stack[irq]);
+
+ w->irq_ip[irq] = w->wait_ip;
+ w->irq_stack[irq] = get_current_stack();
+
+ set_check_iwait(c, irq, w);
+unlock:
+ dept_unlock();
+}
+
+static struct dept_wait_hist *hist(int pos)
+{
+ struct dept_task *dt = dept_task();
+
+ return dt->wait_hist + (pos % DEPT_MAX_WAIT_HIST);
+}
+
+static int hist_pos_next(void)
+{
+ struct dept_task *dt = dept_task();
+
+ return dt->wait_hist_pos % DEPT_MAX_WAIT_HIST;
+}
+
+static void hist_advance(void)
+{
+ struct dept_task *dt = dept_task();
+
+ dt->wait_hist_pos++;
+ dt->wait_hist_pos %= DEPT_MAX_WAIT_HIST;
+}
+
+static struct dept_wait_hist *new_hist(void)
+{
+ struct dept_wait_hist *wh = hist(hist_pos_next());
+
+ hist_advance();
+ return wh;
+}
+
+static void add_hist(struct dept_wait *w, unsigned int wg, unsigned int ctxt_id)
+{
+ struct dept_wait_hist *wh = new_hist();
+
+ if (likely(wh->wait))
+ put_wait(wh->wait);
+
+ wh->wait = get_wait(w);
+ wh->wgen = wg;
+ wh->ctxt_id = ctxt_id;
+}
+
+/*
+ * Should be called after setting up e's iecxt and w's iwait.
+ */
+static void add_dep(struct dept_ecxt *e, struct dept_wait *w)
+{
+ struct dept_class *fc = e->class;
+ struct dept_class *tc = w->class;
+ struct dept_dep *d;
+ int i;
+
+ if (lookup_dep(fc, tc))
+ return;
+
+ if (unlikely(!dept_lock()))
+ return;
+
+ /*
+ * __add_dep() will lookup_dep() again with lock held.
+ */
+ d = __add_dep(e, w);
+ if (d) {
+ check_dl_bfs(d);
+
+ for (i = 0; i < DEPT_IRQS_NR; i++) {
+ struct dept_iwait *fiw = iwait(fc, i);
+ struct dept_iecxt *found_ie;
+ struct dept_iwait *found_iw;
+
+ /*
+ * '->touched == false' guarantees there's no
+ * parent that has been set ->wait.
+ */
+ if (!fiw->touched)
+ continue;
+
+ /*
+ * find_iw_bfs() will untouch the iwait if
+ * not found.
+ */
+ found_iw = find_iw_bfs(fc, i);
+
+ if (!found_iw)
+ continue;
+
+ found_ie = touch_iw_find_ie_bfs(tc, i);
+ __add_idep(found_ie, found_iw);
+ }
+ }
+ dept_unlock();
+}
+
+static atomic_t wgen = ATOMIC_INIT(1);
+
+static int next_wgen(void)
+{
+ /*
+ * Avoid zero wgen.
+ */
+ return atomic_inc_return(&wgen) ?: atomic_inc_return(&wgen);
+}
+
+static void add_wait(struct dept_class *c, unsigned long ip,
+ const char *w_fn, int sub_l, bool sched_sleep)
+{
+ struct dept_task *dt = dept_task();
+ struct dept_wait *w;
+ unsigned int wg;
+ int irq;
+ int i;
+
+ if (DEPT_WARN_ON(!valid_class(c)))
+ return;
+
+ w = new_wait();
+ if (unlikely(!w))
+ return;
+
+ WRITE_ONCE(w->class, get_class(c));
+ w->wait_ip = ip;
+ w->wait_fn = w_fn;
+ w->wait_stack = get_current_stack();
+ w->sched_sleep = sched_sleep;
+
+ irq = cur_irq();
+ if (irq < DEPT_IRQS_NR)
+ add_iwait(c, irq, w);
+
+ /*
+ * Avoid adding dependency between user aware nested ecxt and
+ * wait.
+ */
+ for (i = dt->ecxt_held_pos - 1; i >= 0; i--) {
+ struct dept_ecxt_held *eh;
+
+ eh = dt->ecxt_held + i;
+
+ /*
+ * the case of invalid key'ed one
+ */
+ if (!eh->ecxt)
+ continue;
+
+ if (eh->ecxt->class != c || eh->sub_l == sub_l)
+ add_dep(eh->ecxt, w);
+ }
+
+ wg = next_wgen();
+ add_hist(w, wg, cur_ctxt_id());
+
+ del_wait(w);
+}
+
+static struct dept_ecxt_held *add_ecxt(struct dept_map *m,
+ struct dept_class *c, unsigned long ip, const char *c_fn,
+ const char *e_fn, int sub_l)
+{
+ struct dept_task *dt = dept_task();
+ struct dept_ecxt_held *eh;
+ struct dept_ecxt *e;
+ unsigned long irqf;
+ unsigned int wg;
+ int irq;
+
+ if (DEPT_WARN_ON(!valid_class(c)))
+ return NULL;
+
+ if (DEPT_WARN_ON_ONCE(dt->ecxt_held_pos >= DEPT_MAX_ECXT_HELD))
+ return NULL;
+
+ wg = next_wgen();
+ if (m->nocheck) {
+ eh = dt->ecxt_held + (dt->ecxt_held_pos++);
+ eh->ecxt = NULL;
+ eh->map = m;
+ eh->class = get_class(c);
+ eh->wgen = wg;
+ eh->sub_l = sub_l;
+
+ return eh;
+ }
+
+ e = new_ecxt();
+ if (unlikely(!e))
+ return NULL;
+
+ e->class = get_class(c);
+ e->ecxt_ip = ip;
+ e->ecxt_stack = ip ? get_current_stack() : NULL;
+ e->event_fn = e_fn;
+ e->ecxt_fn = c_fn;
+
+ eh = dt->ecxt_held + (dt->ecxt_held_pos++);
+ eh->ecxt = get_ecxt(e);
+ eh->map = m;
+ eh->class = get_class(c);
+ eh->wgen = wg;
+ eh->sub_l = sub_l;
+
+ irqf = cur_enirqf();
+ for_each_set_bit(irq, &irqf, DEPT_IRQS_NR)
+ add_iecxt(c, irq, e, false);
+
+ del_ecxt(e);
+ return eh;
+}
+
+static int find_ecxt_pos(struct dept_map *m, struct dept_class *c,
+ bool newfirst)
+{
+ struct dept_task *dt = dept_task();
+ int i;
+
+ if (newfirst) {
+ for (i = dt->ecxt_held_pos - 1; i >= 0; i--) {
+ struct dept_ecxt_held *eh;
+
+ eh = dt->ecxt_held + i;
+ if (eh->map == m && eh->class == c)
+ return i;
+ }
+ } else {
+ for (i = 0; i < dt->ecxt_held_pos; i++) {
+ struct dept_ecxt_held *eh;
+
+ eh = dt->ecxt_held + i;
+ if (eh->map == m && eh->class == c)
+ return i;
+ }
+ }
+ return -1;
+}
+
+static bool pop_ecxt(struct dept_map *m, struct dept_class *c)
+{
+ struct dept_task *dt = dept_task();
+ int pos;
+ int i;
+
+ pos = find_ecxt_pos(m, c, true);
+ if (pos == -1)
+ return false;
+
+ if (dt->ecxt_held[pos].class)
+ put_class(dt->ecxt_held[pos].class);
+
+ if (dt->ecxt_held[pos].ecxt)
+ put_ecxt(dt->ecxt_held[pos].ecxt);
+
+ dt->ecxt_held_pos--;
+
+ for (i = pos; i < dt->ecxt_held_pos; i++)
+ dt->ecxt_held[i] = dt->ecxt_held[i + 1];
+ return true;
+}
+
+static bool good_hist(struct dept_wait_hist *wh, unsigned int wg)
+{
+ return wh->wait != NULL && before(wg, wh->wgen);
+}
+
+/*
+ * Binary-search the ring buffer for the earliest valid wait.
+ */
+static int find_hist_pos(unsigned int wg)
+{
+ int oldest;
+ int l;
+ int r;
+ int pos;
+
+ oldest = hist_pos_next();
+ if (unlikely(good_hist(hist(oldest), wg))) {
+ DEPT_INFO_ONCE("Need to expand the ring buffer.\n");
+ return oldest;
+ }
+
+ l = oldest + 1;
+ r = oldest + DEPT_MAX_WAIT_HIST - 1;
+ for (pos = (l + r) / 2; l <= r; pos = (l + r) / 2) {
+ struct dept_wait_hist *p = hist(pos - 1);
+ struct dept_wait_hist *wh = hist(pos);
+
+ if (!good_hist(p, wg) && good_hist(wh, wg))
+ return pos % DEPT_MAX_WAIT_HIST;
+ if (good_hist(wh, wg))
+ r = pos - 1;
+ else
+ l = pos + 1;
+ }
+ return -1;
+}
+
+static void do_event(struct dept_map *m, struct dept_map *real_m,
+ struct dept_class *c, unsigned int wg, unsigned long ip,
+ const char *e_fn)
+{
+ struct dept_task *dt = dept_task();
+ struct dept_wait_hist *wh;
+ struct dept_ecxt_held *eh;
+ unsigned int ctxt_id;
+ int end;
+ int pos;
+ int i;
+
+ if (DEPT_WARN_ON(!valid_class(c)))
+ return;
+
+ if (m->nocheck)
+ return;
+
+ /*
+ * The event was triggered before wait.
+ */
+ if (!wg)
+ return;
+
+ /*
+ * If an ecxt for this map exists, let the ecxt work for this
+ * event and do not proceed it in do_event().
+ */
+ if (find_ecxt_pos(real_m, c, false) != -1)
+ return;
+ eh = add_ecxt(m, c, 0UL, NULL, e_fn, 0);
+
+ if (!eh)
+ return;
+
+ if (DEPT_WARN_ON(!eh->ecxt))
+ goto out;
+
+ eh->ecxt->event_ip = ip;
+ eh->ecxt->event_stack = get_current_stack();
+
+ pos = find_hist_pos(wg);
+ if (pos == -1)
+ goto out;
+
+ ctxt_id = cur_ctxt_id();
+ end = hist_pos_next();
+ end = end > pos ? end : end + DEPT_MAX_WAIT_HIST;
+ for (wh = hist(pos); pos < end; wh = hist(++pos)) {
+ if (dt->in_sched && wh->wait->sched_sleep)
+ continue;
+
+ if (wh->ctxt_id == ctxt_id)
+ add_dep(eh->ecxt, wh->wait);
+ }
+
+ for (i = 0; i < DEPT_IRQS_NR; i++) {
+ struct dept_ecxt *e;
+
+ if (before(dt->wgen_enirq[i], wg))
+ continue;
+
+ e = eh->ecxt;
+ add_iecxt(e->class, i, e, false);
+ }
+out:
+ /*
+ * Pop ecxt that temporarily has been added to handle this event.
+ */
+ pop_ecxt(m, c);
+}
+
+static void del_dep_rcu(struct rcu_head *rh)
+{
+ struct dept_dep *d = container_of(rh, struct dept_dep, rh);
+
+ preempt_disable();
+ del_dep(d);
+ preempt_enable();
+}
+
+/*
+ * NOTE: Must be called with dept_lock held.
+ */
+static void disconnect_class(struct dept_class *c)
+{
+ struct dept_dep *d, *n;
+ int i;
+
+ list_for_each_entry_safe(d, n, &c->dep_head, dep_node) {
+ list_del_rcu(&d->dep_node);
+ list_del_rcu(&d->dep_rev_node);
+ hash_del_dep(d);
+ call_rcu(&d->rh, del_dep_rcu);
+ }
+
+ list_for_each_entry_safe(d, n, &c->dep_rev_head, dep_rev_node) {
+ list_del_rcu(&d->dep_node);
+ list_del_rcu(&d->dep_rev_node);
+ hash_del_dep(d);
+ call_rcu(&d->rh, del_dep_rcu);
+ }
+
+ for (i = 0; i < DEPT_IRQS_NR; i++) {
+ stale_iecxt(iecxt(c, i));
+ stale_iwait(iwait(c, i));
+ }
+}
+
+/*
+ * Context control
+ * =====================================================================
+ * Whether a wait is in {hard,soft}-IRQ context or whether
+ * {hard,soft}-IRQ has been enabled on the way to an event is very
+ * important to check dependency. All those things should be tracked.
+ */
+
+static unsigned long cur_enirqf(void)
+{
+ struct dept_task *dt = dept_task();
+ int he = dt->hardirqs_enabled;
+ int se = dt->softirqs_enabled;
+
+ if (he)
+ return DEPT_HIRQF | (se ? DEPT_SIRQF : 0UL);
+ return 0UL;
+}
+
+static int cur_irq(void)
+{
+ if (lockdep_softirq_context(current))
+ return DEPT_SIRQ;
+ if (lockdep_hardirq_context())
+ return DEPT_HIRQ;
+ return DEPT_IRQS_NR;
+}
+
+static unsigned int cur_ctxt_id(void)
+{
+ struct dept_task *dt = dept_task();
+ int irq = cur_irq();
+
+ /*
+ * Normal process context
+ */
+ if (irq == DEPT_IRQS_NR)
+ return 0U;
+
+ return dt->irq_id[irq] | (1UL << irq);
+}
+
+static void enirq_transition(int irq)
+{
+ struct dept_task *dt = dept_task();
+ int i;
+
+ /*
+ * IRQ can cut in on the way to the event. Used for cross-event
+ * detection.
