* [PATCH] sched: Proxy yields to donor tasks
@ 2025-11-06 10:40 Fernand Sieber
2025-11-06 10:57 ` Peter Zijlstra
` (2 more replies)
0 siblings, 3 replies; 26+ messages in thread
From: Fernand Sieber @ 2025-11-06 10:40 UTC (permalink / raw)
To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
rostedt, bsegall, mgorman, vschneid
Cc: linux-kernel, dwmw, jschoenh, liuyuxua
When executing a task in proxy context, handle yields as if they were
requested by the donor task.
This avoids scenario like proxy task yielding, pick next task selecting the
same previous blocked donor, running the proxy task again, etc.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fernand Sieber <sieberf@amazon.com>
---
kernel/sched/deadline.c | 2 +-
kernel/sched/ext.c | 4 ++--
kernel/sched/fair.c | 2 +-
kernel/sched/rt.c | 2 +-
kernel/sched/syscalls.c | 5 +++--
5 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 7b7671060bf9..c4402542ef44 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2143,7 +2143,7 @@ static void yield_task_dl(struct rq *rq)
* it and the bandwidth timer will wake it up and will give it
* new scheduling parameters (thanks to dl_yielded=1).
*/
- rq->curr->dl.dl_yielded = 1;
+ rq->donor->dl.dl_yielded = 1;
update_rq_clock(rq);
update_curr_dl(rq);
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index ecb251e883ea..7e0fcfdc06a2 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1474,7 +1474,7 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int deq_flags
static void yield_task_scx(struct rq *rq)
{
struct scx_sched *sch = scx_root;
- struct task_struct *p = rq->curr;
+ struct task_struct *p = rq->donor;
if (SCX_HAS_OP(sch, yield))
SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, yield, rq, p, NULL);
@@ -1485,7 +1485,7 @@ static void yield_task_scx(struct rq *rq)
static bool yield_to_task_scx(struct rq *rq, struct task_struct *to)
{
struct scx_sched *sch = scx_root;
- struct task_struct *from = rq->curr;
+ struct task_struct *from = rq->donor;
if (SCX_HAS_OP(sch, yield))
return SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, yield, rq,
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 25970dbbb279..aa58c73b0f79 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8993,7 +8993,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev, struct t
*/
static void yield_task_fair(struct rq *rq)
{
- struct task_struct *curr = rq->curr;
+ struct task_struct *curr = rq->donor;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
struct sched_entity *se = &curr->se;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 7936d4333731..fb07dcfc60a2 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1490,7 +1490,7 @@ static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
static void yield_task_rt(struct rq *rq)
{
- requeue_task_rt(rq, rq->curr, 0);
+ requeue_task_rt(rq, rq->donor, 0);
}
static int find_lowest_rq(struct task_struct *task);
diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c
index 77ae87f36e84..bf360a6fbb80 100644
--- a/kernel/sched/syscalls.c
+++ b/kernel/sched/syscalls.c
@@ -1351,7 +1351,7 @@ static void do_sched_yield(void)
rq = this_rq_lock_irq(&rf);
schedstat_inc(rq->yld_count);
- current->sched_class->yield_task(rq);
+ rq->donor->sched_class->yield_task(rq);
preempt_disable();
rq_unlock_irq(rq, &rf);
@@ -1420,12 +1420,13 @@ EXPORT_SYMBOL(yield);
*/
int __sched yield_to(struct task_struct *p, bool preempt)
{
- struct task_struct *curr = current;
+ struct task_struct *curr;
struct rq *rq, *p_rq;
int yielded = 0;
scoped_guard (raw_spinlock_irqsave, &p->pi_lock) {
rq = this_rq();
+ curr = rq->donor;
again:
p_rq = task_rq(p);
--
2.43.0
Amazon Development Centre (South Africa) (Proprietary) Limited
29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa
Registration Number: 2004 / 034463 / 07
^ permalink raw reply related [flat|nested] 26+ messages in thread* Re: [PATCH] sched: Proxy yields to donor tasks 2025-11-06 10:40 [PATCH] sched: Proxy yields to donor tasks Fernand Sieber @ 2025-11-06 10:57 ` Peter Zijlstra 2025-11-07 6:54 ` kernel test robot 2025-11-11 11:37 ` [tip: sched/core] sched/proxy: Yield the donor task tip-bot2 for Fernand Sieber 2 siblings, 0 replies; 26+ messages in thread From: Peter Zijlstra @ 2025-11-06 10:57 UTC (permalink / raw) To: Fernand Sieber Cc: mingo, juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman, vschneid, linux-kernel, dwmw, jschoenh, liuyuxua On Thu, Nov 06, 2025 at 12:40:10PM +0200, Fernand Sieber wrote: > When executing a task in proxy context, handle yields as if they were > requested by the donor task. I'll modify this to say it matches the traditional PI semantics. > This avoids scenario like proxy task yielding, pick next task selecting the > same previous blocked donor, running the proxy task again, etc. > > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Fernand Sieber <sieberf@amazon.com> Thanks, I'll add: Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202510211205.1e0f5223-lkp@intel.com Also, for now proxy and ext are mutually exclusive, but yeah, might as convert that one now too. At some point someone will have to go through all that. ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [PATCH] sched: Proxy yields to donor tasks 2025-11-06 10:40 [PATCH] sched: Proxy yields to donor tasks Fernand Sieber 2025-11-06 10:57 ` Peter Zijlstra @ 2025-11-07 6:54 ` kernel test robot 2025-11-07 8:12 ` Fernand Sieber 2025-11-11 11:37 ` [tip: sched/core] sched/proxy: Yield the donor task tip-bot2 for Fernand Sieber 2 siblings, 1 reply; 26+ messages in thread From: kernel test robot @ 2025-11-07 6:54 UTC (permalink / raw) To: Fernand Sieber, mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman, vschneid Cc: oe-kbuild-all, linux-kernel, dwmw, jschoenh, liuyuxua Hi Fernand, kernel test robot noticed the following build warnings: [auto build test WARNING on tip/sched/core] [also build test WARNING on linus/master v6.18-rc4 next-20251107] [cannot apply to peterz-queue/sched/core] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Fernand-Sieber/sched-Proxy-yields-to-donor-tasks/20251106-184337 base: tip/sched/core patch link: https://lore.kernel.org/r/20251106104022.195157-1-sieberf%40amazon.com patch subject: [PATCH] sched: Proxy yields to donor tasks config: arm64-randconfig-r131-20251107 (https://download.01.org/0day-ci/archive/20251107/202511071431.9PLsHNo5-lkp@intel.com/config) compiler: aarch64-linux-gcc (GCC) 9.5.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251107/202511071431.9PLsHNo5-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/202511071431.9PLsHNo5-lkp@intel.com/ sparse warnings: (new ones prefixed by >>) kernel/sched/fair.c:1167:49: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct task_struct *running @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/fair.c:1167:49: sparse: expected struct task_struct *running kernel/sched/fair.c:1167:49: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/fair.c:1201:33: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct sched_entity *se @@ got struct sched_entity [noderef] __rcu * @@ kernel/sched/fair.c:1201:33: sparse: expected struct sched_entity *se kernel/sched/fair.c:1201:33: sparse: got struct sched_entity [noderef] __rcu * kernel/sched/fair.c:1259:34: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct sched_entity const *se @@ got struct sched_entity [noderef] __rcu * @@ kernel/sched/fair.c:1259:34: sparse: expected struct sched_entity const *se kernel/sched/fair.c:1259:34: sparse: got struct sched_entity [noderef] __rcu * kernel/sched/fair.c:12848:9: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] sd @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/fair.c:12848:9: sparse: expected struct sched_domain *[assigned] sd kernel/sched/fair.c:12848:9: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/fair.c:7012:58: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/fair.c:7012:58: sparse: expected struct task_struct *p kernel/sched/fair.c:7012:58: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/fair.c:6072:22: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/fair.c:6072:22: sparse: struct task_struct [noderef] __rcu * kernel/sched/fair.c:6072:22: sparse: struct task_struct * kernel/sched/fair.c:8397:20: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] sd @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/fair.c:8397:20: sparse: expected struct sched_domain *[assigned] sd kernel/sched/fair.c:8397:20: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/fair.c:8601:9: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] tmp @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/fair.c:8601:9: sparse: expected struct sched_domain *[assigned] tmp kernel/sched/fair.c:8601:9: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/fair.c:8734:39: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct task_struct *donor @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/fair.c:8734:39: sparse: expected struct task_struct *donor kernel/sched/fair.c:8734:39: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/fair.c:8766:37: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *tsk @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/fair.c:8766:37: sparse: expected struct task_struct *tsk kernel/sched/fair.c:8766:37: sparse: got struct task_struct [noderef] __rcu *curr >> kernel/sched/fair.c:8983:38: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct task_struct *curr @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/fair.c:8983:38: sparse: expected struct task_struct *curr kernel/sched/fair.c:8983:38: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/fair.c:10020:40: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct sched_domain *child @@ got struct sched_domain [noderef] __rcu *child @@ kernel/sched/fair.c:10020:40: sparse: expected struct sched_domain *child kernel/sched/fair.c:10020:40: sparse: got struct sched_domain [noderef] __rcu *child kernel/sched/fair.c:10648:22: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/fair.c:10648:22: sparse: struct task_struct [noderef] __rcu * kernel/sched/fair.c:10648:22: sparse: struct task_struct * kernel/sched/fair.c:12093:9: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] sd @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/fair.c:12093:9: sparse: expected struct sched_domain *[assigned] sd kernel/sched/fair.c:12093:9: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/fair.c:11743:44: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct sched_domain *sd_parent @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/fair.c:11743:44: sparse: expected struct sched_domain *sd_parent kernel/sched/fair.c:11743:44: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/fair.c:12208:9: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] sd @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/fair.c:12208:9: sparse: expected struct sched_domain *[assigned] sd kernel/sched/fair.c:12208:9: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/fair.c: note: in included file: kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/sched.h:2625:9: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2625:9: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2625:9: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/sched.h:2281:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2281:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2281:25: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * -- kernel/sched/rt.c:976:39: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/rt.c:1493:31: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/rt.c:1493:31: sparse: expected struct task_struct *p kernel/sched/rt.c:1493:31: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/rt.c:1809:9: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] sd @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/rt.c:1809:9: sparse: expected struct sched_domain *[assigned] sd kernel/sched/rt.c:1809:9: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/rt.c:1512:14: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct task_struct *curr @@ got struct task_struct [noderef] __rcu * @@ kernel/sched/rt.c:1512:14: sparse: expected struct task_struct *curr kernel/sched/rt.c:1512:14: sparse: got struct task_struct [noderef] __rcu * kernel/sched/rt.c:1513:15: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct task_struct *donor @@ got struct task_struct [noderef] __rcu * @@ kernel/sched/rt.c:1513:15: sparse: expected struct task_struct *donor kernel/sched/rt.c:1513:15: sparse: got struct task_struct [noderef] __rcu * kernel/sched/rt.c:1574:45: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/rt.c:1574:45: sparse: expected struct task_struct *p kernel/sched/rt.c:1574:45: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/rt.c:1616:39: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct task_struct *donor @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/rt.c:1616:39: sparse: expected struct task_struct *donor kernel/sched/rt.c:1616:39: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/rt.c:1635:64: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *tsk @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/rt.c:1635:64: sparse: expected struct task_struct *tsk kernel/sched/rt.c:1635:64: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/rt.c:1976:40: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *task @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/rt.c:1976:40: sparse: expected struct task_struct *task kernel/sched/rt.c:1976:40: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/rt.c:1999:13: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/rt.c:1999:13: sparse: struct task_struct * kernel/sched/rt.c:1999:13: sparse: struct task_struct [noderef] __rcu * kernel/sched/rt.c:2345:54: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *tsk @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/rt.c:2345:54: sparse: expected struct task_struct *tsk kernel/sched/rt.c:2345:54: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/rt.c:2347:40: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/rt.c:2347:40: sparse: expected struct task_struct *p kernel/sched/rt.c:2347:40: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/rt.c:2347:62: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/rt.c:2347:62: sparse: expected struct task_struct *p kernel/sched/rt.c:2347:62: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/build_policy.c: note: in included file: kernel/sched/deadline.c:2677:23: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/deadline.c:2677:23: sparse: expected struct task_struct *p kernel/sched/deadline.c:2677:23: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/deadline.c:2687:13: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/deadline.c:2687:13: sparse: struct task_struct * kernel/sched/deadline.c:2687:13: sparse: struct task_struct [noderef] __rcu * kernel/sched/deadline.c:2793:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/deadline.c:2793:25: sparse: struct task_struct * kernel/sched/deadline.c:2793:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/deadline.c:2295:42: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct sched_dl_entity const *b @@ got struct sched_dl_entity [noderef] __rcu * @@ kernel/sched/deadline.c:2295:42: sparse: expected struct sched_dl_entity const *b kernel/sched/deadline.c:2295:42: sparse: got struct sched_dl_entity [noderef] __rcu * kernel/sched/deadline.c:2305:38: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *tsk @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/deadline.c:2305:38: sparse: expected struct task_struct *tsk kernel/sched/deadline.c:2305:38: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/deadline.c:1194:39: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/deadline.c:1194:39: sparse: expected struct task_struct *p kernel/sched/deadline.c:1194:39: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/deadline.c:1194:85: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct sched_dl_entity const *b @@ got struct sched_dl_entity [noderef] __rcu * @@ kernel/sched/deadline.c:1194:85: sparse: expected struct sched_dl_entity const *b kernel/sched/deadline.c:1194:85: sparse: got struct sched_dl_entity [noderef] __rcu * kernel/sched/deadline.c:1292:23: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/deadline.c:1292:23: sparse: expected struct task_struct *p kernel/sched/deadline.c:1292:23: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/deadline.c:1590:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/deadline.c:1590:31: sparse: expected struct task_struct *p kernel/sched/deadline.c:1590:31: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/deadline.c:1590:70: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct sched_dl_entity const *b @@ got struct sched_dl_entity [noderef] __rcu * @@ kernel/sched/deadline.c:1590:70: sparse: expected struct sched_dl_entity const *b kernel/sched/deadline.c:1590:70: sparse: got struct sched_dl_entity [noderef] __rcu * kernel/sched/deadline.c:1703:39: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct task_struct *donor @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/deadline.c:1703:39: sparse: expected struct task_struct *donor kernel/sched/deadline.c:1703:39: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/deadline.c:2513:9: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct sched_domain *[assigned] sd @@ got struct sched_domain [noderef] __rcu *parent @@ kernel/sched/deadline.c:2513:9: sparse: expected struct sched_domain *[assigned] sd kernel/sched/deadline.c:2513:9: sparse: got struct sched_domain [noderef] __rcu *parent kernel/sched/deadline.c:2181:14: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct task_struct *curr @@ got struct task_struct [noderef] __rcu * @@ kernel/sched/deadline.c:2181:14: sparse: expected struct task_struct *curr kernel/sched/deadline.c:2181:14: sparse: got struct task_struct [noderef] __rcu * kernel/sched/deadline.c:2182:15: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct task_struct *donor @@ got struct task_struct [noderef] __rcu * @@ kernel/sched/deadline.c:2182:15: sparse: expected struct task_struct *donor kernel/sched/deadline.c:2182:15: sparse: got struct