* [PATCH bpf-next] bpf: consistently use bpf_rcu_lock_held() everywhere
@ 2025-10-10 17:30 Andrii Nakryiko
2025-10-11 14:24 ` kernel test robot
0 siblings, 1 reply; 2+ messages in thread
From: Andrii Nakryiko @ 2025-10-10 17:30 UTC (permalink / raw)
To: bpf, ast, daniel, martin.lau; +Cc: andrii, kernel-team
We have many places which open-code what's now is bpf_rcu_lock_held()
macro, so replace all those places with a clean and short macro invocation.
For that, move bpf_rcu_lock_held() macro into include/linux/bpf.h.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
include/linux/bpf.h | 3 +++
include/linux/bpf_local_storage.h | 3 ---
kernel/bpf/hashtab.c | 21 +++++++--------------
kernel/bpf/helpers.c | 12 ++++--------
4 files changed, 14 insertions(+), 25 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a98c83346134..0933b3ffe74e 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2417,6 +2417,9 @@ extern const struct bpf_prog_ops bpf_offload_prog_ops;
extern const struct bpf_verifier_ops tc_cls_act_analyzer_ops;
extern const struct bpf_verifier_ops xdp_analyzer_ops;
+#define bpf_rcu_lock_held() \
+ (rcu_read_lock_held() || rcu_read_lock_trace_held() || rcu_read_lock_bh_held())
+
struct bpf_prog *bpf_prog_get(u32 ufd);
struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
bool attach_drv);
diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index ab7244d8108f..782f58feea35 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -18,9 +18,6 @@
#define BPF_LOCAL_STORAGE_CACHE_SIZE 16
-#define bpf_rcu_lock_held() \
- (rcu_read_lock_held() || rcu_read_lock_trace_held() || \
- rcu_read_lock_bh_held())
struct bpf_local_storage_map_bucket {
struct hlist_head list;
raw_spinlock_t lock;
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index c2fcd0cd51e5..2f07aaf4d732 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -669,8 +669,7 @@ static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
struct htab_elem *l;
u32 hash, key_size;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
@@ -1098,8 +1097,7 @@ static long htab_map_update_elem(struct bpf_map *map, void *key, void *value,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
@@ -1206,8 +1204,7 @@ static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
@@ -1275,8 +1272,7 @@ static long htab_map_update_elem_in_place(struct bpf_map *map, void *key,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
@@ -1338,8 +1334,7 @@ static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
@@ -1416,8 +1411,7 @@ static long htab_map_delete_elem(struct bpf_map *map, void *key)
u32 hash, key_size;
int ret;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
@@ -1452,8 +1446,7 @@ static long htab_lru_map_delete_elem(struct bpf_map *map, void *key)
u32 hash, key_size;
int ret;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
key_size = map->key_size;
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index c9fab9a356df..500e141f6d94 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -42,8 +42,7 @@
*/
BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
{
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
return (unsigned long) map->ops->map_lookup_elem(map, key);
}
@@ -59,8 +58,7 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto = {
BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
void *, value, u64, flags)
{
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
return map->ops->map_update_elem(map, key, value, flags);
}
@@ -77,8 +75,7 @@ const struct bpf_func_proto bpf_map_update_elem_proto = {
BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
{
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
return map->ops->map_delete_elem(map, key);
}
@@ -134,8 +131,7 @@ const struct bpf_func_proto bpf_map_peek_elem_proto = {
BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu)
{
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
- !rcu_read_lock_bh_held());
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
return (unsigned long) map->ops->map_lookup_percpu_elem(map, key, cpu);
}
--
2.47.3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf-next] bpf: consistently use bpf_rcu_lock_held() everywhere
2025-10-10 17:30 [PATCH bpf-next] bpf: consistently use bpf_rcu_lock_held() everywhere Andrii Nakryiko
@ 2025-10-11 14:24 ` kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2025-10-11 14:24 UTC (permalink / raw)
To: Andrii Nakryiko, bpf, ast, daniel, martin.lau
Cc: oe-kbuild-all, andrii, kernel-team
Hi Andrii,