+ *
+ * wait context event context(ecxt)
+ * ------------ -------------------
+ * wait event
+ * UPDATE wgen
+ * observe IRQ enabled
+ * UPDATE wgen
+ * keep the wgen locally
+ *
+ * on the event
+ * check the wgen kept
+ */
+
+ dt->wgen_enirq[irq] = next_wgen();
+
+ for (i = dt->ecxt_held_pos - 1; i >= 0; i--) {
+ struct dept_ecxt_held *eh;
+ struct dept_ecxt *e;
+
+ eh = dt->ecxt_held + i;
+ e = eh->ecxt;
+ if (e)
+ add_iecxt(e->class, irq, e, true);
+ }
+}
+
+static void dept_enirq(unsigned long ip)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long irqf = cur_enirqf();
+ int irq;
+ unsigned long flags;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ /*
+ * IRQ ON/OFF transition might happen while Dept is working.
+ * We cannot handle recursive entrance. Just ignore it.
+ * Only transitions outside of Dept will be considered.
+ */
+ if (dt->recursive)
+ return;
+
+ flags = dept_enter();
+
+ for_each_set_bit(irq, &irqf, DEPT_IRQS_NR) {
+ dt->enirq_ip[irq] = ip;
+ enirq_transition(irq);
+ }
+
+ dept_exit(flags);
+}
+
+void dept_softirqs_on_ip(unsigned long ip)
+{
+ /*
+ * Assumes that it's called with IRQ disabled so that accessing
+ * current's fields is not racy.
+ */
+ dept_task()->softirqs_enabled = true;
+ dept_enirq(ip);
+}
+
+void dept_hardirqs_on(void)
+{
+ /*
+ * Assumes that it's called with IRQ disabled so that accessing
+ * current's fields is not racy.
+ */
+ dept_task()->hardirqs_enabled = true;
+ dept_enirq(_RET_IP_);
+}
+
+void dept_softirqs_off(void)
+{
+ /*
+ * Assumes that it's called with IRQ disabled so that accessing
+ * current's fields is not racy.
+ */
+ dept_task()->softirqs_enabled = false;
+}
+
+void dept_hardirqs_off(void)
+{
+ /*
+ * Assumes that it's called with IRQ disabled so that accessing
+ * current's fields is not racy.
+ */
+ dept_task()->hardirqs_enabled = false;
+}
+
+/*
+ * Ensure it's the outmost softirq context.
+ */
+void dept_softirq_enter(void)
+{
+ struct dept_task *dt = dept_task();
+
+ dt->irq_id[DEPT_SIRQ] += 1UL << DEPT_IRQS_NR;
+}
+
+/*
+ * Ensure it's the outmost hardirq context.
+ */
+void dept_hardirq_enter(void)
+{
+ struct dept_task *dt = dept_task();
+
+ dt->irq_id[DEPT_HIRQ] += 1UL << DEPT_IRQS_NR;
+}
+
+void dept_sched_enter(void)
+{
+ dept_task()->in_sched = true;
+}
+
+void dept_sched_exit(void)
+{
+ dept_task()->in_sched = false;
+}
+
+/*
+ * Exposed APIs
+ * =====================================================================
+ */
+
+static void clean_classes_cache(struct dept_key *k)
+{
+ int i;
+
+ for (i = 0; i < DEPT_MAX_SUBCLASSES_CACHE; i++) {
+ if (!READ_ONCE(k->classes[i]))
+ continue;
+
+ WRITE_ONCE(k->classes[i], NULL);
+ }
+}
+
+/*
+ * Assume we don't have to consider race with the map when
+ * dept_map_init() is called.
+ */
+void dept_map_init(struct dept_map *m, struct dept_key *k, int sub_u,
+ const char *n)
+{
+ unsigned long flags;
+
+ if (unlikely(!dept_working())) {
+ m->nocheck = true;
+ return;
+ }
+
+ if (DEPT_WARN_ON(sub_u < 0)) {
+ m->nocheck = true;
+ return;
+ }
+
+ if (DEPT_WARN_ON(sub_u >= DEPT_MAX_SUBCLASSES_USR)) {
+ m->nocheck = true;
+ return;
+ }
+
+ /*
+ * Allow recursive entrance.
+ */
+ flags = dept_enter_recursive();
+
+ clean_classes_cache(&m->map_key);
+
+ m->keys = k;
+ m->sub_u = sub_u;
+ m->name = n;
+ m->wgen = 0U;
+ m->nocheck = !valid_key(k);
+
+ dept_exit_recursive(flags);
+}
+EXPORT_SYMBOL_GPL(dept_map_init);
+
+/*
+ * Assume we don't have to consider race with the map when
+ * dept_map_reinit() is called.
+ */
+void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u,
+ const char *n)
+{
+ unsigned long flags;
+
+ if (unlikely(!dept_working())) {
+ m->nocheck = true;
+ return;
+ }
+
+ /*
+ * Allow recursive entrance.
+ */
+ flags = dept_enter_recursive();
+
+ if (k) {
+ clean_classes_cache(&m->map_key);
+ m->keys = k;
+ m->nocheck = !valid_key(k);
+ }
+
+ if (sub_u >= 0 && sub_u < DEPT_MAX_SUBCLASSES_USR)
+ m->sub_u = sub_u;
+
+ if (n)
+ m->name = n;
+
+ m->wgen = 0U;
+
+ dept_exit_recursive(flags);
+}
+EXPORT_SYMBOL_GPL(dept_map_reinit);
+
+void dept_map_copy(struct dept_map *to, struct dept_map *from)
+{
+ if (unlikely(!dept_working())) {
+ to->nocheck = true;
+ return;
+ }
+
+ *to = *from;
+
+ /*
+ * XXX: 'to' might be in a stack or something. Using the address
+ * in a stack segment as a key is meaningless. Just ignore the
+ * case for now.
+ */
+ if (!to->keys) {
+ to->nocheck = true;
+ return;
+ }
+
+ /*
+ * Since the class cache can be modified concurrently we could
+ * observe half pointers (64bit arch using 32bit copy
+ * instructions). Therefore clear the caches and take the
+ * performance hit.
+ */
+ clean_classes_cache(&to->map_key);
+}
+
+static LIST_HEAD(dept_classes);
+
+static bool within(const void *addr, void *start, unsigned long size)
+{
+ return addr >= start && addr < start + size;
+}
+
+void dept_free_range(void *start, unsigned int sz)
+{
+ struct dept_task *dt = dept_task();
+ struct dept_class *c, *n;
+ unsigned long flags;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive) {
+ DEPT_STOP("Failed to successfully free Dept objects.\n");
+ return;
+ }
+
+ flags = dept_enter();
+
+ /*
+ * dept_free_range() should not fail.
+ *
+ * FIXME: Should be fixed if dept_free_range() causes deadlock
+ * with dept_lock().
+ */
+ while (unlikely(!dept_lock()))
+ cpu_relax();
+
+ list_for_each_entry_safe(c, n, &dept_classes, all_node) {
+ if (!within((void *)c->key, start, sz) &&
+ !within(c->name, start, sz))
+ continue;
+
+ hash_del_class(c);
+ disconnect_class(c);
+ list_del(&c->all_node);
+ invalidate_class(c);
+
+ /*
+ * Actual deletion will happen on the rcu callback
+ * that has been added in disconnect_class().
+ */
+ del_class(c);
+ }
+ dept_unlock();
+ dept_exit(flags);
+
+ /*
+ * Wait until even lockless hash_lookup_class() for the class
+ * returns NULL.
+ */
+ might_sleep();
+ synchronize_rcu();
+}
+
+static int sub_id(struct dept_map *m, int e)
+{
+ return (m ? m->sub_u : 0) + e * DEPT_MAX_SUBCLASSES_USR;
+}
+
+static struct dept_class *check_new_class(struct dept_key *local,
+ struct dept_key *k, int sub_id,
+ const char *n, bool sched_map)
+{
+ struct dept_class *c = NULL;
+
+ if (DEPT_WARN_ON(sub_id >= DEPT_MAX_SUBCLASSES))
+ return NULL;
+
+ if (DEPT_WARN_ON(!k))
+ return NULL;
+
+ /*
+ * XXX: Assume that users prevent the map from using if any of
+ * the cached keys has been invalidated. If not, the cache,
+ * local->classes should not be used because it would be racy
+ * with class deletion.
+ */
+ if (local && sub_id < DEPT_MAX_SUBCLASSES_CACHE)
+ c = READ_ONCE(local->classes[sub_id]);
+
+ if (c)
+ return c;
+
+ c = lookup_class((unsigned long)k->base + sub_id);
+ if (c)
+ goto caching;
+
+ if (unlikely(!dept_lock()))
+ return NULL;
+
+ c = lookup_class((unsigned long)k->base + sub_id);
+ if (unlikely(c))
+ goto unlock;
+
+ c = new_class();
+ if (unlikely(!c))
+ goto unlock;
+
+ c->name = n;
+ c->sched_map = sched_map;
+ c->sub_id = sub_id;
+ c->key = (unsigned long)(k->base + sub_id);
+ hash_add_class(c);
+ list_add(&c->all_node, &dept_classes);
+unlock:
+ dept_unlock();
+caching:
+ if (local && sub_id < DEPT_MAX_SUBCLASSES_CACHE)
+ WRITE_ONCE(local->classes[sub_id], c);
+
+ return c;
+}
+
+/*
+ * Called between dept_enter() and dept_exit().
+ */
+static void __dept_wait(struct dept_map *m, unsigned long w_f,
+ unsigned long ip, const char *w_fn, int sub_l,
+ bool sched_sleep, bool sched_map)
+{
+ int e;
+
+ /*
+ * Be as conservative as possible. In case of multiple waits for
+ * a single dept_map, we are going to keep only the last wait's
+ * wgen for simplicity - keeping all wgens seems overengineering.
+ *
+ * Of course, it might cause missing some dependencies that
+ * would rarely, probably never, happen but it helps avoid
+ * false positive reports.
+ */
+ for_each_set_bit(e, &w_f, DEPT_MAX_SUBCLASSES_EVT) {
+ struct dept_class *c;
+ struct dept_key *k;
+
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k,
+ sub_id(m, e), m->name, sched_map);
+ if (!c)
+ continue;
+
+ add_wait(c, ip, w_fn, sub_l, sched_sleep);
+ }
+}
+
+/*
+ * Called between dept_enter() and dept_exit().
+ */
+static void __dept_event(struct dept_map *m, struct dept_map *real_m,
+ unsigned long e_f, unsigned long ip, const char *e_fn,
+ bool sched_map)
+{
+ struct dept_class *c;
+ struct dept_key *k;
+ int e;
+
+ e = find_first_bit(&e_f, DEPT_MAX_SUBCLASSES_EVT);
+
+ if (DEPT_WARN_ON(e >= DEPT_MAX_SUBCLASSES_EVT))
+ return;
+
+ /*
+ * An event is an event. If the caller passed more than single
+ * event, then warn it and handle the event corresponding to
+ * the first bit anyway.
+ */
+ DEPT_WARN_ON(1UL << e != e_f);
+
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k, sub_id(m, e), m->name, sched_map);
+
+ if (c)
+ do_event(m, real_m, c, READ_ONCE(m->wgen), ip, e_fn);
+}
+
+void dept_wait(struct dept_map *m, unsigned long w_f,
+ unsigned long ip, const char *w_fn, int sub_l)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive)
+ return;
+
+ if (m->nocheck)
+ return;
+
+ flags = dept_enter();
+
+ __dept_wait(m, w_f, ip, w_fn, sub_l, false, false);
+
+ dept_exit(flags);
+}
+EXPORT_SYMBOL_GPL(dept_wait);
+
+void dept_stage_wait(struct dept_map *m, struct dept_key *k,
+ unsigned long ip, const char *w_fn)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (m && m->nocheck)
+ return;
+
+ /*
+ * Either m or k should be passed. Which means Dept relies on
+ * either its own map or the caller's position in the code when
+ * determining its class.
+ */
+ if (DEPT_WARN_ON(!m && !k))
+ return;
+
+ /*
+ * Allow recursive entrance.
+ */
+ flags = dept_enter_recursive();
+
+ /*
+ * Ensure the outmost dept_stage_wait() works.
+ */
+ if (dt->stage_m.keys)
+ goto exit;
+
+ arch_spin_lock(&dt->stage_lock);
+ if (m) {
+ dt->stage_m = *m;
+ dt->stage_real_m = m;
+
+ /*
+ * Ensure dt->stage_m.keys != NULL and it works with the
+ * map's map_key, not stage_m's one when ->keys == NULL.
+ */
+ if (!m->keys)
+ dt->stage_m.keys = &m->map_key;
+ } else {
+ dt->stage_m.name = w_fn;
+ dt->stage_sched_map = true;
+ dt->stage_real_m = &dt->stage_m;
+ }
+
+ /*
+ * dept_map_reinit() includes WRITE_ONCE(->wgen, 0U) that
+ * effectively disables the map just in case real sleep won't
+ * happen. dept_request_event_wait_commit() will enable it.
+ */
+ dept_map_reinit(&dt->stage_m, k, -1, NULL);
+
+ dt->stage_w_fn = w_fn;
+ dt->stage_ip = ip;
+ arch_spin_unlock(&dt->stage_lock);
+exit:
+ dept_exit_recursive(flags);
+}
+EXPORT_SYMBOL_GPL(dept_stage_wait);
+
+static void __dept_clean_stage(struct dept_task *dt)
+{
+ memset(&dt->stage_m, 0x0, sizeof(struct dept_map));
+ dt->stage_real_m = NULL;
+ dt->stage_sched_map = false;
+ dt->stage_w_fn = NULL;
+ dt->stage_ip = 0UL;
+}
+
+void dept_clean_stage(void)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ /*
+ * Allow recursive entrance.