task_struct [noderef] __rcu * kernel/sched/deadline.c:2257:43: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/deadline.c:2257:43: sparse: expected struct task_struct *p kernel/sched/deadline.c:2257:43: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/deadline.c:2838:38: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *tsk @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/deadline.c:2838:38: sparse: expected struct task_struct *tsk kernel/sched/deadline.c:2838:38: sparse: got struct task_struct [noderef] __rcu *curr kernel/sched/deadline.c:2840:23: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/deadline.c:2840:23: sparse: expected struct task_struct *p kernel/sched/deadline.c:2840:23: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/deadline.c:2842:44: sparse: sparse: incorrect type in argument 2 (different address spaces) @@ expected struct sched_dl_entity const *b @@ got struct sched_dl_entity [noderef] __rcu * @@ kernel/sched/deadline.c:2842:44: sparse: expected struct sched_dl_entity const *b kernel/sched/deadline.c:2842:44: sparse: got struct sched_dl_entity [noderef] __rcu * kernel/sched/deadline.c:3036:23: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/deadline.c:3036:23: sparse: struct task_struct [noderef] __rcu * kernel/sched/deadline.c:3036:23: sparse: struct task_struct * kernel/sched/deadline.c:3083:32: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *p @@ got struct task_struct [noderef] __rcu *curr @@ kernel/sched/build_policy.c: note: in included file: kernel/sched/syscalls.c:185:22: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/syscalls.c:185:22: sparse: struct task_struct [noderef] __rcu * kernel/sched/syscalls.c:185:22: sparse: struct task_struct * >> kernel/sched/syscalls.c:1397:22: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct task_struct *curr @@ got struct task_struct [noderef] __rcu *donor @@ kernel/sched/syscalls.c:1397:22: sparse: expected struct task_struct *curr kernel/sched/syscalls.c:1397:22: sparse: got struct task_struct [noderef] __rcu *donor kernel/sched/build_policy.c: note: in included file: kernel/sched/sched.h:2281:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2281:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2281:25: sparse: struct task_struct * kernel/sched/sched.h:2281:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2281:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2281:25: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/sched.h:2281:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2281:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2281:25: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/sched.h:2281:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2281:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2281:25: sparse: struct task_struct * kernel/sched/sched.h:2281:25: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2281:25: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2281:25: sparse: struct task_struct * kernel/sched/sched.h:2292:26: sparse: sparse: incompatible types in comparison expression (different address spaces): kernel/sched/sched.h:2292:26: sparse: struct task_struct [noderef] __rcu * kernel/sched/sched.h:2292:26: sparse: struct task_struct * kernel/sched/build_policy.c: note: in included file: kernel/sched/syscalls.c:1257:6: sparse: sparse: context imbalance in 'sched_getaffinity' - wrong count at exit kernel/sched/syscalls.c:1322:11: sparse: sparse: dereference of noderef expression kernel/sched/build_policy.c: note: in included file: kernel/sched/rt.c:1659:15: sparse: sparse: dereference of noderef expression vim +8983 kernel/sched/fair.c 8977 8978 /* 8979 * sched_yield() is very simple 8980 */ 8981 static void yield_task_fair(struct rq *rq) 8982 { > 8983 struct task_struct *curr = rq->donor; 8984 struct cfs_rq *cfs_rq = task_cfs_rq(curr); 8985 struct sched_entity *se = &curr->se; 8986 8987 /* 8988 * Are we the only task in the tree? 8989 */ 8990 if (unlikely(rq->nr_running == 1)) 8991 return; 8992 8993 clear_buddies(cfs_rq, se); 8994 8995 update_rq_clock(rq); 8996 /* 8997 * Update run-time statistics of the 'current'. 8998 */ 8999 update_curr(cfs_rq); 9000 /* 9001 * Tell update_rq_clock() that we've just updated, 9002 * so we don't do microscopic update in schedule() 9003 * and double the fastpath cost. 9004 */ 9005 rq_clock_skip_update(rq); 9006 9007 /* 9008 * Forfeit the remaining vruntime, only if the entity is eligible. This 9009 * condition is necessary because in core scheduling we prefer to run 9010 * ineligible tasks rather than force idling. If this happens we may 9011 * end up in a loop where the core scheduler picks the yielding task, 9012 * which yields immediately again; without the condition the vruntime 9013 * ends up quickly running away. 9014 */ 9015 if (entity_eligible(cfs_rq, se)) { 9016 se->vruntime = se->deadline; 9017 se->deadline += calc_delta_fair(se->slice, se); 9018 update_min_vruntime(cfs_rq); 9019 } 9020 } 9021 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [PATCH] sched: Proxy yields to donor tasks 2025-11-07 6:54 ` kernel test robot @ 2025-11-07 8:12 ` Fernand Sieber 2025-11-07 8:25 ` Peter Zijlstra 0 siblings, 1 reply; 26+ messages in thread From: Fernand Sieber @ 2025-11-07 8:12 UTC (permalink / raw) To: kernel test robot, mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman, vschneid Cc: oe-kbuild-all, linux-kernel, dwmw, jschoenh, liuyuxua On Thu, Nov 07, 2025 at 02:31:16PM +0800, kernel test robot wrote: > sparse warnings: (new ones prefixed by >>) > >>> kernel/sched/rt.c:529:55: sparse: warning: incorrect type in initializer (different address spaces) >>> kernel/sched/rt.c:976:39: sparse: warning: incorrect type in initializer (different address spaces) Thank you for the report. The warnings occur because my patch changes scheduler yield functions from accessing rq->curr to rq->donor, both of which have identical __rcu annotations. These are pre-existing annotation issues in the scheduler code, which has been directly accessing RCU-annotated pointers without proper dereferencing, relying on runqueue lock protection instead. If we do want to address these sparse warnings, I can make modifications like: - curr = rq->donor; + curr = rcu_dereference_protected(rq->donor, lockdep_is_held(&rq->__lock)); This would have zero runtime overhead while satisfying sparse's RCU checking. Peter, let me know if these warnings should be addressed. Thanks, Fernand Amazon Development Centre (South Africa) (Proprietary) Limited 29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa Registration Number: 2004 / 034463 / 07 ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [PATCH] sched: Proxy yields to donor tasks 2025-11-07 8:12 ` Fernand Sieber @ 2025-11-07 8:25 ` Peter Zijlstra 0 siblings, 0 replies; 26+ messages in thread From: Peter Zijlstra @ 2025-11-07 8:25 UTC (permalink / raw) To: Fernand Sieber Cc: kernel test robot, mingo, juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman, vschneid, oe-kbuild-all, linux-kernel, dwmw, jschoenh, liuyuxua On Fri, Nov 07, 2025 at 10:12:53AM +0200, Fernand Sieber wrote: > On Thu, Nov 07, 2025 at 02:31:16PM +0800, kernel test robot wrote: > > sparse warnings: (new ones prefixed by >>) > > > >>> kernel/sched/rt.c:529:55: sparse: warning: incorrect type in initializer (different address spaces) > >>> kernel/sched/rt.c:976:39: sparse: warning: incorrect type in initializer (different address spaces) > > Thank you for the report. > > The warnings occur because my patch changes scheduler yield functions from > accessing rq->curr to rq->donor, both of which have identical __rcu annotations. > These are pre-existing annotation issues in the scheduler code, which has been > directly accessing RCU-annotated pointers without proper dereferencing, relying > on runqueue lock protection instead. > > If we do want to address these sparse warnings, I can make modifications like: > > - curr = rq->donor; > + curr = rcu_dereference_protected(rq->donor, lockdep_is_held(&rq->__lock)); > > This would have zero runtime overhead while satisfying sparse's RCU checking. > > Peter, let me know if these warnings should be addressed. Nah, I'm happy to ignore them to retain readable code :-) ^ permalink raw reply [flat|nested] 26+ messages in thread