kernel test robot noticed the following build errors:
[auto build test ERROR on bpf-next/master]
url: https://github.com/intel-lab-lkp/linux/commits/Andrii-Nakryiko/bpf-consistently-use-bpf_rcu_lock_held-everywhere/20251011-013430
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link: https://lore.kernel.org/r/20251010173021.3952776-1-andrii%40kernel.org
patch subject: [PATCH bpf-next] bpf: consistently use bpf_rcu_lock_held() everywhere
config: i386-buildonly-randconfig-001-20251011 (https://download.01.org/0day-ci/archive/20251011/202510112101.pygcEmGf-lkp@intel.com/config)
compiler: gcc-13 (Debian 13.3.0-16) 13.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251011/202510112101.pygcEmGf-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510112101.pygcEmGf-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/linux/workqueue.h:17,
from include/linux/bpf.h:11,
from include/linux/bpf_verifier.h:7,
from net/core/filter.c:21:
include/linux/bpf_local_storage.h: In function 'bpf_local_storage_lookup':
>> include/linux/bpf_local_storage.h:149:39: error: implicit declaration of function 'bpf_rcu_lock_held'; did you mean 'rcu_read_lock_held'? [-Werror=implicit-function-declaration]
149 | bpf_rcu_lock_held());
| ^~~~~~~~~~~~~~~~~
include/linux/rcupdate.h:399:53: note: in definition of macro 'RCU_LOCKDEP_WARN'
399 | if (debug_lockdep_rcu_enabled() && (c) && \
| ^
include/linux/rcupdate.h:680:9: note: in expansion of macro '__rcu_dereference_check'
680 | __rcu_dereference_check((p), __UNIQUE_ID(rcu), \
| ^~~~~~~~~~~~~~~~~~~~~~~
include/linux/bpf_local_storage.h:148:17: note: in expansion of macro 'rcu_dereference_check'
148 | sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx],
| ^~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +149 include/linux/bpf_local_storage.h
450af8d0f6be2e KP Singh 2020-08-25 129
c83597fa5dc6b3 Yonghong Song 2022-10-25 130 struct bpf_map *
c83597fa5dc6b3 Yonghong Song 2022-10-25 131 bpf_local_storage_map_alloc(union bpf_attr *attr,
08a7ce384e33e5 Martin KaFai Lau 2023-03-22 132 struct bpf_local_storage_cache *cache,
08a7ce384e33e5 Martin KaFai Lau 2023-03-22 133 bool bpf_ma);
450af8d0f6be2e KP Singh 2020-08-25 134
68bc61c26cacf1 Marco Elver 2024-02-07 135 void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage,
68bc61c26cacf1 Marco Elver 2024-02-07 136 struct bpf_local_storage_map *smap,
68bc61c26cacf1 Marco Elver 2024-02-07 137 struct bpf_local_storage_elem *selem);
68bc61c26cacf1 Marco Elver 2024-02-07 138 /* If cacheit_lockit is false, this lookup function is lockless */
68bc61c26cacf1 Marco Elver 2024-02-07 139 static inline struct bpf_local_storage_data *
450af8d0f6be2e KP Singh 2020-08-25 140 bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
450af8d0f6be2e KP Singh 2020-08-25 141 struct bpf_local_storage_map *smap,
68bc61c26cacf1 Marco Elver 2024-02-07 142 bool cacheit_lockit)
68bc61c26cacf1 Marco Elver 2024-02-07 143 {
68bc61c26cacf1 Marco Elver 2024-02-07 144 struct bpf_local_storage_data *sdata;
68bc61c26cacf1 Marco Elver 2024-02-07 145 struct bpf_local_storage_elem *selem;
68bc61c26cacf1 Marco Elver 2024-02-07 146
68bc61c26cacf1 Marco Elver 2024-02-07 147 /* Fast path (cache hit) */
68bc61c26cacf1 Marco Elver 2024-02-07 148 sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx],
68bc61c26cacf1 Marco Elver 2024-02-07 @149 bpf_rcu_lock_held());
68bc61c26cacf1 Marco Elver 2024-02-07 150 if (sdata && rcu_access_pointer(sdata->smap) == smap)
68bc61c26cacf1 Marco Elver 2024-02-07 151 return sdata;
68bc61c26cacf1 Marco Elver 2024-02-07 152
68bc61c26cacf1 Marco Elver 2024-02-07 153 /* Slow path (cache miss) */
68bc61c26cacf1 Marco Elver 2024-02-07 154 hlist_for_each_entry_rcu(selem, &local_storage->list, snode,
68bc61c26cacf1 Marco Elver 2024-02-07 155 rcu_read_lock_trace_held())
68bc61c26cacf1 Marco Elver 2024-02-07 156 if (rcu_access_pointer(SDATA(selem)->smap) == smap)
68bc61c26cacf1 Marco Elver 2024-02-07 157 break;
68bc61c26cacf1 Marco Elver 2024-02-07 158
68bc61c26cacf1 Marco Elver 2024-02-07 159 if (!selem)
68bc61c26cacf1 Marco Elver 2024-02-07 160 return NULL;
68bc61c26cacf1 Marco Elver 2024-02-07 161 if (cacheit_lockit)
68bc61c26cacf1 Marco Elver 2024-02-07 162 __bpf_local_storage_insert_cache(local_storage, smap, selem);
68bc61c26cacf1 Marco Elver 2024-02-07 163 return SDATA(selem);
68bc61c26cacf1 Marco Elver 2024-02-07 164 }
450af8d0f6be2e KP Singh 2020-08-25 165
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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