+ */
+ flags = dept_enter_recursive();
+ arch_spin_lock(&dt->stage_lock);
+ __dept_clean_stage(dt);
+ arch_spin_unlock(&dt->stage_lock);
+ dept_exit_recursive(flags);
+}
+EXPORT_SYMBOL_GPL(dept_clean_stage);
+
+/*
+ * Always called from __schedule().
+ */
+void dept_request_event_wait_commit(void)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+ unsigned int wg;
+ unsigned long ip;
+ const char *w_fn;
+ bool sched_map;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ /*
+ * It's impossible that __schedule() is called while Dept is
+ * working that already disabled IRQ at the entrance.
+ */
+ if (DEPT_WARN_ON(dt->recursive))
+ return;
+
+ flags = dept_enter();
+
+ arch_spin_lock(&dt->stage_lock);
+
+ /*
+ * Checks if current has staged a wait.
+ */
+ if (!dt->stage_m.keys) {
+ arch_spin_unlock(&dt->stage_lock);
+ goto exit;
+ }
+
+ w_fn = dt->stage_w_fn;
+ ip = dt->stage_ip;
+ sched_map = dt->stage_sched_map;
+
+ wg = next_wgen();
+ WRITE_ONCE(dt->stage_m.wgen, wg);
+ arch_spin_unlock(&dt->stage_lock);
+
+ __dept_wait(&dt->stage_m, 1UL, ip, w_fn, 0, true, sched_map);
+exit:
+ dept_exit(flags);
+}
+
+/*
+ * Always called from try_to_wake_up().
+ */
+void dept_ttwu_stage_wait(struct task_struct *requestor, unsigned long ip)
+{
+ struct dept_task *dt = dept_task();
+ struct dept_task *dt_req = &requestor->dept_task;
+ unsigned long flags;
+ struct dept_map m;
+ struct dept_map *real_m;
+ bool sched_map;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive)
+ return;
+
+ flags = dept_enter();
+
+ arch_spin_lock(&dt_req->stage_lock);
+
+ /*
+ * Serializing is unnecessary as long as it always comes from
+ * try_to_wake_up().
+ */
+ m = dt_req->stage_m;
+ sched_map = dt_req->stage_sched_map;
+ real_m = dt_req->stage_real_m;
+ __dept_clean_stage(dt_req);
+ arch_spin_unlock(&dt_req->stage_lock);
+
+ /*
+ * ->stage_m.keys should not be NULL if it's in use. Should
+ * make sure that it's not NULL when staging a valid map.
+ */
+ if (!m.keys)
+ goto exit;
+
+ __dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map);
+exit:
+ dept_exit(flags);
+}
+
+/*
+ * Modifies the latest ecxt corresponding to m and e_f.
+ */
+void dept_map_ecxt_modify(struct dept_map *m, unsigned long e_f,
+ struct dept_key *new_k, unsigned long new_e_f,
+ unsigned long new_ip, const char *new_c_fn,
+ const char *new_e_fn, int new_sub_l)
+{
+ struct dept_task *dt = dept_task();
+ struct dept_ecxt_held *eh;
+ struct dept_class *c;
+ struct dept_key *k;
+ unsigned long flags;
+ int pos = -1;
+ int new_e;
+ int e;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ /*
+ * XXX: Couldn't handle re-enterance cases. Ignore it for now.
+ */
+ if (dt->recursive)
+ return;
+
+ /*
+ * Should go ahead no matter whether ->nocheck == true or not
+ * because ->nocheck value can be changed within the ecxt area
+ * delimitated by dept_ecxt_enter() and dept_ecxt_exit().
+ */
+
+ flags = dept_enter();
+
+ for_each_set_bit(e, &e_f, DEPT_MAX_SUBCLASSES_EVT) {
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k,
+ sub_id(m, e), m->name, false);
+ if (!c)
+ continue;
+
+ /*
+ * When it found an ecxt for any event in e_f, done.
+ */
+ pos = find_ecxt_pos(m, c, true);
+ if (pos != -1)
+ break;
+ }
+
+ if (unlikely(pos == -1))
+ goto exit;
+
+ eh = dt->ecxt_held + pos;
+ new_sub_l = new_sub_l >= 0 ? new_sub_l : eh->sub_l;
+
+ new_e = find_first_bit(&new_e_f, DEPT_MAX_SUBCLASSES_EVT);
+
+ if (new_e < DEPT_MAX_SUBCLASSES_EVT)
+ /*
+ * Let it work with the first bit anyway.
+ */
+ DEPT_WARN_ON(1UL << new_e != new_e_f);
+ else
+ new_e = e;
+
+ pop_ecxt(m, c);
+
+ /*
+ * Apply the key to the map.
+ */
+ if (new_k)
+ dept_map_reinit(m, new_k, -1, NULL);
+
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k, sub_id(m, new_e), m->name, false);
+
+ if (c && add_ecxt(m, c, new_ip, new_c_fn, new_e_fn, new_sub_l))
+ goto exit;
+
+ /*
+ * Successfully pop_ecxt()ed but failed to add_ecxt().
+ */
+ dt->missing_ecxt++;
+exit:
+ dept_exit(flags);
+}
+EXPORT_SYMBOL_GPL(dept_map_ecxt_modify);
+
+void dept_ecxt_enter(struct dept_map *m, unsigned long e_f, unsigned long ip,
+ const char *c_fn, const char *e_fn, int sub_l)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+ struct dept_class *c;
+ struct dept_key *k;
+ int e;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive) {
+ dt->missing_ecxt++;
+ return;
+ }
+
+ /*
+ * Should go ahead no matter whether ->nocheck == true or not
+ * because ->nocheck value can be changed within the ecxt area
+ * delimitated by dept_ecxt_enter() and dept_ecxt_exit().
+ */
+
+ flags = dept_enter();
+
+ e = find_first_bit(&e_f, DEPT_MAX_SUBCLASSES_EVT);
+
+ if (e >= DEPT_MAX_SUBCLASSES_EVT)
+ goto missing_ecxt;
+
+ /*
+ * An event is an event. If the caller passed more than single
+ * event, then warn it and handle the event corresponding to
+ * the first bit anyway.
+ */
+ DEPT_WARN_ON(1UL << e != e_f);
+
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k, sub_id(m, e), m->name, false);
+
+ if (c && add_ecxt(m, c, ip, c_fn, e_fn, sub_l))
+ goto exit;
+missing_ecxt:
+ dt->missing_ecxt++;
+exit:
+ dept_exit(flags);
+}
+EXPORT_SYMBOL_GPL(dept_ecxt_enter);
+
+bool dept_ecxt_holding(struct dept_map *m, unsigned long e_f)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+ bool ret = false;
+ int e;
+
+ if (unlikely(!dept_working()))
+ return false;
+
+ if (dt->recursive)
+ return false;
+
+ flags = dept_enter();
+
+ for_each_set_bit(e, &e_f, DEPT_MAX_SUBCLASSES_EVT) {
+ struct dept_class *c;
+ struct dept_key *k;
+
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k,
+ sub_id(m, e), m->name, false);
+ if (!c)
+ continue;
+
+ if (find_ecxt_pos(m, c, true) != -1) {
+ ret = true;
+ break;
+ }
+ }
+
+ dept_exit(flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dept_ecxt_holding);
+
+void dept_request_event(struct dept_map *m)
+{
+ unsigned long flags;
+ unsigned int wg;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (m->nocheck)
+ return;
+
+ /*
+ * Allow recursive entrance.
+ */
+ flags = dept_enter_recursive();
+
+ wg = next_wgen();
+ WRITE_ONCE(m->wgen, wg);
+
+ dept_exit_recursive(flags);
+}
+EXPORT_SYMBOL_GPL(dept_request_event);
+
+void dept_event(struct dept_map *m, unsigned long e_f,
+ unsigned long ip, const char *e_fn)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (m->nocheck)
+ return;
+
+ if (dt->recursive) {
+ /*
+ * Dept won't work with this even though an event
+ * context has been asked. Don't make it confused at
+ * handling the event. Disable it until the next.
+ */
+ WRITE_ONCE(m->wgen, 0U);
+ return;
+ }
+
+ flags = dept_enter();
+
+ __dept_event(m, m, e_f, ip, e_fn, false);
+
+ /*
+ * Keep the map diabled until the next sleep.
+ */
+ WRITE_ONCE(m->wgen, 0U);
+
+ dept_exit(flags);
+}
+EXPORT_SYMBOL_GPL(dept_event);
+
+void dept_ecxt_exit(struct dept_map *m, unsigned long e_f,
+ unsigned long ip)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+ int e;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive) {
+ dt->missing_ecxt--;
+ return;
+ }
+
+ /*
+ * Should go ahead no matter whether ->nocheck == true or not
+ * because ->nocheck value can be changed within the ecxt area
+ * delimitated by dept_ecxt_enter() and dept_ecxt_exit().
+ */
+
+ flags = dept_enter();
+
+ for_each_set_bit(e, &e_f, DEPT_MAX_SUBCLASSES_EVT) {
+ struct dept_class *c;
+ struct dept_key *k;
+
+ k = m->keys ?: &m->map_key;
+ c = check_new_class(&m->map_key, k,
+ sub_id(m, e), m->name, false);
+ if (!c)
+ continue;
+
+ /*
+ * When it found an ecxt for any event in e_f, done.
+ */
+ if (pop_ecxt(m, c))
+ goto exit;
+ }
+
+ dt->missing_ecxt--;
+exit:
+ dept_exit(flags);
+}
+EXPORT_SYMBOL_GPL(dept_ecxt_exit);
+
+void dept_task_exit(struct task_struct *t)
+{
+ struct dept_task *dt = &t->dept_task;
+ int i;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ raw_local_irq_disable();
+
+ if (dt->stack) {
+ put_stack(dt->stack);
+ dt->stack = NULL;
+ }
+
+ for (i = 0; i < dt->ecxt_held_pos; i++) {
+ if (dt->ecxt_held[i].class) {
+ put_class(dt->ecxt_held[i].class);
+ dt->ecxt_held[i].class = NULL;
+ }
+ if (dt->ecxt_held[i].ecxt) {
+ put_ecxt(dt->ecxt_held[i].ecxt);
+ dt->ecxt_held[i].ecxt = NULL;
+ }
+ }
+
+ for (i = 0; i < DEPT_MAX_WAIT_HIST; i++) {
+ if (dt->wait_hist[i].wait) {
+ put_wait(dt->wait_hist[i].wait);
+ dt->wait_hist[i].wait = NULL;
+ }
+ }
+
+ dt->task_exit = true;
+ dept_off();
+
+ raw_local_irq_enable();
+}
+
+void dept_task_init(struct task_struct *t)
+{
+ memset(&t->dept_task, 0x0, sizeof(struct dept_task));
+ t->dept_task.stage_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+}
+
+void dept_key_init(struct dept_key *k)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+ int sub_id;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive) {
+ DEPT_STOP("Key initialization fails.\n");
+ return;
+ }
+
+ flags = dept_enter();
+
+ clean_classes_cache(k);
+
+ /*
+ * dept_key_init() should not fail.
+ *
+ * FIXME: Should be fixed if dept_key_init() causes deadlock
+ * with dept_lock().
+ */
+ while (unlikely(!dept_lock()))
+ cpu_relax();
+
+ for (sub_id = 0; sub_id < DEPT_MAX_SUBCLASSES; sub_id++) {
+ struct dept_class *c;
+
+ c = lookup_class((unsigned long)k->base + sub_id);
+ if (!c)
+ continue;
+
+ DEPT_STOP("The class(%s/%d) has not been removed.\n",
+ c->name, sub_id);
+ break;
+ }
+
+ dept_unlock();
+ dept_exit(flags);
+}
+EXPORT_SYMBOL_GPL(dept_key_init);
+
+void dept_key_destroy(struct dept_key *k)
+{
+ struct dept_task *dt = dept_task();
+ unsigned long flags;
+ int sub_id;
+
+ if (unlikely(!dept_working()))
+ return;
+
+ if (dt->recursive == 1 && dt->task_exit) {
+ /*
+ * Need to allow to go ahead in this case where
+ * ->recursive has been set to 1 by dept_off() in
+ * dept_task_exit() and ->task_exit has been set to
+ * true in dept_task_exit().
+ */
+ } else if (dt->recursive) {
+ DEPT_STOP("Key destroying fails.\n");
+ return;
+ }
+
+ flags = dept_enter();
+
+ /*
+ * dept_key_destroy() should not fail.
+ *
+ * FIXME: Should be fixed if dept_key_destroy() causes deadlock
+ * with dept_lock().
+ */
+ while (unlikely(!dept_lock()))
+ cpu_relax();
+
+ for (sub_id = 0; sub_id < DEPT_MAX_SUBCLASSES; sub_id++) {
+ struct dept_class *c;
+
+ c = lookup_class((unsigned long)k->base + sub_id);
+ if (!c)
+ continue;
+
+ hash_del_class(c);
+ disconnect_class(c);
+ list_del(&c->all_node);
+ invalidate_class(c);
+
+ /*
+ * Actual deletion will happen on the rcu callback
+ * that has been added in disconnect_class().
+ */
+ del_class(c);
+ }
+
+ dept_unlock();
+ dept_exit(flags);
+
+ /*
+ * Wait until even lockless hash_lookup_class() for the class
+ * returns NULL.