* [tip: sched/core] sched/proxy: Yield the donor task 2025-11-06 10:40 [PATCH] sched: Proxy yields to donor tasks Fernand Sieber 2025-11-06 10:57 ` Peter Zijlstra 2025-11-07 6:54 ` kernel test robot @ 2025-11-11 11:37 ` tip-bot2 for Fernand Sieber 2 siblings, 0 replies; 26+ messages in thread From: tip-bot2 for Fernand Sieber @ 2025-11-11 11:37 UTC (permalink / raw) To: linux-tip-commits Cc: kernel test robot, Peter Zijlstra, Fernand Sieber, x86, linux-kernel The following commit has been merged into the sched/core branch of tip: Commit-ID: 127b90315ca07ccad2618db7ba950a63e3b32d22 Gitweb: https://git.kernel.org/tip/127b90315ca07ccad2618db7ba950a63e3b32d22 Author: Fernand Sieber <sieberf@amazon.com> AuthorDate: Thu, 06 Nov 2025 12:40:10 +02:00 Committer: Peter Zijlstra <peterz@infradead.org> CommitterDate: Tue, 11 Nov 2025 12:33:36 +01:00 sched/proxy: Yield the donor task When executing a task in proxy context, handle yields as if they were requested by the donor task. This matches the traditional PI semantics of yield() as well. This avoids scenario like proxy task yielding, pick next task selecting the same previous blocked donor, running the proxy task again, etc. Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202510211205.1e0f5223-lkp@intel.com Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Fernand Sieber <sieberf@amazon.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251106104022.195157-1-sieberf@amazon.com --- kernel/sched/deadline.c | 2 +- kernel/sched/ext.c | 4 ++-- kernel/sched/fair.c | 2 +- kernel/sched/rt.c | 2 +- kernel/sched/syscalls.c | 5 +++-- 5 files changed, 8 insertions(+), 7 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 6b8a928..13112c6 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2143,7 +2143,7 @@ static void yield_task_dl(struct rq *rq) * it and the bandwidth timer will wake it up and will give it * new scheduling parameters (thanks to dl_yielded=1). */ - rq->curr->dl.dl_yielded = 1; + rq->donor->dl.dl_yielded = 1; update_rq_clock(rq); update_curr_dl(rq); diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index b063444..224b72c 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -1474,7 +1474,7 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int deq_flags static void yield_task_scx(struct rq *rq) { struct scx_sched *sch = scx_root; - struct task_struct *p = rq->curr; + struct task_struct *p = rq->donor; if (SCX_HAS_OP(sch, yield)) SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, yield, rq, p, NULL); @@ -1485,7 +1485,7 @@ static void yield_task_scx(struct rq *rq) static bool yield_to_task_scx(struct rq *rq, struct task_struct *to) { struct scx_sched *sch = scx_root; - struct task_struct *from = rq->curr; + struct task_struct *from = rq->donor; if (SCX_HAS_OP(sch, yield)) return SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, yield, rq, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 273e287..f1d8eb3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8980,7 +8980,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev, struct t */ static void yield_task_fair(struct rq *rq) { - struct task_struct *curr = rq->curr; + struct task_struct *curr = rq->donor; struct cfs_rq *cfs_rq = task_cfs_rq(curr); struct sched_entity *se = &curr->se; diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 1fd97f2..f1867fe 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1490,7 +1490,7 @@ static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head) static void yield_task_rt(struct rq *rq) { - requeue_task_rt(rq, rq->curr, 0); + requeue_task_rt(rq, rq->donor, 0); } static int find_lowest_rq(struct task_struct *task); diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c index 8f0f603..8078791 100644 --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -1319,7 +1319,7 @@ static void do_sched_yield(void) rq = this_rq_lock_irq(&rf); schedstat_inc(rq->yld_count); - current->sched_class->yield_task(rq); + rq->donor->sched_class->yield_task(rq); preempt_disable(); rq_unlock_irq(rq, &rf); @@ -1388,12 +1388,13 @@ EXPORT_SYMBOL(yield); */ int __sched yield_to(struct task_struct *p, bool preempt) { - struct task_struct *curr = current; + struct task_struct *curr; struct rq *rq, *p_rq; int yielded = 0; scoped_guard (raw_spinlock_irqsave, &p->pi_lock) { rq = this_rq(); + curr = rq->donor; again: p_rq = task_rq(p); ^ permalink raw reply related [flat|nested] 26+ messages in thread
* [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address
@ 2025-10-21 5:14 kernel test robot
2025-10-21 6:39 ` Chen, Yu C
` (2 more replies)
0 siblings, 3 replies; 26+ messages in thread
From: kernel test robot @ 2025-10-21 5:14 UTC (permalink / raw)
To: Fernand Sieber
Cc: oe-lkp, lkp, linux-kernel, x86, Peter Zijlstra, aubrey.li,
yu.c.chen, oliver.sang
Hello,
kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield")
https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core
[test failed on linux-next/master 606da5bb165594c052ee11de79bf05bc38bc1aa6]
in testcase: trinity
version:
with following parameters:
runtime: 300s
group: group-04
nr_groups: 5
config: x86_64-randconfig-121-20251020
compiler: gcc-13
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
(please refer to attached dmesg/kmsg for entire log/backtrace)
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 <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202510211205.1e0f5223-lkp@intel.com
[ 23.486344][ T3682] BUG: kernel NULL pointer dereference, address: 0000000000000051
[ 23.486846][ T3682] #PF: supervisor read access in kernel mode
[ 23.487189][ T3682] #PF: error_code(0x0000) - not-present page
[ 23.487532][ T3682] PGD 12b0a5067 P4D 12b0a5067 PUD 12b0b0067 PMD 0
[ 23.487905][ T3682] Oops: Oops: 0000 [#1]
[ 23.488147][ T3682] CPU: 0 UID: 65534 PID: 3682 Comm: trinity-c1 Not tainted 6.18.0-rc1-00001-g79104becf42b #1 PREEMPT
[ 23.488817][ T3682] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 23.489401][ T3682] RIP: 0010:pick_task_fair (kernel/sched/fair.c:5526 kernel/sched/fair.c:8846)
[ 23.490438][ T3682] Code: d2 74 1a 4c 89 d6 4c 89 e7 e8 8d e9 ff ff 85 c0 74 0b 41 80 7a 51 00 74 31 0f 0b eb 2d be 01 00 00 00 4c 89 e7 e8 b5 fe ff ff <80> 78 51 00 49 89 c2 74 12 ba 01 02 00 00 48 89 c6 48 89 df e8 44
All code
========
0: d2 74 1a 4c shlb %cl,0x4c(%rdx,%rbx,1)
4: 89 d6 mov %edx,%esi
6: 4c 89 e7 mov %r12,%rdi
9: e8 8d e9 ff ff call 0xffffffffffffe99b
e: 85 c0 test %eax,%eax
10: 74 0b je 0x1d
12: 41 80 7a 51 00 cmpb $0x0,0x51(%r10)
17: 74 31 je 0x4a
19: 0f 0b ud2
1b: eb 2d jmp 0x4a
1d: be 01 00 00 00 mov $0x1,%esi
22: 4c 89 e7 mov %r12,%rdi
25: e8 b5 fe ff ff call 0xfffffffffffffedf
2a:* 80 78 51 00 cmpb $0x0,0x51(%rax) <-- trapping instruction
2e: 49 89 c2 mov %rax,%r10
31: 74 12 je 0x45
33: ba 01 02 00 00 mov $0x201,%edx
38: 48 89 c6 mov %rax,%rsi
3b: 48 89 df mov %rbx,%rdi
3e: e8 .byte 0xe8
3f: 44 rex.R
Code starting with the faulting instruction
===========================================
0: 80 78 51 00 cmpb $0x0,0x51(%rax)
4: 49 89 c2 mov %rax,%r10
7: 74 12 je 0x1b
9: ba 01 02 00 00 mov $0x201,%edx
e: 48 89 c6 mov %rax,%rsi
11: 48 89 df mov %rbx,%rdi
14: e8 .byte 0xe8
15: 44 rex.R
[ 23.491525][ T3682] RSP: 0000:ffff88812640fdf0 EFLAGS: 00010046
[ 23.491870][ T3682] RAX: 0000000000000000 RBX: ffffffff8306f580 RCX: 000000004d636517
[ 23.492330][ T3682] RDX: 000000004d636517 RSI: 000000005572ffec RDI: ffffffff8306f600
[ 23.492786][ T3682] RBP: ffff88812640fe00 R08: 000000000000000f R09: 0000000000000002
[ 23.493232][ T3682] R10: 0000000000000000 R11: ffff8881264140c0 R12: ffffffff8306f600
[ 23.493679][ T3682] R13: ffff888125cf0000 R14: ffff88812640fe58 R15: ffff888126414788
[ 23.494125][ T3682] FS: 0000000000000000(0000) GS:0000000000000000(0063) knlGS:0000000008e97880
[ 23.494627][ T3682] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
[ 23.494999][ T3682] CR2: 0000000000000051 CR3: 000000012b09c000 CR4: 00000000000406b0
[ 23.495447][ T3682] Call Trace:
[ 23.495637][ T3682] <TASK>
[ 23.495807][ T3682] pick_next_task_fair (kernel/sched/fair.c:8869)
[ 23.496095][ T3682] __schedule (kernel/sched/core.c:5969 kernel/sched/core.c:6488 kernel/sched/core.c:6870)
[ 23.496349][ T3682] ? raw_spin_rq_unlock (kernel/sched/core.c:683)
[ 23.496640][ T3682] schedule (arch/x86/include/asm/bitops.h:202 (discriminator 1) arch/x86/include/asm/bitops.h:232 (discriminator 1) include/linux/thread_info.h:192 (discriminator 1) include/linux/thread_info.h:208 (discriminator 1) include/linux/sched.h:2217 (discriminator 1) kernel/sched/core.c:7013 (discriminator 1) kernel/sched/core.c:7026 (discriminator 1))
[ 23.496868][ T3682] do_sched_yield (kernel/sched/syscalls.c:1361)
[ 23.497127][ T3682] __do_sys_sched_yield (kernel/sched/syscalls.c:1375)
[ 23.497409][ T3682] ia32_sys_call (kbuild/obj/consumer/x86_64-randconfig-121-20251020/./arch/x86/include/generated/asm/syscalls_32.h:159)
[ 23.497681][ T3682] do_int80_emulation (arch/x86/entry/syscall_32.c:83 arch/x86/entry/syscall_32.c:172)
[ 23.497962][ T3682] asm_int80_emulation (arch/x86/include/asm/idtentry.h:569)
[ 23.498244][ T3682] RIP: 0023:0xf7f3c579
[ 23.498477][ T3682] Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 0f 1f 40 00 cd 80 <5d> 5a 59 c3 90 90 90 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00
All code
========
0: b8 01 10 06 03 mov $0x3061001,%eax
5: 74 b4 je 0xffffffffffffffbb
7: 01 10 add %edx,(%rax)
9: 07 (bad)
a: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
e: 10 08 adc %cl,(%rax)
10: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
...
20: 00 51 52 add %dl,0x52(%rcx)
23: 55 push %rbp
24: 0f 1f 40 00 nopl 0x0(%rax)
28: cd 80 int $0x80
2a:* 5d pop %rbp <-- trapping instruction
2b: 5a pop %rdx
2c: 59 pop %rcx
2d: c3 ret
2e: 90 nop
2f: 90 nop
30: 90 nop
31: 90 nop
32: 2e 8d b4 26 00 00 00 cs lea 0x0(%rsi,%riz,1),%esi
39: 00
3a: 8d .byte 0x8d
3b: b4 26 mov $0x26,%ah
3d: 00 00 add %al,(%rax)
...
Code starting with the faulting instruction
===========================================
0: 5d pop %rbp
1: 5a pop %rdx
2: 59 pop %rcx
3: c3 ret
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 2e 8d b4 26 00 00 00 cs lea 0x0(%rsi,%riz,1),%esi
f: 00
10: 8d .byte 0x8d
11: b4 26 mov $0x26,%ah
13: 00 00 add %al,(%rax)
...
[ 23.499561][ T3682] RSP: 002b:00000000ffd6080c EFLAGS: 00000292 ORIG_RAX: 000000000000009e
[ 23.500032][ T3682] RAX: ffffffffffffffda RBX: 00000000edededed RCX: 00000000e16628f4
[ 23.500494][ T3682] RDX: 00000000000000e4 RSI: 00000000c25418ab RDI: 00000000810000d8
[ 23.500940][ T3682] RBP: 0000000000002424 R08: 0000000000000000 R09: 0000000000000000
[ 23.501386][ T3682] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 23.501832][ T3682] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 23.502281][ T3682] </TASK>
[ 23.502457][ T3682] Modules linked in:
[ 23.502681][ T3682] CR2: 0000000000000051
[ 23.502918][ T3682] ---[ end trace 0000000000000000 ]---
[ 23.503228][ T3682] RIP: 0010:pick_task_fair (kernel/sched/fair.c:5526 kernel/sched/fair.c:8846)
[ 23.503528][ T3682] Code: d2 74 1a 4c 89 d6 4c 89 e7 e8 8d e9 ff ff 85 c0 74 0b 41 80 7a 51 00 74 31 0f 0b eb 2d be 01 00 00 00 4c 89 e7 e8 b5 fe ff ff <80> 78 51 00 49 89 c2 74 12 ba 01 02 00 00 48 89 c6 48 89 df e8 44
All code
========
0: d2 74 1a 4c shlb %cl,0x4c(%rdx,%rbx,1)
4: 89 d6 mov %edx,%esi
6: 4c 89 e7 mov %r12,%rdi
9: e8 8d e9 ff ff call 0xffffffffffffe99b
e: 85 c0 test %eax,%eax
10: 74 0b je 0x1d
12: 41 80 7a 51 00 cmpb $0x0,0x51(%r10)
17: 74 31 je 0x4a
19: 0f 0b ud2
1b: eb 2d jmp 0x4a
1d: be 01 00 00 00 mov $0x1,%esi
22: 4c 89 e7 mov %r12,%rdi
25: e8 b5 fe ff ff call 0xfffffffffffffedf
2a:* 80 78 51 00 cmpb $0x0,0x51(%rax) <-- trapping instruction
2e: 49 89 c2 mov %rax,%r10
31: 74 12 je 0x45
33: ba 01 02 00 00 mov $0x201,%edx
38: 48 89 c6 mov %rax,%rsi
3b: 48 89 df mov %rbx,%rdi
3e: e8 .byte 0xe8
3f: 44 rex.R
Code starting with the faulting instruction
===========================================
0: 80 78 51 00 cmpb $0x0,0x51(%rax)
4: 49 89 c2 mov %rax,%r10
7: 74 12 je 0x1b
9: ba 01 02 00 00 mov $0x201,%edx
e: 48 89 c6 mov %rax,%rsi
11: 48 89 df mov %rbx,%rdi
14: e8 .byte 0xe8
15: 44 rex.R
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 26+ messages in thread* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-21 5:14 [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address kernel test robot @ 2025-10-21 6:39 ` Chen, Yu C 2025-10-21 11:04 ` Peter Zijlstra 2025-11-04 21:04 ` Fernand Sieber 2 siblings, 0 replies; 26+ messages in thread From: Chen, Yu C @ 2025-10-21 6:39 UTC (permalink / raw) To: Fernand Sieber Cc: oe-lkp, lkp, linux-kernel, x86, Peter Zijlstra, aubrey.li, kernel test robot On 10/21/2025 1:14 PM, kernel test robot wrote: > > > Hello, > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on: > > commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield") > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core > > [ 23.486344][ T3682] BUG: kernel NULL pointer dereference, address: 0000000000000051 > [ 23.486846][ T3682] #PF: supervisor read access in kernel mode > [ 23.487189][ T3682] #PF: error_code(0x0000) - not-present page > [ 23.487532][ T3682] PGD 12b0a5067 P4D 12b0a5067 PUD 12b0b0067 PMD 0 > [ 23.487905][ T3682] Oops: Oops: 0000 [#1] > [ 23.488147][ T3682] CPU: 0 UID: 65534 PID: 3682 Comm: trinity-c1 Not tainted 6.18.0-rc1-00001-g79104becf42b #1 PREEMPT > [ 23.488817][ T3682] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 > [ 23.489401][ T3682] RIP: 0010:pick_task_fair (kernel/sched/fair.c:5526 kernel/sched/fair.c:8846) Take a glance at the context, it seems to break here: pick_next_entity(rq, cfs_rq) se = pick_eevdf(cfs_rq); se->sched_delayed <=== se is NULL In the original change, we force the current running se's vruntime moving forward and I guess for some reason the corresponding cfs_rq->min_vruntime moves forward too. Thus the rest se in the cfs_rq become ineligible, and pick_eevdf() return NULL. thanks, Chenyu ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-21 5:14 [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address kernel test robot 2025-10-21 6:39 ` Chen, Yu C @ 2025-10-21 11:04 ` Peter Zijlstra 2025-10-27 12:54 ` Peter Zijlstra 2025-11-04 21:04 ` Fernand Sieber 2 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-10-21 11:04 UTC (permalink / raw) To: kernel test robot Cc: Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li, yu.c.chen On Tue, Oct 21, 2025 at 01:14:36PM +0800, kernel test robot wrote: > > > Hello, > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on: > > commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield") > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core > > [test failed on linux-next/master 606da5bb165594c052ee11de79bf05bc38bc1aa6] > > in testcase: trinity > version: > with following parameters: > > runtime: 300s > group: group-04 > nr_groups: 5 > > > > config: x86_64-randconfig-121-20251020 > compiler: gcc-13 > test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > > The kernel config and materials to reproduce are available at: > https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com I'm failing at running the kernel as described in: https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/reproduce I then start the test as: root@spr:/usr/local/src/lkp-tests# bin/lkp qemu -k /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -m /usr/src/linux-2.6/tmp-build/modules.cgz /usr/src/linux-2.6/tmp-build/job-script result_root: /root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4 downloading initrds ... use local modules: /root/.lkp/cache/modules.cgz skip downloading /root/.lkp/cache/osimage/quantal/quantal-i386-core-20190426.cgz 153636 blocks skip downloading /root/.lkp/cache/osimage/pkg/quantal-i386-core.cgz/trinity-static-i386-x86_64-f93256fb_2019-08-28.cgz 48101 blocks exec command: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -fsdev local,id=test_dev,path=/root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4,security_model=none -device virtio-9p-pci,fsdev=test_dev,mount_tag=9p/virtfs_mount -kernel /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -append root=/dev/ram0 RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/vmlinuz-6.18.0-rc1-00001-g79104becf42b branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M initramfs_async=0 page_owner=on carrier_timeout=60 rcupdate.rcu_self_test=0 max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw ip=dhcp result_service=9p/virtfs_mount -initrd /root/.lkp/cache/final_initrd -smp 2 -m 16384M -no-reboot -device i6300esb -rtc base=localtime -device e1000,netdev=net0 -netdev user,id=net0 -display none -monitor null -serial stdio early console in setup code No EFI environment detected. early console in extract_kernel input_data: 0x00000000046022cc input_len: 0x0000000000ecebe2 output: 0x0000000001000000 output_len: 0x000000000446b5e8 kernel_total_size: 0x0000000003c28000 needed_size: 0x0000000004600000 trampoline_32bit: 0x0000000000000000 Decompressing Linux... No EFI environment detected. Parsing ELF... done. Booting the kernel (entry_offset: 0x000000000296dbe0). [ 0.000000][ T0] Linux version 6.18.0-rc2-00182-gbab99e58f91f (root@spr) (gcc (Debian 14.2.0-23) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44) #35 PREEMPT Tue Oct 21 13:00:08 CEST 2025 [ 0.000000][ T0] Command line: root=/dev/ram0 RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/vmlinuz-6.18.0-rc1-00001-g79104becf42b branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M initramfs_async=0 page_owner=on carrier_timeout=60 rcupdate.rcu_self_test=0 max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 sys [ 0.000000][ T0] KERNEL supported cpus: [ 0.000000][ T0] AMD AuthenticAMD [ 0.000000][ T0] Hygon HygonGenuine [ 0.000000][ T0] Centaur CentaurHauls [ 0.000000][ T0] CPU: vendor_id 'GenuineIntel' unknown, using generic init. [ 0.000000][ T0] CPU: Your system may be unstable. [ 0.000000][ T0] mce: unknown CPU type - not enabling MCE support [ 0.000000][ T0] BIOS-provided physical RAM map: [ 0.000000][ T0] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000][ T0] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved [ 0.000000][ T0] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000][ T0] BIOS-e820: [mem 0x0000000000100000-0x00000000bffdffff] usable [ 0.000000][ T0] BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] reserved [ 0.000000][ T0] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved [ 0.000000][ T0] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved [ 0.000000][ T0] BIOS-e820: [mem 0x0000000100000000-0x000000043fffffff] usable [ 0.000000][ T0] printk: debug: ignoring loglevel setting. [ 0.000000][ T0] printk: legacy bootconsole [earlyser0] enabled [ 0.000000][ T0] NX (Execute Disable) protection: active [ 0.000000][ T0] APIC: Static calls initialized [ 0.000000][ T0] SMBIOS 2.8 present. [ 0.000000][ T0] DMI: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 0.000000][ T0] DMI: Memory slots populated: 1/1 [ 0.000000][ T0] Hypervisor detected: KVM [ 0.000000][ T0] last_pfn = 0xbffe0 max_arch_pfn = 0x400000000 [ 0.000000][ T0] kvm-clock: Using msrs 4b564d01 and 4b564d00 [ 0.000001][ T0] kvm-clock: using sched offset of 202642555 cycles [ 0.000633][ T0] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns [ 0.002517][ T0] tsc: Detected 2500.000 MHz processor [ 0.003879][ T0] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved [ 0.004668][ T0] e820: remove [mem 0x000a0000-0x000fffff] usable [ 0.005338][ T0] last_pfn = 0x440000 max_arch_pfn = 0x400000000 [ 0.005997][ T0] x86/PAT: PAT support disabled because CONFIG_X86_PAT is disabled in the kernel. [ 0.006958][ T0] x86/PAT: Configuration [0-7]: WB WT UC- UC WB WT UC- UC [ 0.007765][ T0] last_pfn = 0xbffe0 max_arch_pfn = 0x400000000 [ 0.009691][ T0] RAMDISK: [mem 0xbd741000-0xbffdffff] [ 0.010263][ T0] ACPI: Early table checksum verification disabled [ 0.010942][ T0] ACPI: RSDP 0x00000000000F5280 000014 (v00 BOCHS ) [ 0.011634][ T0] ACPI: RSDT 0x00000000BFFE239C 000034 (v01 BOCHS BXPC 00000001 BXPC 00000001) [ 0.012617][ T0] ACPI: FACP 0x00000000BFFE2248 000074 (v01 BOCHS BXPC 00000001 BXPC 00000001) [ 0.013606][ T0] ACPI: DSDT 0x00000000BFFE0040 002208 (v01 BOCHS BXPC 00000001 BXPC 00000001) [ 0.014592][ T0] ACPI: FACS 0x00000000BFFE0000 000040 [ 0.015156][ T0] ACPI: APIC 0x00000000BFFE22BC 000080 (v03 BOCHS BXPC 00000001 BXPC 00000001) [ 0.016137][ T0] ACPI: HPET 0x00000000BFFE233C 000038 (v01 BOCHS BXPC 00000001 BXPC 00000001) [ 0.017119][ T0] ACPI: WAET 0x00000000BFFE2374 000028 (v01 BOCHS BXPC 00000001 BXPC 00000001) [ 0.018102][ T0] ACPI: Reserving FACP table memory at [mem 0xbffe2248-0xbffe22bb] [ 0.018921][ T0] ACPI: Reserving DSDT table memory at [mem 0xbffe0040-0xbffe2247] [ 0.019743][ T0] ACPI: Reserving FACS table memory at [mem 0xbffe0000-0xbffe003f] [ 0.020558][ T0] ACPI: Reserving APIC table memory at [mem 0xbffe22bc-0xbffe233b] [ 0.021384][ T0] ACPI: Reserving HPET table memory at [mem 0xbffe233c-0xbffe2373] [ 0.022215][ T0] ACPI: Reserving WAET table memory at [mem 0xbffe2374-0xbffe239b] [ 0.023064][ T0] Mapped APIC to ffffffffff5fd000 ( fee00000) [ 0.023798][ T0] Zone ranges: [ 0.024141][ T0] DMA [mem 0x0000000000001000-0x0000000000ffffff] [ 0.024881][ T0] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] [ 0.025626][ T0] Normal [mem 0x0000000100000000-0x000000043fffffff] [ 0.026366][ T0] Movable zone start for each node [ 0.026899][ T0] Early memory node ranges [ 0.027357][ T0] node 0: [mem 0x0000000000001000-0x000000000009efff] [ 0.028107][ T0] node 0: [mem 0x0000000000100000-0x00000000bffdffff] [ 0.028856][ T0] node 0: [mem 0x0000000100000000-0x000000043fffffff] [ 0.029612][ T0] Initmem setup node 0 [mem 0x0000000000001000-0x000000043fffffff] [ 0.030657][ T0] On node 0, zone DMA: 1 pages in unavailable ranges [ 0.031391][ T0] On node 0, zone DMA: 97 pages in unavailable ranges [ 0.082973][ T0] On node 0, zone Normal: 32 pages in unavailable ranges [ 0.083995][ T0] ACPI: PM-Timer IO Port: 0x608 [ 0.084500][ T0] CPU topo: CPU limit of 1 reached. Ignoring further CPUs [ 0.085233][ T0] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1]) [ 0.085973][ T0] IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23 [ 0.086794][ T0] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl) [ 0.087554][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 00, APIC ID 0, APIC INT 02 [ 0.088409][ T0] ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level) [ 0.089195][ T0] Int: type 0, pol 1, trig 3, bus 00, IRQ 05, APIC ID 0, APIC INT 05 [ 0.090053][ T0] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level) [ 0.090838][ T0] Int: type 0, pol 1, trig 3, bus 00, IRQ 09, APIC ID 0, APIC INT 09 [ 0.091693][ T0] ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level) [ 0.092499][ T0] Int: type 0, pol 1, trig 3, bus 00, IRQ 0a, APIC ID 0, APIC INT 0a [ 0.093350][ T0] ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level) [ 0.094168][ T0] Int: type 0, pol 1, trig 3, bus 00, IRQ 0b, APIC ID 0, APIC INT 0b [ 0.095021][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 01, APIC ID 0, APIC INT 01 [ 0.095872][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 03, APIC ID 0, APIC INT 03 [ 0.096725][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 04, APIC ID 0, APIC INT 04 [ 0.097576][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 06, APIC ID 0, APIC INT 06 [ 0.098429][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 07, APIC ID 0, APIC INT 07 [ 0.099279][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 08, APIC ID 0, APIC INT 08 [ 0.100131][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 0c, APIC ID 0, APIC INT 0c [ 0.100982][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 0d, APIC ID 0, APIC INT 0d [ 0.101905][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 0e, APIC ID 0, APIC INT 0e [ 0.102765][ T0] Int: type 0, pol 0, trig 0, bus 00, IRQ 0f, APIC ID 0, APIC INT 0f [ 0.103621][ T0] ACPI: Using ACPI (MADT) for SMP configuration information [ 0.104392][ T0] ACPI: HPET id: 0x8086a201 base: 0xfed00000 [ 0.105027][ T0] TSC deadline timer available [ 0.105872][ T0] CPU topo: Max. logical packages: 1 [ 0.106441][ T0] CPU topo: Max. logical dies: 1 [ 0.107010][ T0] CPU topo: Max. dies per package: 1 [ 0.107580][ T0] CPU topo: Max. threads per core: 1 [ 0.108148][ T0] CPU topo: Num. cores per package: 1 [ 0.108744][ T0] CPU topo: Num. threads per package: 1 [ 0.109340][ T0] CPU topo: Allowing 1 present CPUs plus 0 hotplug CPUs [ 0.110078][ T0] CPU topo: Rejected CPUs 1 [ 0.110550][ T0] mapped IOAPIC to ffffffffff5fc000 (fec00000) [ 0.111220][ T0] kvm-guest: APIC: eoi() replaced with kvm_guest_apic_eoi_write() [ 0.112073][ T0] [mem 0xc0000000-0xfeffbfff] available for PCI devices [ 0.112818][ T0] Booting paravirtualized kernel on KVM [ 0.113413][ T0] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns [ 0.114650][ T0] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768 [ 0.115320][ T0] pcpu-alloc: [0] 0 [ 0.115739][ T0] Kernel command line: root=/dev/ram0 RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/vmlinuz-6.18.0-rc1-00001-g79104becf42b branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M initramfs_async=0 page_owner=on carrier_timeout=60 rcupdate.rcu_self_test=0 max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_coun [ 0.115953][ T0] sysrq: sysrq always enabled. [ 0.126476][ T0] ignoring the deprecated load_ramdisk= option [ 0.127244][ T0] Unknown kernel command line parameters "RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 prompt_ramdisk=0 vga=normal result_service=9p/virtfs_mount", will be passed to user space. [ 0.134040][ T0] printk: log buffer data + meta data: 1048576 + 3670016 = 4718592 bytes [ 0.136891][ T0] Dentry cache hash table entries: 2097152 (order: 12, 16777216 bytes, linear) [ 0.138842][ T0] Inode-cache hash table entries: 1048576 (order: 11, 8388608 bytes, linear) [ 0.139832][ T0] software IO TLB: area num 1. [ 0.151743][ T0] Built 1 zonelists, mobility grouping on. Total pages: 4194174 [ 0.152570][ T0] mem auto-init: stack:off, heap alloc:on, heap free:off [ 0.153300][ T0] stackdepot: allocating hash table via alloc_large_system_hash [ 0.154112][ T0] stackdepot hash table entries: 1048576 (order: 12, 16777216 bytes, linear) [ 0.157072][ T0] stackdepot: allocating space for 8192 stack pools via memblock [ 0.609556][ T0] SLUB: HWalign=64, Order=0-1, MinObjects=0, CPUs=1, Nodes=1 [ 0.712011][ T0] allocated 335544320 bytes of page_ext [ 0.712595][ T0] Node 0, zone DMA: page owner found early allocated 0 pages [ 0.713807][ T0] Node 0, zone DMA32: page owner found early allocated 0 pages [ 0.733725][ T0] Node 0, zone Normal: page owner found early allocated 82012 pages [ 0.734631][ T0] [ 0.734854][ T0] ********************************************************** [ 0.735604][ T0] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** [ 0.736352][ T0] ** ** [ 0.737097][ T0] ** trace_printk() being used. Allocating extra memory. ** [ 0.737858][ T0] ** ** [ 0.738601][ T0] ** This means that this is a DEBUG kernel and it is ** [ 0.739350][ T0] ** unsafe for production use. ** [ 0.740100][ T0] ** ** [ 0.740844][ T0] ** If you see this message and you are not debugging ** [ 0.741596][ T0] ** the kernel, report this immediately to your vendor! ** [ 0.742345][ T0] ** ** [ 0.743195][ T0] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** [ 0.744148][ T0] ********************************************************** [ 0.746086][ T0] Running RCU self tests [ 0.746635][ T0] Running RCU synchronous self tests [ 0.747311][ T0] rcu: Preemptible hierarchical RCU implementation. [ 0.748149][ T0] rcu: RCU event tracing is enabled. [ 0.748869][ T0] rcu: RCU lockdep checking is enabled. [ 0.749600][ T0] RCU CPU stall warnings timeout set to 100 (rcu_cpu_stall_timeout). [ 0.750692][ T0] Trampoline variant of Tasks RCU enabled. [ 0.751440][ T0] Rude variant of Tasks RCU enabled. [ 0.752135][ T0] Tracing variant of Tasks RCU enabled. [ 0.752864][ T0] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies. [ 0.753923][ T0] Running RCU synchronous self tests [ 0.754484][ T0] RCU Tasks: Setting shift to 0 and lim to 1 rcu_task_cb_adjust=1 rcu_task_cpu_ids=1. [ 0.755458][ T0] RCU Tasks Rude: Setting shift to 0 and lim to 1 rcu_task_cb_adjust=1 