+ */
+ might_sleep();
+ synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(dept_key_destroy);
+
+static void move_llist(struct llist_head *to, struct llist_head *from)
+{
+ struct llist_node *first = llist_del_all(from);
+ struct llist_node *last = first;
+
+ if (!first)
+ return;
+
+ while (llist_next(last))
+ last = llist_next(last);
+ llist_add_batch(first, last, to);
+}
+
+static void migrate_per_cpu_pool(void)
+{
+ const int boot_cpu = 0;
+ int i;
+
+ /*
+ * The boot CPU has been using the temporal local pool so far.
+ * From now on that per_cpu areas have been ready, use the
+ * per_cpu local pool instead.
+ */
+ DEPT_WARN_ON(smp_processor_id() != boot_cpu);
+ for (i = 0; i < OBJECT_NR; i++) {
+ struct llist_head *from;
+ struct llist_head *to;
+
+ from = &dept_pool[i].boot_pool;
+ to = per_cpu_ptr(dept_pool[i].lpool, boot_cpu);
+ move_llist(to, from);
+ }
+}
+
+#define B2KB(B) ((B) / 1024)
+
+/*
+ * Should be called after setup_per_cpu_areas() and before no non-boot
+ * CPUs have been on.
+ */
+void __init dept_init(void)
+{
+ size_t mem_total = 0;
+
+ local_irq_disable();
+ dept_per_cpu_ready = 1;
+ migrate_per_cpu_pool();
+ local_irq_enable();
+
+#define HASH(id, bits) BUILD_BUG_ON(1 << (bits) <= 0);
+ #include "dept_hash.h"
+#undef HASH
+#define OBJECT(id, nr) mem_total += sizeof(struct dept_##id) * nr;
+ #include "dept_object.h"
+#undef OBJECT
+#define HASH(id, bits) mem_total += sizeof(struct hlist_head) * (1 << (bits));
+ #include "dept_hash.h"
+#undef HASH
+
+ pr_info("DEPendency Tracker: Copyright (c) 2020 LG Electronics, Inc., Byungchul Park\n");
+ pr_info("... DEPT_MAX_STACK_ENTRY: %d\n", DEPT_MAX_STACK_ENTRY);
+ pr_info("... DEPT_MAX_WAIT_HIST : %d\n", DEPT_MAX_WAIT_HIST);
+ pr_info("... DEPT_MAX_ECXT_HELD : %d\n", DEPT_MAX_ECXT_HELD);
+ pr_info("... DEPT_MAX_SUBCLASSES : %d\n", DEPT_MAX_SUBCLASSES);
+#define OBJECT(id, nr) \
+ pr_info("... memory used by %s: %zu KB\n", \
+ #id, B2KB(sizeof(struct dept_##id) * nr));
+ #include "dept_object.h"
+#undef OBJECT
+#define HASH(id, bits) \
+ pr_info("... hash list head used by %s: %zu KB\n", \
+ #id, B2KB(sizeof(struct hlist_head) * (1 << (bits))));
+ #include "dept_hash.h"
+#undef HASH
+ pr_info("... total memory used by objects and hashs: %zu KB\n", B2KB(mem_total));
+ pr_info("... per task memory footprint: %zu bytes\n", sizeof(struct dept_task));
+}
diff --git a/kernel/dependency/dept_hash.h b/kernel/dependency/dept_hash.h
new file mode 100644
index 000000000000..fd85aab1fdfb
--- /dev/null
+++ b/kernel/dependency/dept_hash.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * HASH(id, bits)
+ *
+ * id : Id for the object of struct dept_##id.
+ * bits: 1UL << bits is the hash table size.
+ */
+
+HASH(dep, 12)
+HASH(class, 12)
diff --git a/kernel/dependency/dept_internal.h b/kernel/dependency/dept_internal.h
new file mode 100644
index 000000000000..9b28398fecfd
--- /dev/null
+++ b/kernel/dependency/dept_internal.h
@@ -0,0 +1,283 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Dept(DEPendency Tracker) - runtime dependency tracker internal header
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ * Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ * Copyright (c) 2024 SK hynix, Inc., Byungchul Park
+ */
+
+#ifndef __DEPT_INTERNAL_H
+#define __DEPT_INTERNAL_H
+
+#ifdef CONFIG_DEPT
+#include <linux/dept.h>
+#include <linux/percpu.h>
+#include <linux/llist.h>
+#include <linux/types.h>
+
+struct dept_pool {
+ const char *name;
+
+ /*
+ * object size
+ */
+ size_t obj_sz;
+
+ /*
+ * the number of the static array
+ */
+ atomic_t obj_nr;
+
+ /*
+ * offset of ->pool_node
+ */
+ size_t node_off;
+
+ /*
+ * pointer to the pool
+ */
+ void *spool;
+ struct llist_head boot_pool;
+ struct llist_head __percpu *lpool;
+};
+
+struct dept_ecxt;
+struct dept_iecxt {
+ struct dept_ecxt *ecxt;
+ int enirq;
+ /*
+ * for preventing to add a new ecxt
+ */
+ bool staled;
+};
+
+struct dept_wait;
+struct dept_iwait {
+ struct dept_wait *wait;
+ int irq;
+ /*
+ * for preventing to add a new wait
+ */
+ bool staled;
+ bool touched;
+};
+
+struct dept_class {
+ union {
+ struct llist_node pool_node;
+ struct {
+ /*
+ * reference counter for object management
+ */
+ atomic_t ref;
+
+ /*
+ * unique information about the class
+ */
+ const char *name;
+ unsigned long key;
+ int sub_id;
+
+ /*
+ * for BFS
+ */
+ unsigned int bfs_gen;
+ struct dept_class *bfs_parent;
+ struct list_head bfs_node;
+
+ /*
+ * for hashing this object
+ */
+ struct hlist_node hash_node;
+
+ /*
+ * for linking all classes
+ */
+ struct list_head all_node;
+
+ /*
+ * for associating its dependencies
+ */
+ struct list_head dep_head;
+ struct list_head dep_rev_head;
+
+ /*
+ * for tracking IRQ dependencies
+ */
+ struct dept_iecxt iecxt[DEPT_IRQS_NR];
+ struct dept_iwait iwait[DEPT_IRQS_NR];
+
+ /*
+ * classified by a map embedded in task_struct,
+ * not an explicit map
+ */
+ bool sched_map;
+ };
+ };
+};
+
+struct dept_stack {
+ union {
+ struct llist_node pool_node;
+ struct {
+ /*
+ * reference counter for object management
+ */
+ atomic_t ref;
+
+ /*
+ * backtrace entries
+ */
+ unsigned long raw[DEPT_MAX_STACK_ENTRY];
+ int nr;
+ };
+ };
+};
+
+struct dept_ecxt {
+ union {
+ struct llist_node pool_node;
+ struct {
+ /*
+ * reference counter for object management
+ */
+ atomic_t ref;
+
+ /*
+ * function that entered to this ecxt
+ */
+ const char *ecxt_fn;
+
+ /*
+ * event function
+ */
+ const char *event_fn;
+
+ /*
+ * associated class
+ */
+ struct dept_class *class;
+
+ /*
+ * flag indicating which IRQ has been
+ * enabled within the event context
+ */
+ unsigned long enirqf;
+
+ /*
+ * where the IRQ-enabled happened
+ */
+ unsigned long enirq_ip[DEPT_IRQS_NR];
+ struct dept_stack *enirq_stack[DEPT_IRQS_NR];
+
+ /*
+ * where the event context started
+ */
+ unsigned long ecxt_ip;
+ struct dept_stack *ecxt_stack;
+
+ /*
+ * where the event triggered
+ */
+ unsigned long event_ip;
+ struct dept_stack *event_stack;
+ };
+ };
+};
+
+struct dept_wait {
+ union {
+ struct llist_node pool_node;
+ struct {
+ /*
+ * reference counter for object management
+ */
+ atomic_t ref;
+
+ /*
+ * function causing this wait
+ */
+ const char *wait_fn;
+
+ /*
+ * the associated class
+ */
+ struct dept_class *class;
+
+ /*
+ * which IRQ the wait was placed in
+ */
+ unsigned long irqf;
+
+ /*
+ * where the IRQ wait happened
+ */
+ unsigned long irq_ip[DEPT_IRQS_NR];
+ struct dept_stack *irq_stack[DEPT_IRQS_NR];
+
+ /*
+ * where the wait happened
+ */
+ unsigned long wait_ip;
+ struct dept_stack *wait_stack;
+
+ /*
+ * whether this wait is for commit in scheduler
+ */
+ bool sched_sleep;
+ };
+ };
+};
+
+struct dept_dep {
+ union {
+ struct llist_node pool_node;
+ struct {
+ /*
+ * reference counter for object management
+ */
+ atomic_t ref;
+
+ /*
+ * key data of dependency
+ */
+ struct dept_ecxt *ecxt;
+ struct dept_wait *wait;
+
+ /*
+ * This object can be referred without dept_lock
+ * held but with IRQ disabled, e.g. for hash
+ * lookup. So deferred deletion is needed.
+ */
+ struct rcu_head rh;
+
+ /*
+ * for hashing this object
+ */
+ struct hlist_node hash_node;
+
+ /*
+ * for linking to a class object
+ */
+ struct list_head dep_node;
+ struct list_head dep_rev_node;
+ };
+ };
+};
+
+struct dept_hash {
+ /*
+ * hash table
+ */
+ struct hlist_head *table;
+
+ /*
+ * size of the table e.i. 2^bits
+ */
+ int bits;
+};
+
+#endif
+#endif /* __DEPT_INTERNAL_H */
diff --git a/kernel/dependency/dept_object.h b/kernel/dependency/dept_object.h
new file mode 100644
index 000000000000..0b7eb16fe9fb
--- /dev/null
+++ b/kernel/dependency/dept_object.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * OBJECT(id, nr)
+ *
+ * id: Id for the object of struct dept_##id.
+ * nr: # of the object that should be kept in the pool.
+ */
+
+OBJECT(dep, 1024 * 8)
+OBJECT(class, 1024 * 8)
+OBJECT(stack, 1024 * 32)
+OBJECT(ecxt, 1024 * 16)
+OBJECT(wait, 1024 * 32)
diff --git a/kernel/exit.c b/kernel/exit.c
index 4dc1918db67b..99c848b58177 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1013,6 +1013,7 @@ void __noreturn do_exit(long code)
exit_tasks_rcu_finish();
lockdep_free_task(tsk);
+ dept_task_exit(tsk);
do_task_dead();
}
diff --git a/kernel/fork.c b/kernel/fork.c
index 25d243718048..07c87562d11d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -106,6 +106,7 @@
#include <linux/pidfs.h>
#include <linux/tick.h>
#include <linux/unwind_deferred.h>
+#include <linux/dept.h>
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
@@ -2130,6 +2131,7 @@ __latent_entropy struct task_struct *copy_process(
p->pagefault_disabled = 0;
lockdep_init_task(p);
+ dept_task_init(p);
p->blocked_on = NULL; /* not blocked yet */
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 7b3ec2fa6e7c..03ed63f2adf0 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1375,12 +1375,14 @@ static void free_mod_mem(struct module *mod)
/* Free lock-classes; relies on the preceding sync_rcu(). */
lockdep_free_key_range(mod_mem->base, mod_mem->size);
+ dept_free_range(mod_mem->base, mod_mem->size);
if (mod_mem->size)
module_memory_free(mod, type);
}
/* MOD_DATA hosts mod, so free it at last */
lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
+ dept_free_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
module_memory_free(mod, MOD_DATA);
}
@@ -3548,6 +3550,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
for_class_mod_mem_type(type, core_data) {
lockdep_free_key_range(mod->mem[type].base,
mod->mem[type].size);
+ dept_free_range(mod->mem[type].base,
+ mod->mem[type].size);
}
module_memory_restore_rox(mod);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b7801cd05d5a..d41112efaeae 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -69,6 +69,7 @@
#include <linux/wait_api.h>
#include <linux/workqueue_api.h>
#include <linux/livepatch_sched.h>
+#include <linux/dept.h>
#ifdef CONFIG_PREEMPT_DYNAMIC
# ifdef CONFIG_GENERIC_IRQ_ENTRY
@@ -4136,6 +4137,8 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
break;
+ dept_ttwu_stage_wait(p, _RET_IP_);
+
/*
* Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
* possible to, falsely, observe p->on_cpu == 0.
@@ -6737,6 +6740,11 @@ static void __sched notrace __schedule(int sched_mode)
rq = cpu_rq(cpu);
prev = rq->curr;
+ prev_state = READ_ONCE(prev->__state);
+ if (sched_mode != SM_PREEMPT && prev_state & TASK_NORMAL)
+ dept_request_event_wait_commit();
+
+ dept_sched_enter();
schedule_debug(prev, preempt);
if (sched_feat(HRTICK) || sched_feat(HRTICK_DL))
@@ -6871,6 +6879,7 @@ static void __sched notrace __schedule(int sched_mode)
raw_spin_rq_unlock_irq(rq);
}
trace_sched_exit_tp(is_switch);
+ dept_sched_exit();
}
void __noreturn do_task_dead(void)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 742b23ef0d8b..712514e2c149 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1368,6 +1368,32 @@ config DEBUG_PREEMPT
menu "Lock Debugging (spinlocks, mutexes, etc...)"
+config DEPT
+ bool "Dependency tracking (EXPERIMENTAL)"
+ depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
+ select DEBUG_SPINLOCK
+ select DEBUG_MUTEXES if !PREEMPT_RT
+ select DEBUG_RT_MUTEXES if RT_MUTEXES
+ select DEBUG_RWSEMS if !PREEMPT_RT
+ select DEBUG_WW_MUTEX_SLOWPATH
+ select DEBUG_LOCK_ALLOC
+ select TRACE_IRQFLAGS
+ select STACKTRACE
+ select KALLSYMS
+ select KALLSYMS_ALL
+ select PROVE_LOCKING
+ default n
+ help
+ Check dependencies between wait and event and report it if
+ deadlock possibility has been detected. Multiple reports are
+ allowed if there are more than a single problem.
+
+ This feature is considered EXPERIMENTAL that might produce
+ false positive reports because new dependencies start to be
+ tracked, that have never been tracked before. It's worth
+ noting, to mitigate the impact by the false positives, multi
+ reporting has been supported.
+
config LOCK_DEBUGGING_SUPPORT
bool
depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index d939403331b5..a7f8e59d0092 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -1398,6 +1398,8 @@ static void reset_locks(void)
local_irq_disable();
lockdep_free_key_range(&ww_lockdep.acquire_key, 1);
lockdep_free_key_range(&ww_lockdep.mutex_key, 1);
+ dept_free_range(&ww_lockdep.acquire_key, 1);
+ dept_free_range(&ww_lockdep.mutex_key, 1);
I1(A); I1(B); I1(C); I1(D);
I1(X1); I1(X2); I1(Y1); I1(Y2); I1(Z1); I1(Z2);
--
2.17.1
^ permalink raw reply related
* [PATCH v18 02/42] dept: add single event dependency tracker APIs
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
In-Reply-To: <20251205071855.72743-1-byungchul@sk.com>
Wrapped the base APIs for easier annotation on wait and event. Start
with supporting waiters on each single event. More general support for
multiple events is a future work. Do more when the need arises.
How to annotate:
1. Initaialize a map for the interesting wait.
/*
* Place along with the wait instance.
*/
struct dept_map my_wait;
/*
* Place in the initialization code.
*/
sdt_map_init(&my_wait);
2. Place the following at the wait code.
sdt_wait(&my_wait);
3. Place the following at the event code.
sdt_event(&my_wait);
That's it!
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/linux/dept_sdt.h | 65 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
create mode 100644 include/linux/dept_sdt.h
diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h
new file mode 100644
index 000000000000..0535f763b21b
--- /dev/null
+++ b/include/linux/dept_sdt.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Single-event Dependency Tracker
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ * Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ * Copyright (c) 2024 SK hynix, Inc., Byungchul Park
+ */
+
+#ifndef __LINUX_DEPT_SDT_H
+#define __LINUX_DEPT_SDT_H
+
+#include <linux/kernel.h>
+#include <linux/dept.h>
+
+#ifdef CONFIG_DEPT
+#define sdt_map_init(m) \
+ do { \
+ static struct dept_key __key; \
+ dept_map_init(m, &__key, 0, #m); \
+ } while (0)
+
+#define sdt_map_init_key(m, k) dept_map_init(m, k, 0, #m)
+
+#define sdt_wait(m) \
+ do { \
+ dept_request_event(m); \
+ dept_wait(m, 1UL, _THIS_IP_, __func__, 0); \
+ } while (0)
+
+/*
+ * sdt_might_sleep() and its family will be committed in __schedule()
+ * when it actually gets to __schedule(). Both dept_request_event() and
+ * dept_wait() will be performed on the commit.
+ */
+
+/*
+ * Use the code location as the class key if an explicit map is not used.
+ */
+#define sdt_might_sleep_start(m) \
+ do { \
+ struct dept_map *__m = m; \
+ static struct dept_key __key; \
+ dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__);\
+ } while (0)
+
+#define sdt_might_sleep_end() dept_clean_stage()
+
+#define sdt_ecxt_enter(m) dept_ecxt_enter(m, 1UL, _THIS_IP_, "start", "event", 0)
+#define sdt_event(m) dept_event(m, 1UL, _THIS_IP_, __func__)
+#define sdt_ecxt_exit(m) dept_ecxt_exit(m, 1UL, _THIS_IP_)
+#define sdt_request_event(m) dept_request_event(m)
+#else /* !CONFIG_DEPT */
+#define sdt_map_init(m) do { } while (0)
+#define sdt_map_init_key(m, k) do { (void)(k); } while (0)
+#define sdt_wait(m) do { } while (0)
+#define sdt_might_sleep_start(m) do { } while (0)
+#define sdt_might_sleep_end() do { } while (0)
+#define sdt_ecxt_enter(m) do { } while (0)
+#define sdt_event(m) do { } while (0)
+#define sdt_ecxt_exit(m) do { } while (0)
+#define sdt_request_event(m) do { } while (0)
+#endif
+#endif /* __LINUX_DEPT_SDT_H */
--
2.17.1
^ permalink raw reply related
* [PATCH v18 00/42] DEPT(DEPendency Tracker)
From: Byungchul Park @ 2025-12-05 7:18 UTC (permalink / raw)
To: linux-kernel
Cc: kernel_team, torvalds, damien.lemoal, linux-ide, adilger.kernel,
linux-ext4, mingo, peterz, will, tglx, rostedt, joel, sashal,
daniel.vetter, duyuyang, johannes.berg, tj, tytso, willy, david,
amir73il, gregkh, kernel-team, linux-mm, akpm, mhocko, minchan,
hannes, vdavydov.dev, sj, jglisse, dennis, cl, penberg, rientjes,
vbabka, ngupta, linux-block, josef, linux-fsdevel, jack, jlayton,
dan.j.williams, hch, djwong, dri-devel, rodrigosiqueiramelo,
melissa.srw, hamohammed.sa, harry.yoo, chris.p.wilson,
gwan-gyeong.mun, max.byungchul.park, boqun.feng, longman,
yunseong.kim, ysk, yeoreum.yun, netdev, matthew.brost, her0gyugyu,
corbet, catalin.marinas, bp, x86, hpa, luto, sumit.semwal,
gustavo, christian.koenig, andi.shyti, arnd, lorenzo.stoakes,
Liam.Howlett, rppt, surenb, mcgrof, petr.pavlu, da.gomez,
samitolvanen, paulmck, frederic, neeraj.upadhyay, joelagnelf,
josh, urezki, mathieu.desnoyers, jiangshanlai, qiang.zhang,
juri.lelli, vincent.guittot, dietmar.eggemann, bsegall, mgorman,
vschneid, chuck.lever, neil, okorniev, Dai.Ngo, tom, trondmy,
anna, kees, bigeasy, clrkwllms, mark.rutland, ada.coupriediaz,
kristina.martsenko, wangkefeng.wang, broonie, kevin.brodsky, dwmw,
shakeel.butt, ast, ziy, yuzhao, baolin.wang, usamaarif642,
joel.granados, richard.weiyang, geert+renesas, tim.c.chen, linux,
alexander.shishkin, lillian, chenhuacai, francesco,
guoweikang.kernel, link, jpoimboe, masahiroy, brauner,
thomas.weissschuh, oleg, mjguzik, andrii, wangfushuai, linux-doc,
linux-arm-kernel, linux-media, linaro-mm-sig, linux-i2c,
linux-arch, linux-modules, rcu, linux-nfs, linux-rt-devel,
2407018371, dakr, miguel.ojeda.sandonis, neilb, bagasdotme,
wsa+renesas, dave.hansen, geert, ojeda, alex.gaynor, gary,
bjorn3_gh, lossin, a.hindborg, aliceryhl, tmgross, rust-for-linux
I'm happy to see that DEPT reported real problems in practice:
https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@I-love.SAKURA.ne.jp/
https://lore.kernel.org/lkml/1674268856-31807-1-git-send-email-byungchul.park@lge.com/
https://lore.kernel.org/all/b6e00e77-4a8c-4e05-ab79-266bf05fcc2d@igalia.com/
I’ve added documentation describing DEPT — this should help you
understand what DEPT is and how it works. You can use DEPT simply by
enabling CONFIG_DEPT and checking dmesg at runtime.
---
Hi Linus and folks,
I’ve been developing a tool to detect deadlock possibilities by tracking
waits/events — rather than lock acquisition order — to cover all the
synchronization mechanisms. To summarize the design rationale, starting
from the problem statement, through analysis, to the solution:
CURRENT STATUS
--------------
Lockdep tracks lock acquisition order to identify deadlock conditions.
Additionally, it tracks IRQ state changes — via {en,dis}able — to
detect cases where locks are acquired unintentionally during
interrupt handling.
PROBLEM
-------
Waits and their associated events that are never reachable can
eventually lead to deadlocks. However, since Lockdep focuses solely
on lock acquisition order, it has inherent limitations when handling
waits and events.
Moreover, by tracking only lock acquisition order, Lockdep cannot
properly handle read locks or cross-event scenarios — such as
wait_for_completion() and complete() — making it increasingly
inadequate as a general-purpose deadlock detection tool.
SOLUTION
--------
Once again, waits and their associated events that are never
reachable can eventually lead to deadlocks. The new solution, DEPT,
focuses directly on waits and events. DEPT monitors waits and events,
and reports them when any become unreachable.
DEPT provides:
* Correct handling of read locks.
* Support for general waits and events.
* Continuous operation, even after multiple reports.
* Simple, intuitive annotation APIs.
There are still false positives, and some are already being worked on
for suppression. Especially splitting the folio class into several
appropriate classes e.g. block device mapping class and regular file
mapping class, is currently under active development by me and Yeoreum
Yun.
Anyway, these efforts will need to continue for a while, as we’ve seen
with lockdep over two decades. DEPT is tagged as EXPERIMENTAL in
Kconfig — meaning it’s not yet suitable for use as an automation tool.
However, for those who are interested in using DEPT to analyze complex
synchronization patterns and extract dependency insights, DEPT would be
a great tool for the purpose.
Thanks for your support and contributions to:
Harry Yoo <harry.yoo@oracle.com>
Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Yunseong Kim <ysk@kzalloc.com>
Yeoreum Yun <yeoreum.yun@arm.com>
FAQ
---
Q. Is this the first attempt to solve this problem?
A. No. The cross-release feature (commit b09be676e0ff2) attempted to
address it — as a Lockdep extension. It was merged, but quickly
reverted, because:
While it uncovered valuable hidden issues, it also introduced false
positives. Since these false positives mask further real problems
with Lockdep — and developers strongly dislike them — the feature was
rolled back.
Q. Why wasn’t DEPT built as a Lockdep extension?
A. Lockdep is the result of years of work by kernel developers — and is
now very stable. But I chose to build DEPT separately, because:
While reusing BFS(Breadth First Search) and Lockdep’s hashing is
beneficial, the rest of the system must be rebuilt from scratch to
align with DEPT’s wait-event model — since Lockdep was originally
designed for tracking lock acquisition orders, not wait-event
dependencies.
Q. Do you plan to replace Lockdep entirely?
A. Not at all — Lockdep still plays a vital role in validating correct
lock usage. While its dependency-checking logic should eventually be
superseded by DEPT, the rest of its functionality should stay.
Q. Should we replace the dependency check immediately?
A. Absolutely not. Lockdep’s stability is the result of years of hard
work by kernel developers. Lockdep and DEPT should run side by side
until DEPT matures.
Q. Stronger detection often leads to more false positives — which was a
major pain point when cross-release was added. Is DEPT designed to
handle this?
A. Yes. DEPT’s simple, generalized design enables flexible reporting —
so while false positives still need fixing, they’re far less
disruptive than they were under the Lockdep extension, cross-release.
Q. Why not fix all false positives out-of-tree before merging?
A. Since the affected subsystems span the entire kernel, like Lockdep,
which has relied on annotations to avoid false positives over the
last two decades, DEPT too will require the annotation efforts.
Performing annotation work within the mainline will help us add
annotations more appropriately and will also make DEPT a useful tool
for a wider range of users more quickly.
CONFIG_DEPT is marked EXPERIMENTAL, so it’s opt-in. Some users are
already interested in using DEPT to analyze complex synchronization
patterns and extract dependency insights.
Byungchul
---
Changes from v17:
1. Rebase on the mainline as of 2025 Dec 5.
2. Convert the documents' format from txt to rst. (feedbacked
by Jonathan Corbet and Bagas Sanjaya)
3. Move the documents from 'Documentation/dependency' to
'Documentation/dev-tools'. (feedbakced by Jonathan Corbet)
4. Improve the documentation. (feedbacked by NeilBrown)
5. Use a common function, enter_from_user_mode(), instead of
arch specific code, to notice context switch from user mode.
(feedbacked by Dave Hansen, Mark Rutland, and Mark Brown)
6. Resolve the header dependency issue by using dept's internal
header, instead of relocating 'struct llist_{head,node}' to
another header. (feedbacked by Greg KH)
7. Improve page(or folio) usage type APIs.
8. Add rust helper for wait_for_completion(). (feedbacked by
Guangbo Cui, Boqun Feng, and Danilo Krummrich)
9. Refine some commit messages.
Changes from v16:
1. Rebase on v6.17.
2. Fix a false positive from rcu (by Yunseong Kim)
3. Introduce APIs to set page's usage, dept_set_page_usage() and
dept_reset_page_usage() to avoid false positives.
4. Consider lock_page() as a potential wait unconditionally.
5. Consider folio_lock_killable() as a potential wait
unconditionally.
6. Add support for tracking PG_writeback waits and events.
7. Fix two build errors due to the additional debug information
added by dept. (by Yunseong Kim)
Changes from v15:
1. Fix typo and improve comments and commit messages (feedbacked
by ALOK TIWARI, Waiman Long, and kernel test robot).
2. Do not stop dept on detection of cicular dependency of
recover event, allowing to keep reporting.
3. Add SK hynix to copyright.
4. Consider folio_lock() as a potential wait unconditionally.
5. Fix Kconfig dependency bug (feedbacked by kernel test rebot).
6. Do not suppress reports that involve classes even that have
already involved in other reports, allowing to keep
reporting.
Changes from v14:
1. Rebase on the current latest, v6.15-rc6.
2. Refactor dept code.
3. With multi event sites for a single wait, even if an event
forms a circular dependency, the event can be recovered by
other event(or wake up) paths. Even though informing the
circular dependency is worthy but it should be suppressed
once informing it, if it doesn't lead an actual deadlock. So
introduce APIs to annotate the relationship between event
site and recover site, that are, event_site() and
dept_recover_event().
4. wait_for_completion() worked with dept map embedded in struct
completion. However, it generates a few false positves since
all the waits using the instance of struct completion, share
the map and key. To avoid the false positves, make it not to
share the map and key but each wait_for_completion() caller
have its own key by default. Of course, external maps also
can be used if needed.
5. Fix a bug about hardirq on/off tracing.
6. Implement basic unit test for dept.
7. Add more supports for dma fence synchronization.
8. Add emergency stop of dept e.g. on panic().
9. Fix false positives by mmu_notifier_invalidate_*().
10. Fix recursive call bug by DEPT_WARN_*() and DEPT_STOP().
11. Fix trivial bugs in DEPT_WARN_*() and DEPT_STOP().
12. Fix a bug that a spin lock, dept_pool_spin, is used in
both contexts of irq disabled and enabled without irq
disabled.
13. Suppress reports with classes, any of that already have
been reported, even though they have different chains but
being barely meaningful.
14. Print stacktrace of the wait that an event is now waking up,
not only stacktrace of the event.
15. Make dept aware of lockdep_cmp_fn() that is used to avoid
false positives in lockdep so that dept can also avoid them.
16. Do do_event() only if there are no ecxts have been
delimited.
17. Fix a bug that was not synchronized for stage_m in struct
dept_task, using a spin lock, dept_task()->stage_lock.
18. Fix a bug that dept didn't handle the case that multiple
ttwus for a single waiter can be called at the same time
e.i. a race issue.
19. Distinguish each kernel context from others, not only by
system call but also by user oriented fault so that dept can
work with more accuracy information about kernel context.
That helps to avoid a few false positives.
20. Limit dept's working to x86_64 and arm64.
Changes from v13:
1. Rebase on the current latest version, v6.9-rc7.
2. Add 'dept' documentation describing dept APIs.
Changes from v12:
1. Refine the whole document for dept.
2. Add 'Interpret dept report' section in the document, using a
deadlock report obtained in practice. Hope this version of
document helps guys understand dept better.
https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@I-love.SAKURA.ne.jp/#t
https://lore.kernel.org/lkml/1674268856-31807-1-git-send-email-byungchul.park@lge.com/
Changes from v11:
1. Add 'dept' documentation describing the concept of dept.
2. Rewrite the commit messages of the following commits for
using weaker lockdep annotation, for better description.
fs/jbd2: Use a weaker annotation in journal handling
cpu/hotplug: Use a weaker annotation in AP thread
(feedbacked by Thomas Gleixner)
Changes from v10:
1. Fix noinstr warning when building kernel source.
2. dept has been reporting some false positives due to the folio
lock's unfairness. Reflect it and make dept work based on
dept annotaions instead of just wait and wake up primitives.
3. Remove the support for PG_writeback while working on 2. I
will add the support later if needed.
4. dept didn't print stacktrace for [S] if the participant of a
deadlock is not lock mechanism but general wait and event.
However, it made hard to interpret the report in that case.
So add support to print stacktrace of the requestor who asked
the event context to run - usually a waiter of the event does
it just before going to wait state.
5. Give up tracking raw_local_irq_{disable,enable}() since it
totally messed up dept's irq tracking. So make it work in the
same way as lockdep does. I will consider it once any false
positives by those are observed again.
6. Change the manual rwsem_acquire_read(->j_trans_commit_map)
annotation in fs/jbd2/transaction.c to the try version so
that it works as much as it exactly needs.
7. Remove unnecessary 'inline' keyword in dept.c and add
'__maybe_unused' to a needed place.
Changes from v9:
1. Fix a bug. SDT tracking didn't work well because of my big
mistake that I should've used waiter's map to indentify its
class but it had been working with waker's one. FYI,
PG_locked and PG_writeback weren't affected. They still
worked well. (reported by YoungJun)
Changes from v8:
1. Fix build error by adding EXPORT_SYMBOL(PG_locked_map) and
EXPORT_SYMBOL(PG_writeback_map) for kernel module build -
appologize for that. (reported by kernel test robot)
2. Fix build error by removing header file's circular dependency
that was caused by "atomic.h", "kernel.h" and "irqflags.h",
which I introduced - appolgize for that. (reported by kernel
test robot)
Changes from v7:
1. Fix a bug that cannot track rwlock dependency properly,
introduced in v7. (reported by Boqun and lockdep selftest)
2. Track wait/event of PG_{locked,writeback} more aggressively
assuming that when a bit of PG_{locked,writeback} is cleared
there might be waits on the bit. (reported by Linus, Hillf
and syzbot)
3. Fix and clean bad style code e.i. unnecessarily introduced
a randome pattern and so on. (pointed out by Linux)
4. Clean code for applying dept to wait_for_completion().
Changes from v6:
1. Tie to task scheduler code to track sleep and try_to_wake_up()
assuming sleeps cause waits, try_to_wake_up()s would be the
events that those are waiting for, of course with proper dept
annotations, sdt_might_sleep_weak(), sdt_might_sleep_strong()
and so on. For these cases, class is classified at sleep
entrance rather than the synchronization initialization code.
Which would extremely reduce false alarms.
2. Remove the dept associated instance in each page struct for
tracking dependencies by PG_locked and PG_writeback thanks to
the 1. work above.
3. Introduce CONFIG_dept_AGGRESIVE_TIMEOUT_WAIT to suppress
reports that waits with timeout set are involved, for those
who don't like verbose reporting.
4. Add a mechanism to refill the internal memory pools on
running out so that dept could keep working as long as free
memory is available in the system.
5. Re-enable tracking hashed-waitqueue wait. That's going to no
longer generate false positives because class is classified
at sleep entrance rather than the waitqueue initailization.
6. Refactor to make it easier to port onto each new version of
the kernel.
7. Apply dept to dma fence.
8. Do trivial optimizaitions.
Changes from v5:
1. Use just pr_warn_once() rather than WARN_ONCE() on the lack
of internal resources because WARN_*() printing stacktrace is
too much for informing the lack. (feedback from Ted, Hyeonggon)
2. Fix trivial bugs like missing initializing a struct before
using it.
3. Assign a different class per task when handling onstack
variables for waitqueue or the like. Which makes dept
distinguish between onstack variables of different tasks so
as to prevent false positives. (reported by Hyeonggon)
4. Make dept aware of even raw_local_irq_*() to prevent false
positives. (reported by Hyeonggon)
5. Don't consider dependencies between the events that might be
triggered within __schedule() and the waits that requires
__schedule(), real ones. (reported by Hyeonggon)
6. Unstage the staged wait that has prepare_to_wait_event()'ed
*and* yet to get to __schedule(), if we encounter __schedule()
in-between for another sleep, which is possible if e.g. a
mutex_lock() exists in 'condition' of ___wait_event().
7. Turn on CONFIG_PROVE_LOCKING when CONFIG_DEPT is on, to rely
on the hardirq and softirq entrance tracing to make dept more
portable for now.
Changes from v4:
1. Fix some bugs that produce false alarms.
2. Distinguish each syscall context from another *for arm64*.
3. Make it not warn it but just print it in case dept ring
buffer gets exhausted. (feedback from Hyeonggon)
4. Explicitely describe "EXPERIMENTAL" and "dept might produce
false positive reports" in Kconfig. (feedback from Ted)
Changes from v3:
1. dept shouldn't create dependencies between different depths
of a class that were indicated by *_lock_nested(). dept
normally doesn't but it does once another lock class comes
in. So fixed it. (feedback from Hyeonggon)
2. dept considered a wait as a real wait once getting to
__schedule() even if it has been set to TASK_RUNNING by wake
up sources in advance. Fixed it so that dept doesn't consider
the case as a real wait. (feedback from Jan Kara)
3. Stop tracking dependencies with a map once the event
associated with the map has been handled. dept will start to
work with the map again, on the next sleep.
Changes from v2:
1. Disable dept on bit_wait_table[] in sched/wait_bit.c
reporting a lot of false positives, which is my fault.
Wait/event for bit_wait_table[] should've been tagged in a
higher layer for better work, which is a future work.
(feedback from Jan Kara)
2. Disable dept on crypto_larval's completion to prevent a false
positive.
Changes from v1:
1. Fix coding style and typo. (feedback from Steven)
2. Distinguish each work context from another in workqueue.
3. Skip checking lock acquisition with nest_lock, which is about
correct lock usage that should be checked by lockdep.
Changes from RFC(v0):
1. Prevent adding a wait tag at prepare_to_wait() but __schedule().
(feedback from Linus and Matthew)
2. Use try version at lockdep_acquire_cpus_lock() annotation.
3. Distinguish each syscall context from another.
Byungchul Park (41):
dept: implement DEPT(DEPendency Tracker)
dept: add single event dependency tracker APIs
dept: add lock dependency tracker APIs
dept: tie to lockdep and IRQ tracing
dept: add proc knobs to show stats and dependency graph
dept: distinguish each kernel context from another
dept: distinguish each work from another
dept: add a mechanism to refill the internal memory pools on running
out
dept: record the latest one out of consecutive waits of the same class
dept: apply sdt_might_sleep_{start,end}() to
wait_for_completion()/complete()
dept: apply sdt_might_sleep_{start,end}() to swait
dept: apply sdt_might_sleep_{start,end}() to waitqueue wait
dept: apply sdt_might_sleep_{start,end}() to hashed-waitqueue wait
dept: apply sdt_might_sleep_{start,end}() to dma fence
dept: track timeout waits separately with a new Kconfig
dept: apply timeout consideration to wait_for_completion()/complete()
dept: apply timeout consideration to swait
dept: apply timeout consideration to waitqueue wait
dept: apply timeout consideration to hashed-waitqueue wait
dept: apply timeout consideration to dma fence wait
dept: make dept able to work with an external wgen
dept: track PG_locked with dept
dept: print staged wait's stacktrace on report
locking/lockdep: prevent various lockdep assertions when
lockdep_off()'ed
dept: add documents for dept
cpu/hotplug: use a weaker annotation in AP thread
dept: assign dept map to mmu notifier invalidation synchronization
dept: assign unique dept_key to each distinct dma fence caller
dept: make dept aware of lockdep_set_lock_cmp_fn() annotation
dept: make dept stop from working on debug_locks_off()
dept: assign unique dept_key to each distinct wait_for_completion()
caller
completion, dept: introduce init_completion_dmap() API
dept: introduce a new type of dependency tracking between multi event
sites
dept: add module support for struct dept_event_site and
dept_event_site_dep
dept: introduce event_site() to disable event tracking if it's
recoverable
dept: implement a basic unit test for dept
dept: call dept_hardirqs_off() in local_irq_*() regardless of irq
state
dept: introduce APIs to set page usage and use subclasses_evt for the
usage
dept: track PG_writeback with dept
SUNRPC: relocate struct rcu_head to the first field of struct rpc_xprt
mm: percpu: increase PERCPU_DYNAMIC_SIZE_SHIFT on DEPT and large
PAGE_SIZE
Yunseong Kim (1):
rcu/update: fix same dept key collision between various types of RCU
Documentation/dev-tools/dept.rst | 778 ++++++
Documentation/dev-tools/dept_api.rst | 125 +
drivers/dma-buf/dma-fence.c | 23 +-
include/asm-generic/vmlinux.lds.h | 13 +-
include/linux/completion.h | 124 +-
include/linux/dept.h | 402 +++
include/linux/dept_ldt.h | 78 +
include/linux/dept_sdt.h | 68 +
include/linux/dept_unit_test.h | 67 +
include/linux/dma-fence.h | 74 +-
include/linux/hardirq.h | 3 +
include/linux/irq-entry-common.h | 4 +
include/linux/irqflags.h | 21 +-
include/linux/local_lock_internal.h | 1 +
include/linux/lockdep.h | 105 +-
include/linux/lockdep_types.h | 3 +
include/linux/mm_types.h | 4 +
include/linux/mmu_notifier.h | 26 +
include/linux/module.h | 5 +
include/linux/mutex.h | 1 +
include/linux/page-flags.h | 217 +-
include/linux/pagemap.h | 37 +-
include/linux/percpu-rwsem.h | 2 +-
include/linux/percpu.h | 4 +
include/linux/rcupdate_wait.h | 13 +-
include/linux/rtmutex.h | 1 +
include/linux/rwlock_types.h | 1 +
include/linux/rwsem.h | 1 +
include/linux/sched.h | 118 +
include/linux/seqlock.h | 2 +-
include/linux/spinlock_types_raw.h | 3 +
include/linux/srcu.h | 2 +-
include/linux/sunrpc/xprt.h | 9 +-
include/linux/swait.h | 3 +
include/linux/wait.h | 3 +
include/linux/wait_bit.h | 3 +
init/init_task.c | 2 +
init/main.c | 2 +
kernel/Makefile | 1 +
kernel/cpu.c | 2 +-
kernel/dependency/Makefile | 5 +
kernel/dependency/dept.c | 3499 ++++++++++++++++++++++++++
kernel/dependency/dept_hash.h | 10 +
kernel/dependency/dept_internal.h | 314 +++
kernel/dependency/dept_object.h | 13 +
kernel/dependency/dept_proc.c | 94 +
kernel/dependency/dept_unit_test.c | 173 ++
kernel/exit.c | 1 +
kernel/fork.c | 2 +
kernel/locking/lockdep.c | 33 +
kernel/module/main.c | 19 +
kernel/rcu/rcu.h | 1 +
kernel/rcu/update.c | 5 +-
kernel/sched/completion.c | 62 +-
kernel/sched/core.c | 9 +
kernel/workqueue.c | 3 +
lib/Kconfig.debug | 48 +
lib/debug_locks.c | 2 +
lib/locking-selftest.c | 2 +
mm/filemap.c | 38 +
mm/mm_init.c | 3 +
mm/mmu_notifier.c | 31 +-
rust/helpers/completion.c | 5 +
63 files changed, 6602 insertions(+), 121 deletions(-)
create mode 100644 Documentation/dev-tools/dept.rst
create mode 100644 Documentation/dev-tools/dept_api.rst
create mode 100644 include/linux/dept.h
create mode 100644 include/linux/dept_ldt.h
create mode 100644 include/linux/dept_sdt.h
create mode 100644 include/linux/dept_unit_test.h
create mode 100644 kernel/dependency/Makefile
create mode 100644 kernel/dependency/dept.c
create mode 100644 kernel/dependency/dept_hash.h
create mode 100644 kernel/dependency/dept_internal.h
create mode 100644 kernel/dependency/dept_object.h
create mode 100644 kernel/dependency/dept_proc.c
create mode 100644 kernel/dependency/dept_unit_test.c
base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0
--
2.17.1
^ permalink raw reply
* Re: [PATCH V2] mm/slab: introduce kvfree_rcu_barrier_on_cache() for cache destruction
From: Harry Yoo @ 2025-12-05 1:13 UTC (permalink / raw)
To: Suren Baghdasaryan
Cc: vbabka, Liam.Howlett, cl, rientjes, roman.gushchin, urezki,
sidhartha.kumar, linux-mm, linux-kernel, rcu, maple-tree,
linux-modules, mcgrof, petr.pavlu, samitolvanen, atomlin,
lucas.demarchi, akpm, jonathanh, stable, Daniel Gomez
In-Reply-To: <CAJuCfpE+g65Dm8-r=psDJQf_O1rfBG62DOzx4mE1mb+ottUKmQ@mail.gmail.com>
On Thu, Dec 04, 2025 at 02:05:07PM -0800, Suren Baghdasaryan wrote:
> On Tue, Dec 2, 2025 at 2:16 AM Harry Yoo <harry.yoo@oracle.com> wrote:
> >
> > Currently, kvfree_rcu_barrier() flushes RCU sheaves across all slab
> > caches when a cache is destroyed. This is unnecessary; only the RCU
> > sheaves belonging to the cache being destroyed need to be flushed.
> >
> > As suggested by Vlastimil Babka, introduce a weaker form of
> > kvfree_rcu_barrier() that operates on a specific slab cache.
> >
> > Factor out flush_rcu_sheaves_on_cache() from flush_all_rcu_sheaves() and
> > call it from flush_all_rcu_sheaves() and kvfree_rcu_barrier_on_cache().
> >
> > Call kvfree_rcu_barrier_on_cache() instead of kvfree_rcu_barrier() on
> > cache destruction.
> >
> > The performance benefit is evaluated on a 12 core 24 threads AMD Ryzen
> > 5900X machine (1 socket), by loading slub_kunit module.
> >
> > Before:
> > Total calls: 19
> > Average latency (us): 18127
> > Total time (us): 344414
> >
> > After:
> > Total calls: 19
> > Average latency (us): 10066
> > Total time (us): 191264
> >
> > Two performance regression have been reported:
> > - stress module loader test's runtime increases by 50-60% (Daniel)
> > - internal graphics test's runtime on Tegra23 increases by 35% (Jon)
> >
> > They are fixed by this change.
> >
> > Suggested-by: Vlastimil Babka <vbabka@suse.cz>
> > Fixes: ec66e0d59952 ("slab: add sheaf support for batching kfree_rcu() operations")
> > Cc: <stable@vger.kernel.org>
> > Link: https://lore.kernel.org/linux-mm/1bda09da-93be-4737-aef0-d47f8c5c9301@suse.cz
> > Reported-and-tested-by: Daniel Gomez <da.gomez@samsung.com>
> > Closes: https://lore.kernel.org/linux-mm/0406562e-2066-4cf8-9902-b2b0616dd742@kernel.org
> > Reported-and-tested-by: Jon Hunter <jonathanh@nvidia.com>
> > Closes: https://lore.kernel.org/linux-mm/e988eff6-1287-425e-a06c-805af5bbf262@nvidia.com
> > Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> > ---
> >
> > No code change, added proper tags and updated changelog.
> >
> > include/linux/slab.h | 5 ++++
> > mm/slab.h | 1 +
> > mm/slab_common.c | 52 +++++++++++++++++++++++++++++------------
> > mm/slub.c | 55 ++++++++++++++++++++++++--------------------
> > 4 files changed, 73 insertions(+), 40 deletions(-)
> >
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index cf443f064a66..937c93d44e8c 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -1149,6 +1149,10 @@ static inline void kvfree_rcu_barrier(void)
> > {
> > rcu_barrier();
> > }
> > +static inline void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
> > +{
> > + rcu_barrier();
> > +}
> >
> > static inline void kfree_rcu_scheduler_running(void) { }
> > #else
> > @@ -1156,6 +1160,7 @@ void kvfree_rcu_barrier(void);
> >
> > void kfree_rcu_scheduler_running(void);
> > #endif
> > +void kvfree_rcu_barrier_on_cache(struct kmem_cache *s);
>
> Should the above line be before the #endif? I was expecting something like this:
>
> #ifndef CONFIG_KVFREE_RCU_BATCHED
> ...
> static inline void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
> {
> rcu_barrier();
> }
> #else
> ...
> void kvfree_rcu_barrier_on_cache(struct kmem_cache *s);
> #endif
>
> but when I apply this patch on mm-new I get this:
>
> #ifndef CONFIG_KVFREE_RCU_BATCHED
> ...
> static inline void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
> {
> rcu_barrier();
> }
> #else
> ...
> #endif
> void kvfree_rcu_barrier_on_cache(struct kmem_cache *s);
Oops, nice catch!
Interestingly this didn't break CONFIG_KVFREE_RCU_BATCHED=n builds...
I'll send V3 shortly.
> Other than that LGTM
Thanks!
> > /**
> > * kmalloc_size_roundup - Report allocation bucket size for the given size
> > diff --git a/mm/slab.h b/mm/slab.h
> > index f730e012553c..e767aa7e91b0 100644
> > --- a/mm/slab.h
> > +++ b/mm/slab.h
> > @@ -422,6 +422,7 @@ static inline bool is_kmalloc_normal(struct kmem_cache *s)
> >
> > bool __kfree_rcu_sheaf(struct kmem_cache *s, void *obj);
> > void flush_all_rcu_sheaves(void);
> > +void flush_rcu_sheaves_on_cache(struct kmem_cache *s);
> >
> > #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
> > SLAB_CACHE_DMA32 | SLAB_PANIC | \
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > index 84dfff4f7b1f..dd8a49d6f9cc 100644
> > --- a/mm/slab_common.c
> > +++ b/mm/slab_common.c
> > @@ -492,7 +492,7 @@ void kmem_cache_destroy(struct kmem_cache *s)
> > return;
> >
> > /* in-flight kfree_rcu()'s may include objects from our cache */
> > - kvfree_rcu_barrier();
> > + kvfree_rcu_barrier_on_cache(s);
> >
> > if (IS_ENABLED(CONFIG_SLUB_RCU_DEBUG) &&
> > (s->flags & SLAB_TYPESAFE_BY_RCU)) {
> > @@ -2038,25 +2038,13 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
> > }
> > EXPORT_SYMBOL_GPL(kvfree_call_rcu);
> >
> > -/**
> > - * kvfree_rcu_barrier - Wait until all in-flight kvfree_rcu() complete.
> > - *
> > - * Note that a single argument of kvfree_rcu() call has a slow path that
> > - * triggers synchronize_rcu() following by freeing a pointer. It is done
> > - * before the return from the function. Therefore for any single-argument
> > - * call that will result in a kfree() to a cache that is to be destroyed
> > - * during module exit, it is developer's responsibility to ensure that all
> > - * such calls have returned before the call to kmem_cache_destroy().
> > - */
> > -void kvfree_rcu_barrier(void)
> > +static inline void __kvfree_rcu_barrier(void)
> > {
> > struct kfree_rcu_cpu_work *krwp;
> > struct kfree_rcu_cpu *krcp;
> > bool queued;
> > int i, cpu;
> >
> > - flush_all_rcu_sheaves();
> > -
> > /*
> > * Firstly we detach objects and queue them over an RCU-batch
> > * for all CPUs. Finally queued works are flushed for each CPU.
> > @@ -2118,8 +2106,43 @@ void kvfree_rcu_barrier(void)
> > }
> > }
> > }
> > +
> > +/**
> > + * kvfree_rcu_barrier - Wait until all in-flight kvfree_rcu() complete.
> > + *
> > + * Note that a single argument of kvfree_rcu() call has a slow path that
> > + * triggers synchronize_rcu() following by freeing a pointer. It is done
> > + * before the return from the function. Therefore for any single-argument
> > + * call that will result in a kfree() to a cache that is to be destroyed
> > + * during module exit, it is developer's responsibility to ensure that all
> > + * such calls have returned before the call to kmem_cache_destroy().
> > + */
> > +void kvfree_rcu_barrier(void)
> > +{
> > + flush_all_rcu_sheaves();
> > + __kvfree_rcu_barrier();
> > +}
> > EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
> >
> > +/**
> > + * kvfree_rcu_barrier_on_cache - Wait for in-flight kvfree_rcu() calls on a
> > + * specific slab cache.
> > + * @s: slab cache to wait for
> > + *
> > + * See the description of kvfree_rcu_barrier() for details.
> > + */
> > +void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
> > +{
> > + if (s->cpu_sheaves)
> > + flush_rcu_sheaves_on_cache(s);
> > + /*
> > + * TODO: Introduce a version of __kvfree_rcu_barrier() that works
> > + * on a specific slab cache.
> > + */
> > + __kvfree_rcu_barrier();
> > +}
> > +EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
> > +
> > static unsigned long
> > kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> > {
> > @@ -2215,4 +2238,3 @@ void __init kvfree_rcu_init(void)
> > }
> >
> > #endif /* CONFIG_KVFREE_RCU_BATCHED */
> > -
> > diff --git a/mm/slub.c b/mm/slub.c
> > index 785e25a14999..7cec2220712b 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -4118,42 +4118,47 @@ static void flush_rcu_sheaf(struct work_struct *w)
> >
> >
> > /* needed for kvfree_rcu_barrier() */
> > -void flush_all_rcu_sheaves(void)
> > +void flush_rcu_sheaves_on_cache(struct kmem_cache *s)
> > {
> > struct slub_flush_work *sfw;
> > - struct kmem_cache *s;
> > unsigned int cpu;
> >
> > - cpus_read_lock();
> > - mutex_lock(&slab_mutex);
> > + mutex_lock(&flush_lock);
> >
> > - list_for_each_entry(s, &slab_caches, list) {
> > - if (!s->cpu_sheaves)
> > - continue;
> > + for_each_online_cpu(cpu) {
> > + sfw = &per_cpu(slub_flush, cpu);
> >
> > - mutex_lock(&flush_lock);
> > + /*
> > + * we don't check if rcu_free sheaf exists - racing
> > + * __kfree_rcu_sheaf() might have just removed it.
> > + * by executing flush_rcu_sheaf() on the cpu we make
> > + * sure the __kfree_rcu_sheaf() finished its call_rcu()
> > + */
> >
> > - for_each_online_cpu(cpu) {
> > - sfw = &per_cpu(slub_flush, cpu);
> > + INIT_WORK(&sfw->work, flush_rcu_sheaf);
> > + sfw->s = s;
> > + queue_work_on(cpu, flushwq, &sfw->work);
> > + }
> >
> > - /*
> > - * we don't check if rcu_free sheaf exists - racing
> > - * __kfree_rcu_sheaf() might have just removed it.
> > - * by executing flush_rcu_sheaf() on the cpu we make
> > - * sure the __kfree_rcu_sheaf() finished its call_rcu()
> > - */
> > + for_each_online_cpu(cpu) {
> > + sfw = &per_cpu(slub_flush, cpu);
> > + flush_work(&sfw->work);
> > + }
> >
> > - INIT_WORK(&sfw->work, flush_rcu_sheaf);
> > - sfw->s = s;
> > - queue_work_on(cpu, flushwq, &sfw->work);
> > - }
> > + mutex_unlock(&flush_lock);
> > +}
> >
> > - for_each_online_cpu(cpu) {
> > - sfw = &per_cpu(slub_flush, cpu);
> > - flush_work(&sfw->work);
> > - }
> > +void flush_all_rcu_sheaves(void)
> > +{
> > + struct kmem_cache *s;
> > +
> > + cpus_read_lock();
> > + mutex_lock(&slab_mutex);
> >
> > - mutex_unlock(&flush_lock);
> > + list_for_each_entry(s, &slab_caches, list) {
> > + if (!s->cpu_sheaves)
> > + continue;
> > + flush_rcu_sheaves_on_cache(s);
> > }
> >
> > mutex_unlock(&slab_mutex);
> > --
> > 2.43.0
> >
--
Cheers,
Harry / Hyeonggon
^ permalink raw reply
* Re: [PATCH V2] mm/slab: introduce kvfree_rcu_barrier_on_cache() for cache destruction
From: Suren Baghdasaryan @ 2025-12-04 22:05 UTC (permalink / raw)
To: Harry Yoo
Cc: vbabka, Liam.Howlett, cl, rientjes, roman.gushchin, urezki,
sidhartha.kumar, linux-mm, linux-kernel, rcu, maple-tree,
linux-modules, mcgrof, petr.pavlu, samitolvanen, atomlin,
lucas.demarchi, akpm, jonathanh, stable, Daniel Gomez
In-Reply-To: <20251202101626.783736-1-harry.yoo@oracle.com>
On Tue, Dec 2, 2025 at 2:16 AM Harry Yoo <harry.yoo@oracle.com> wrote:
>
> Currently, kvfree_rcu_barrier() flushes RCU sheaves across all slab
> caches when a cache is destroyed. This is unnecessary; only the RCU
> sheaves belonging to the cache being destroyed need to be flushed.
>
> As suggested by Vlastimil Babka, introduce a weaker form of
> kvfree_rcu_barrier() that operates on a specific slab cache.
>
> Factor out flush_rcu_sheaves_on_cache() from flush_all_rcu_sheaves() and
> call it from flush_all_rcu_sheaves() and kvfree_rcu_barrier_on_cache().
>
> Call kvfree_rcu_barrier_on_cache() instead of kvfree_rcu_barrier() on
> cache destruction.
>
> The performance benefit is evaluated on a 12 core 24 threads AMD Ryzen
> 5900X machine (1 socket), by loading slub_kunit module.
>
> Before:
> Total calls: 19
> Average latency (us): 18127
> Total time (us): 344414
>
> After:
> Total calls: 19
> Average latency (us): 10066
> Total time (us): 191264
>
> Two performance regression have been reported:
> - stress module loader test's runtime increases by 50-60% (Daniel)
> - internal graphics test's runtime on Tegra23 increases by 35% (Jon)
>
> They are fixed by this change.
>
> Suggested-by: Vlastimil Babka <vbabka@suse.cz>
> Fixes: ec66e0d59952 ("slab: add sheaf support for batching kfree_rcu() operations")
> Cc: <stable@vger.kernel.org>
> Link: https://lore.kernel.org/linux-mm/1bda09da-93be-4737-aef0-d47f8c5c9301@suse.cz
> Reported-and-tested-by: Daniel Gomez <da.gomez@samsung.com>
> Closes: https://lore.kernel.org/linux-mm/0406562e-2066-4cf8-9902-b2b0616dd742@kernel.org
> Reported-and-tested-by: Jon Hunter <jonathanh@nvidia.com>
> Closes: https://lore.kernel.org/linux-mm/e988eff6-1287-425e-a06c-805af5bbf262@nvidia.com
> Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> ---
>
> No code change, added proper tags and updated changelog.
>
> include/linux/slab.h | 5 ++++
> mm/slab.h | 1 +
> mm/slab_common.c | 52 +++++++++++++++++++++++++++++------------
> mm/slub.c | 55 ++++++++++++++++++++++++--------------------
> 4 files changed, 73 insertions(+), 40 deletions(-)
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index cf443f064a66..937c93d44e8c 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -1149,6 +1149,10 @@ static inline void kvfree_rcu_barrier(void)
> {
> rcu_barrier();
> }
> +static inline void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
> +{
> + rcu_barrier();
> +}
>
> static inline void kfree_rcu_scheduler_running(void) { }
> #else
> @@ -1156,6 +1160,7 @@ void kvfree_rcu_barrier(void);
>
> void kfree_rcu_scheduler_running(void);
> #endif
> +void kvfree_rcu_barrier_on_cache(struct kmem_cache *s);
Should the above line be before the #endif? I was expecting something like this:
#ifndef CONFIG_KVFREE_RCU_BATCHED
...
static inline void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
{
rcu_barrier();
}
#else
...
void kvfree_rcu_barrier_on_cache(struct kmem_cache *s);
#endif
but when I apply this patch on mm-new I get this:
#ifndef CONFIG_KVFREE_RCU_BATCHED
...
static inline void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
{
rcu_barrier();
}
#else
...
#endif
void kvfree_rcu_barrier_on_cache(struct kmem_cache *s);
Other than that LGTM
>
> /**
> * kmalloc_size_roundup - Report allocation bucket size for the given size
> diff --git a/mm/slab.h b/mm/slab.h
> index f730e012553c..e767aa7e91b0 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -422,6 +422,7 @@ static inline bool is_kmalloc_normal(struct kmem_cache *s)
>
> bool __kfree_rcu_sheaf(struct kmem_cache *s, void *obj);
> void flush_all_rcu_sheaves(void);
> +void flush_rcu_sheaves_on_cache(struct kmem_cache *s);
>
> #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
> SLAB_CACHE_DMA32 | SLAB_PANIC | \
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 84dfff4f7b1f..dd8a49d6f9cc 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -492,7 +492,7 @@ void kmem_cache_destroy(struct kmem_cache *s)
> return;
>
> /* in-flight kfree_rcu()'s may include objects from our cache */
> - kvfree_rcu_barrier();
> + kvfree_rcu_barrier_on_cache(s);
>
> if (IS_ENABLED(CONFIG_SLUB_RCU_DEBUG) &&
> (s->flags & SLAB_TYPESAFE_BY_RCU)) {
> @@ -2038,25 +2038,13 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
> }
> EXPORT_SYMBOL_GPL(kvfree_call_rcu);
>
> -/**
> - * kvfree_rcu_barrier - Wait until all in-flight kvfree_rcu() complete.
> - *
> - * Note that a single argument of kvfree_rcu() call has a slow path that
> - * triggers synchronize_rcu() following by freeing a pointer. It is done
> - * before the return from the function. Therefore for any single-argument
> - * call that will result in a kfree() to a cache that is to be destroyed
> - * during module exit, it is developer's responsibility to ensure that all
> - * such calls have returned before the call to kmem_cache_destroy().
> - */
> -void kvfree_rcu_barrier(void)
> +static inline void __kvfree_rcu_barrier(void)
> {
> struct kfree_rcu_cpu_work *krwp;
> struct kfree_rcu_cpu *krcp;
> bool queued;
> int i, cpu;
>
> - flush_all_rcu_sheaves();
> -
> /*
> * Firstly we detach objects and queue them over an RCU-batch
> * for all CPUs. Finally queued works are flushed for each CPU.
> @@ -2118,8 +2106,43 @@ void kvfree_rcu_barrier(void)
> }
> }
> }
> +
> +/**
> + * kvfree_rcu_barrier - Wait until all in-flight kvfree_rcu() complete.
> + *
> + * Note that a single argument of kvfree_rcu() call has a slow path that
> + * triggers synchronize_rcu() following by freeing a pointer. It is done
> + * before the return from the function. Therefore for any single-argument
> + * call that will result in a kfree() to a cache that is to be destroyed
> + * during module exit, it is developer's responsibility to ensure that all
> + * such calls have returned before the call to kmem_cache_destroy().
> + */
> +void kvfree_rcu_barrier(void)
> +{
> + flush_all_rcu_sheaves();
> + __kvfree_rcu_barrier();
> +}
> EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>
> +/**
> + * kvfree_rcu_barrier_on_cache - Wait for in-flight kvfree_rcu() calls on a
> + * specific slab cache.
> + * @s: slab cache to wait for
> + *
> + * See the description of kvfree_rcu_barrier() for details.
> + */
> +void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
> +{
> + if (s->cpu_sheaves)
> + flush_rcu_sheaves_on_cache(s);
> + /*
> + * TODO: Introduce a version of __kvfree_rcu_barrier() that works
> + * on a specific slab cache.
> + */
> + __kvfree_rcu_barrier();
> +}
> +EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
> +
> static unsigned long
> kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> {
> @@ -2215,4 +2238,3 @@ void __init kvfree_rcu_init(void)
> }
>
> #endif /* CONFIG_KVFREE_RCU_BATCHED */
> -
> diff --git a/mm/slub.c b/mm/slub.c
> index 785e25a14999..7cec2220712b 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4118,42 +4118,47 @@ static void flush_rcu_sheaf(struct work_struct *w)
>
>
> /* needed for kvfree_rcu_barrier() */
> -void flush_all_rcu_sheaves(void)
> +void flush_rcu_sheaves_on_cache(struct kmem_cache *s)
> {
> struct slub_flush_work *sfw;
> - struct kmem_cache *s;
> unsigned int cpu;
>
> - cpus_read_lock();
> - mutex_lock(&slab_mutex);
> + mutex_lock(&flush_lock);
>
> - list_for_each_entry(s, &slab_caches, list) {
> - if (!s->cpu_sheaves)
> - continue;
> + for_each_online_cpu(cpu) {
> + sfw = &per_cpu(slub_flush, cpu);
>
> - mutex_lock(&flush_lock);
> + /*
> + * we don't check if rcu_free sheaf exists - racing
> + * __kfree_rcu_sheaf() might have just removed it.
> + * by executing flush_rcu_sheaf() on the cpu we make
> + * sure the __kfree_rcu_sheaf() finished its call_rcu()
> + */
>
> - for_each_online_cpu(cpu) {
> - sfw = &per_cpu(slub_flush, cpu);
> + INIT_WORK(&sfw->work, flush_rcu_sheaf);
> + sfw->s = s;
> + queue_work_on(cpu, flushwq, &sfw->work);
> + }
>
> - /*
> - * we don't check if rcu_free sheaf exists - racing
> - * __kfree_rcu_sheaf() might have just removed it.
> - * by executing flush_rcu_sheaf() on the cpu we make
> - * sure the __kfree_rcu_sheaf() finished its call_rcu()
> - */
> + for_each_online_cpu(cpu) {
> + sfw = &per_cpu(slub_flush, cpu);
> + flush_work(&sfw->work);
> + }
>
> - INIT_WORK(&sfw->work, flush_rcu_sheaf);
> - sfw->s = s;
> - queue_work_on(cpu, flushwq, &sfw->work);
> - }
> + mutex_unlock(&flush_lock);
> +}
>
> - for_each_online_cpu(cpu) {
> - sfw = &per_cpu(slub_flush, cpu);
> - flush_work(&sfw->work);
> - }
> +void flush_all_rcu_sheaves(void)
> +{
> + struct kmem_cache *s;
> +
> + cpus_read_lock();
> + mutex_lock(&slab_mutex);
>
> - mutex_unlock(&flush_lock);
> + list_for_each_entry(s, &slab_caches, list) {
> + if (!s->cpu_sheaves)
> + continue;
> + flush_rcu_sheaves_on_cache(s);
> }
>
> mutex_unlock(&slab_mutex);
> --
> 2.43.0
>
^ permalink raw reply
* Re: [GIT PULL] Modules changes for v6.19-rc1
From: Daniel Gomez @ 2025-12-04 11:52 UTC (permalink / raw)
To: Linus Torvalds
Cc: Luis Chamberlain, Petr Pavlu, Sami Tolvanen, Daniel Gomez,
Mauro Carvalho Chehab, Hans Verkuil, Andreas Hindborg,
Uwe Kleine-König, Aaron Tomlin, Kees Cook, linux-modules,
linux-kernel
In-Reply-To: <20251203234840.3720-1-da.gomez@kernel.org>
On 04/12/2025 00.48, Daniel Gomez wrote:
> The following changes since commit dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa:
>
> Linux 6.18-rc3 (2025-10-26 15:59:49 -0700)
>
> are available in the Git repository at:
>
> ssh://git@gitolite.kernel.org/pub/scm/linux/kernel/git/modules/linux.git/ tags/modules-6.19-rc1
I know the preference is to use git:// but my git config resolved to the above
link. Here what I intended to do:
git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux.git tags/modules-6.19-rc1
> The changes have been in linux-next for 4 weeks. Recent 0day reports for UM [3]
> and arm64 [4] builds were not reproducible and traced to a buggy bindgen version
> combined with unreleased clang-22 in 0day. The Rust team has reported this to
> 0day.
FYI, this has been confirmed by 0day:
https://lore.kernel.org/all/aTEi3KUUkPVGS3ix@xsang-OptiPlex-9020/
> @@@ -329,25 -179,30 +332,30 @@@ pub(crate) fn module(ts: TokenStream) -
> // Rust does not allow hyphens in identifiers, use underscore instead.
> let ident = info.name.replace('-', "_");
> let mut modinfo = ModInfoBuilder::new(ident.as_ref());
> - if let Some(authors) = info.authors {
> + if let Some(authors) = &info.authors {
> for author in authors {
> - modinfo.emit("author", &author);
> + modinfo.emit("author", author);
> }
> }
> - if let Some(description) = info.description {
> - modinfo.emit("description", &description);
> + if let Some(description) = &info.description {
> + modinfo.emit("description", description);
> }
> modinfo.emit("license", &info.license);
> - if let Some(aliases) = info.alias {
> + if let Some(aliases) = &info.alias {
> for alias in aliases {
> - modinfo.emit("alias", &alias);
> + modinfo.emit("alias", alias);
> }
> }
> - if let Some(firmware) = info.firmware {
> + if let Some(firmware) = &info.firmware {
> for fw in firmware {
> - modinfo.emit("firmware", &fw);
> + modinfo.emit("firmware", fw);
> }
> }
> - if let Some(imports) = info.imports_ns {
> ++ if let Some(imports) = &info.imports_ns {
> + for ns in imports {
> - modinfo.emit("import_ns", &ns);
> ++ modinfo.emit("import_ns", ns);
> + }
> + }
This last part is the only non-trivial for this conflict.
^ permalink raw reply
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