rcu_task_cpu_ids=1. [ 0.756477][ T0] RCU Tasks Trace: Setting shift to 0 and lim to 1 rcu_task_cb_adjust=1 rcu_task_cpu_ids=1. [ 0.762676][ T0] NR_IRQS: 4352, nr_irqs: 48, preallocated irqs: 16 [ 0.763593][ T0] rcu: srcu_init: Setting srcu_struct sizes based on contention. [ 0.764491][ T0] printk: legacy console [ttyS0] enabled [ 0.764491][ T0] printk: legacy console [ttyS0] enabled [ 0.765654][ T0] printk: legacy bootconsole [earlyser0] disabled [ 0.765654][ T0] printk: legacy bootconsole [earlyser0] disabled [ 0.766985][ T0] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 0.767885][ T0] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 0.768398][ T0] ... MAX_LOCK_DEPTH: 48 [ 0.768922][ T0] ... MAX_LOCKDEP_KEYS: 8192 [ 0.769467][ T0] ... CLASSHASH_SIZE: 4096 [ 0.770012][ T0] ... MAX_LOCKDEP_ENTRIES: 32768 [ 0.770563][ T0] ... MAX_LOCKDEP_CHAINS: 65536 [ 0.771111][ T0] ... CHAINHASH_SIZE: 32768 [ 0.771659][ T0] memory used by lock dependency info: 6941 kB [ 0.772309][ T0] memory used for stack traces: 4224 kB [ 0.772888][ T0] per task-struct memory footprint: 2688 bytes [ 0.773532][ T0] ACPI: Core revision 20250807 [ 0.774193][ T0] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604467 ns [ 0.775447][ T0] APIC: Switch to symmetric I/O mode setup [ 0.776246][ T0] x2apic enabled [ 0.776961][ T0] APIC: Switched APIC routing to: physical x2apic [ 0.777652][ T0] Masked ExtINT on CPU#0 [ 0.778876][ T0] ENABLING IO-APIC IRQs [ 0.779317][ T0] Init IO_APIC IRQs [ 0.779730][ T0] apic 0 pin 0 not connected [ 0.780235][ T0] IOAPIC[0]: Preconfigured routing entry (0-1 -> IRQ 1 Level:0 ActiveLow:0) [ 0.781162][ T0] IOAPIC[0]: Preconfigured routing entry (0-2 -> IRQ 0 Level:0 ActiveLow:0) [ 0.782088][ T0] IOAPIC[0]: Preconfigured routing entry (0-3 -> IRQ 3 Level:0 ActiveLow:0) [ 0.783006][ T0] IOAPIC[0]: Preconfigured routing entry (0-4 -> IRQ 4 Level:0 ActiveLow:0) [ 0.783952][ T0] IOAPIC[0]: Preconfigured routing entry (0-5 -> IRQ 5 Level:1 ActiveLow:0) [ 0.784874][ T0] IOAPIC[0]: Preconfigured routing entry (0-6 -> IRQ 6 Level:0 ActiveLow:0) [ 0.785809][ T0] IOAPIC[0]: Preconfigured routing entry (0-7 -> IRQ 7 Level:0 ActiveLow:0) [ 0.786752][ T0] IOAPIC[0]: Preconfigured routing entry (0-8 -> IRQ 8 Level:0 ActiveLow:0) [ 0.787731][ T0] IOAPIC[0]: Preconfigured routing entry (0-9 -> IRQ 9 Level:1 ActiveLow:0) [ 0.788677][ T0] IOAPIC[0]: Preconfigured routing entry (0-10 -> IRQ 10 Level:1 ActiveLow:0) [ 0.789648][ T0] IOAPIC[0]: Preconfigured routing entry (0-11 -> IRQ 11 Level:1 ActiveLow:0) [ 0.790620][ T0] IOAPIC[0]: Preconfigured routing entry (0-12 -> IRQ 12 Level:0 ActiveLow:0) [ 0.791592][ T0] IOAPIC[0]: Preconfigured routing entry (0-13 -> IRQ 13 Level:0 ActiveLow:0) [ 0.792555][ T0] IOAPIC[0]: Preconfigured routing entry (0-14 -> IRQ 14 Level:0 ActiveLow:0) [ 0.793514][ T0] IOAPIC[0]: Preconfigured routing entry (0-15 -> IRQ 15 Level:0 ActiveLow:0) [ 0.794473][ T0] apic 0 pin 16 not connected [ 0.794977][ T0] apic 0 pin 17 not connected [ 0.795490][ T0] apic 0 pin 18 not connected [ 0.795994][ T0] apic 0 pin 19 not connected [ 0.796497][ T0] apic 0 pin 20 not connected [ 0.796998][ T0] apic 0 pin 21 not connected [ 0.797499][ T0] apic 0 pin 22 not connected [ 0.798007][ T0] apic 0 pin 23 not connected [ 0.798651][ T0] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 [ 0.799418][ T0] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x240939f1bb2, max_idle_ns: 440795263295 ns [ 0.800652][ T0] Calibrating delay loop (skipped) preset value.. 5000.00 BogoMIPS (lpj=10000000) [ 0.801722][ T0] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0 [ 0.802386][ T0] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0 [ 0.803120][ T0] CPU: GenuineIntel Intel Xeon E312xx (Sandy Bridge) (family: 0x6, model: 0x2a, stepping: 0x1) [ 0.804660][ T0] mitigations: Enabled attack vectors: user_kernel, user_user, SMT mitigations: auto [ 0.805677][ T0] Speculative Store Bypass: Vulnerable [ 0.806270][ T0] Spectre V2 : Vulnerable [ 0.806737][ T0] MDS: Vulnerable [ 0.807124][ T0] Spectre V1 : Mitigation: usercopy/swapgs barriers and __user pointer sanitization [ 0.808664][ T0] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers' [ 0.809589][ T0] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers' [ 0.810374][ T0] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers' [ 0.811168][ T0] x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256 [ 0.811936][ T0] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'standard' format. [ 0.843536][ T0] pid_max: default: 4096 minimum: 301 [ 0.844159][ T0] LSM: initializing lsm=capability [ 0.844746][ T0] Mount-cache hash table entries: 32768 (order: 6, 262144 bytes, linear) [ 0.845695][ T0] Mountpoint-cache hash table entries: 32768 (order: 6, 262144 bytes, linear) [ 0.847038][ T0] Running RCU synchronous self tests [ 0.847616][ T0] Running RCU synchronous self tests [ 0.848694][ T1] Performance Events: no PMU driver, software events only. [ 0.849518][ T1] signal: max sigframe size: 1776 [ 0.850120][ T1] rcu: Hierarchical SRCU implementation. [ 0.850733][ T1] rcu: Max phase no-delay instances is 1000. [ 0.851682][ T1] dyndbg: Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build [ 0.852629][ T1] NMI watchdog: Perf NMI watchdog permanently disabled [ 0.852770][ T1] Memory: 15971668K/16776696K available (17029K kernel code, 9458K rwdata, 14160K rodata, 1712K init, 17332K bss, 473328K reserved, 0K cma-reserved) [ 0.855980][ T1] devtmpfs: initialized [ 0.857608][ T1] Running RCU synchronous self tests [ 0.858203][ T1] Running RCU synchronous self tests [ 0.858874][ T1] Running RCU Tasks wait API self tests [ 0.960685][ T1] Running RCU Tasks Rude wait API self tests [ 0.961386][ T1] Running RCU Tasks Trace wait API self tests [ 0.962092][ T1] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns [ 0.963279][ T1] posixtimers hash table entries: 512 (order: 3, 40960 bytes, linear) [ 0.964181][ T1] futex hash table entries: 16 (1664 bytes on 1 NUMA nodes, total 1 KiB, linear). [ 0.964988][ T1] regulator-dummy: 2147483647 mW budge, enabled [ 0.967103][ T1] NET: Registered PF_NETLINK/PF_ROUTE protocol family [ 0.968751][ T1] DMA: preallocated 2048 KiB GFP_KERNEL pool for atomic allocations [ 0.969796][ T1] DMA: preallocated 2048 KiB GFP_KERNEL|GFP_DMA pool for atomic allocations [ 0.970900][ T1] DMA: preallocated 2048 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations [ 0.972331][ T1] thermal_sys: Registered thermal governor 'step_wise' [ 0.972333][ T1] thermal_sys: Registered thermal governor 'power_allocator' [ 0.972683][ T1] cpuidle: using governor ladder [ 0.974126][ T1] NET: Registered PF_QIPCRTR protocol family [ 0.975207][ T1] PCI: Using configuration type 1 for base access [ 0.976194][ T1] kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible. [ 0.976698][ T1] workqueue: round-robin CPU selection forced, expect performance impact [ 0.980935][ T1] gpio-f7188x: Unsupported Fintek device 0xffff [ 0.981634][ T1] gpio-f7188x: Unsupported Fintek device 0xffff [ 0.982495][ T1] ACPI: Added _OSI(Module Device) [ 0.983039][ T1] ACPI: Added _OSI(Processor Device) [ 0.983609][ T1] ACPI: Added _OSI(Processor Aggregator Device) [ 0.991782][ T1] ACPI: 1 ACPI AML tables successfully acquired and loaded [ 0.998251][ T1] ACPI: Interpreter enabled [ 0.998778][ T1] ACPI: PM: (supports S0 S3 S5) [ 0.999303][ T1] ACPI: Using IOAPIC for interrupt routing [ 1.000425][ T1] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug [ 1.004649][ T1] PCI: Using E820 reservations for host bridge windows [ 1.005674][ T1] ACPI: Enabled 2 GPEs in block 00 to 0F [ 1.024049][ T1] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) [ 1.028653][ T1] acpi PNP0A03:00: _OSC: OS supports [ASPM ClockPM Segments HPX-Type3] [ 1.029543][ T1] acpi PNP0A03:00: PCIe port services disabled; not requesting _OSC control [ 1.030482][ T1] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended configuration space under this bridge [ 1.032168][ T1] PCI host bridge to bus 0000:00 [ 1.036658][ T1] pci_bus 0000:00: root bus resource [io 0x0000-0x0cf7 window] [ 1.037490][ T1] pci_bus 0000:00: root bus resource [io 0x0d00-0xffff window] [ 1.038314][ T1] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff window] [ 1.039223][ T1] pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window] [ 1.040123][ T1] pci_bus 0000:00: root bus resource [mem 0x440000000-0x4bfffffff window] [ 1.042965][ T1] pci_bus 0000:00: root bus resource [bus 00-ff] [ 1.043711][ T1] pci 0000:00:00.0: [8086:1237] type 00 class 0x060000 conventional PCI endpoint [ 1.045348][ T1] pci 0000:00:01.0: [8086:7000] type 00 class 0x060100 conventional PCI endpoint [ 1.047259][ T1] pci 0000:00:01.1: [8086:7010] type 00 class 0x010180 conventional PCI endpoint [ 1.048680][ T1] pci 0000:00:01.1: BAR 4 [io 0xc080-0xc08f] [ 1.049354][ T1] pci 0000:00:01.1: BAR 0 [io 0x01f0-0x01f7]: legacy IDE quirk [ 1.050158][ T1] pci 0000:00:01.1: BAR 1 [io 0x03f6]: legacy IDE quirk [ 1.050913][ T1] pci 0000:00:01.1: BAR 2 [io 0x0170-0x0177]: legacy IDE quirk [ 1.051718][ T1] pci 0000:00:01.1: BAR 3 [io 0x0376]: legacy IDE quirk [ 1.052847][ T1] pci 0000:00:01.3: [8086:7113] type 00 class 0x068000 conventional PCI endpoint [ 1.054088][ T1] pci 0000:00:01.3: quirk: [io 0x0600-0x063f] claimed by PIIX4 ACPI [ 1.054955][ T1] pci 0000:00:01.3: quirk: [io 0x0700-0x070f] claimed by PIIX4 SMB [ 1.056204][ T1] pci 0000:00:02.0: [1234:1111] type 00 class 0x030000 conventional PCI endpoint [ 1.058175][ T1] pci 0000:00:02.0: BAR 0 [mem 0xfd000000-0xfdffffff pref] [ 1.058967][ T1] pci 0000:00:02.0: BAR 2 [mem 0xfebf0000-0xfebf0fff] [ 1.059712][ T1] pci 0000:00:02.0: ROM [mem 0xfebe0000-0xfebeffff pref] [ 1.060524][ T1] pci 0000:00:02.0: Video device with shadowed ROM at [mem 0x000c0000-0x000dffff] [ 1.061142][ T1] pci 0000:00:03.0: [1af4:1009] type 00 class 0x000200 conventional PCI endpoint [ 1.063556][ T1] pci 0000:00:03.0: BAR 0 [io 0xc000-0xc03f] [ 1.064269][ T1] pci 0000:00:03.0: BAR 1 [mem 0xfebf1000-0xfebf1fff] [ 1.064683][ T19] Callback from call_rcu_tasks_trace() invoked. [ 1.065639][ T1] pci 0000:00:03.0: BAR 4 [mem 0xfe000000-0xfe003fff 64bit pref] [ 1.068769][ T1] pci 0000:00:04.0: [8086:25ab] type 00 class 0x088000 conventional PCI endpoint [ 1.070216][ T1] pci 0000:00:04.0: BAR 0 [mem 0xfebf2000-0xfebf200f] [ 1.072890][ T1] pci 0000:00:05.0: [8086:100e] type 00 class 0x020000 conventional PCI endpoint [ 1.077149][ T1] pci 0000:00:05.0: BAR 0 [mem 0xfebc0000-0xfebdffff] [ 1.077900][ T1] pci 0000:00:05.0: BAR 1 [io 0xc040-0xc07f] [ 1.078575][ T1] pci 0000:00:05.0: ROM [mem 0xfeb80000-0xfebbffff pref] [ 1.081262][ T1] pci_bus 0000:00: on NUMA node 0 [ 1.082818][ T1] ACPI: PCI: Interrupt link LNKA configured for IRQ 10 [ 1.083870][ T1] ACPI: PCI: Interrupt link LNKB configured for IRQ 10 [ 1.084809][ T1] ACPI: PCI: Interrupt link LNKC configured for IRQ 11 [ 1.085893][ T1] ACPI: PCI: Interrupt link LNKD configured for IRQ 11 [ 1.087126][ T1] ACPI: PCI: Interrupt link LNKS configured for IRQ 9 [ 1.089536][ T1] iommu: Default domain type: Translated [ 1.090445][ T1] iommu: DMA domain TLB invalidation policy: lazy mode [ 1.092159][ T1] mc: Linux media interface: v0.10 [ 1.092725][ T1] videodev: Linux video capture interface: v2.00 [ 1.093690][ T1] pps_core: LinuxPPS API ver. 1 registered [ 1.094472][ T1] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it> [ 1.095560][ T1] PTP clock support registered [ 1.096124][ T1] EDAC MC: Ver: 3.0.0 [ 1.097219][ T1] FPGA manager framework [ 1.097815][ T1] Advanced Linux Sound Architecture Driver Initialized. [ 1.099568][ T1] nfc: nfc_init: NFC Core ver 0.1 [ 1.100469][ T1] NET: Registered PF_NFC protocol family [ 1.100654][ T1] mctp: management component transport protocol core [ 1.101793][ T1] NET: Registered PF_MCTP protocol family [ 1.102786][ T1] PCI: Using ACPI for IRQ routing [ 1.103618][ T1] PCI: pci_cache_line_size set to 64 bytes [ 1.104721][ T1] e820: reserve RAM buffer [mem 0x0009fc00-0x0009ffff] [ 1.105883][ T1] e820: reserve RAM buffer [mem 0xbffe0000-0xbfffffff] [ 1.107193][ T1] pci 0000:00:02.0: vgaarb: setting as boot VGA device [ 1.108333][ T1] pci 0000:00:02.0: vgaarb: bridge control possible [ 1.108646][ T1] pci 0000:00:02.0: vgaarb: VGA device added: decodes=io+mem,owns=io+mem,locks=none [ 1.108661][ T1] vgaarb: loaded [ 1.109573][ T1] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0 [ 1.110515][ T1] hpet0: 3 comparators, 64-bit 100.000000 MHz counter [ 1.114844][ T1] clocksource: Switched to clocksource kvm-clock [ 1.116646][ T1] netfs: FS-Cache loaded [ 1.116646][ T1] pnp: PnP ACPI init [ 1.116646][ T1] pnp 00:02: [dma 2] [ 1.117919][ T1] pnp: PnP ACPI: found 6 devices [ 1.124946][ T1] clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 2085701024 ns [ 1.126928][ T1] NET: Registered PF_INET protocol family [ 1.128044][ T1] IP idents hash table entries: 262144 (order: 9, 2097152 bytes, linear) [ 1.130987][ T1] tcp_listen_portaddr_hash hash table entries: 8192 (order: 7, 655360 bytes, linear) [ 1.132242][ T1] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear) [ 1.133426][ T1] TCP established hash table entries: 131072 (order: 8, 1048576 bytes, linear) [ 1.136232][ T1] TCP bind hash table entries: 65536 (order: 11, 10485760 bytes, vmalloc hugepage) [ 1.139050][ T1] TCP: Hash tables configured (established 131072 bind 65536) [ 1.140539][ T1] UDP hash table entries: 8192 (order: 8, 1572864 bytes, linear) [ 1.142143][ T1] UDP-Lite hash table entries: 8192 (order: 8, 1572864 bytes, linear) [ 1.143345][ T1] NET: Registered PF_UNIX/PF_LOCAL protocol family [ 1.144375][ T1] RPC: Registered named UNIX socket transport module. [ 1.145158][ T1] RPC: Registered udp transport module. [ 1.145817][ T1] RPC: Registered tcp transport module. [ 1.146470][ T1] RPC: Registered tcp-with-tls transport module. [ 1.147243][ T1] RPC: Registered tcp NFSv4.1 backchannel transport module. [ 1.148120][ T1] pci_bus 0000:00: resource 4 [io 0x0000-0x0cf7 window] [ 1.148926][ T1] pci_bus 0000:00: resource 5 [io 0x0d00-0xffff window] [ 1.149778][ T1] pci_bus 0000:00: resource 6 [mem 0x000a0000-0x000bffff window] [ 1.150701][ T1] pci_bus 0000:00: resource 7 [mem 0xc0000000-0xfebfffff window] [ 1.151659][ T1] pci_bus 0000:00: resource 8 [mem 0x440000000-0x4bfffffff window] [ 1.152710][ T1] pci 0000:00:01.0: PIIX3: Enabling Passive Release [ 1.153506][ T1] pci 0000:00:00.0: Limiting direct PCI/PCI transfers [ 1.154396][ T1] PCI: CLS 0 bytes, default 64 [ 1.155183][ T21] Unpacking initramfs... [ 1.280503][ T17] Callback from call_rcu_tasks() invoked. [ 1.907393][ T21] Freeing initrd memory: 41596K [ 1.907954][ T1] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) [ 1.908868][ T1] software IO TLB: mapped [mem 0x00000000b9741000-0x00000000bd741000] (64MB) [ 1.910164][ T1] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x240939f1bb2, max_idle_ns: 440795263295 ns [ 1.911763][ T1] AVX2 instructions are not detected. [ 1.912442][ T1] AVX2 or AES-NI instructions are not detected. [ 1.913208][ T1] sm3_avx_x86_64: BMI2 instruction are not detected. [ 1.914031][ T1] AVX2 or AES-NI instructions are not detected. [ 1.914815][ T1] AVX512/GFNI instructions are not detected. [ 1.924643][ T1] Key type blacklist registered [ 1.925286][ T1] workingset: timestamp_bits=62 max_order=22 bucket_order=0 [ 1.926574][ T1] jffs2: version 2.2. (NAND) (SUMMARY) © 2001-2006 Red Hat, Inc. [ 1.927611][ T1] romfs: ROMFS MTD (C) 2007 Red Hat, Inc. [ 1.928384][ T1] fuse: init (API version 7.45) [ 1.929159][ T1] orangefs_debugfs_init: called with debug mask: :none: :0: [ 1.930178][ T1] orangefs_init: module version upstream loaded [ 1.930880][ T1] 9p: Installing v9fs 9p2000 file system support [ 1.931728][ T1] cryptd: max_cpu_qlen set to 1000 [ 1.937438][ T1] NET: Registered PF_ALG protocol family [ 1.938100][ T1] Key type asymmetric registered [ 1.939341][ T1] gpio_it87: no device [ 1.940144][ T1] gpio_winbond: chip ID at 2e is ffff [ 1.940765][ T1] gpio_winbond: not an our chip [ 1.941340][ T1] gpio_winbond: chip ID at 4e is ffff [ 1.941968][ T1] gpio_winbond: not an our chip [ 1.943244][ T1] ledtrig-cpu: registered to indicate activity on CPUs [ 1.944565][ T1] hgafb: HGA card not detected. [ 1.945118][ T1] hgafb hgafb.0: probe with driver hgafb failed with error -22 [ 1.946374][ T1] uvesafb: failed to execute /sbin/v86d [ 1.947006][ T1] uvesafb: make sure that the v86d helper is installed and executable [ 1.947961][ T1] uvesafb: Getting VBE info block failed (eax=0x4f00, err=-2) [ 1.948839][ T1] uvesafb: vbe_init() failed with -22 [ 1.949460][ T1] uvesafb uvesafb.0: probe with driver uvesafb failed with error -22 [ 1.950502][ T1] IPMI message handler: version 39.2 [ 1.951145][ T1] ipmi device interface [ 1.951701][ T1] ipmi_si: IPMI System Interface driver [ 1.952506][ T1] ipmi_si: Unable to find any System Interface(s) [ 1.953244][ T1] IPMI Watchdog: driver initialized [ 1.953842][ T1] IPMI poweroff: Copyright (C) 2004 MontaVista Software - IPMI Powerdown via sys_reboot [ 1.955719][ T1] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input0 [ 1.960372][ T1] ACPI: button: Power Button [PWRF] [ 1.999202][ T1] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled [ 2.000462][ T1] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A [ 2.003204][ T1] Non-volatile memory driver v1.3 [ 2.003886][ T1] telclk_interrupt = 0xf non-mcpbl0010 hw. [ 2.004592][ T1] Hangcheck: starting hangcheck timer 0.9.1 (tick is 180 seconds, margin is 60 seconds). [ 2.006137][ T1] ACPI: bus type drm_connector registered [ 2.007143][ T1] [drm] Initialized vgem 1.0.0 for vgem on minor 0 [ 2.008565][ T1] [drm] Initialized vkms 1.0.0 for vkms on minor 1 [ 2.009512][ T1] Error: Driver 'efi-framebuffer' is already registered, aborting... [ 2.010474][ T1] Error: Driver 'vesa-framebuffer' is already registered, aborting... [ 2.011495][ T1] dummy-irq: no IRQ given. Use irq=N [ 2.012247][ T1] Silicon Labs C2 port support v. 0.51.0 - (C) 2007 Rodolfo Giometti [ 2.014307][ T1] mtdoops: mtd device (mtddev=name/number) must be supplied [ 2.015138][ T1] L440GX flash mapping: failed to find PIIX4 ISA bridge, cannot continue [ 2.016171][ T1] SBC-GXx flash: IO:0x258-0x259 MEM:0xdc000-0xdffff [ 2.017268][ T1] CAN device driver interface [ 2.017793][ T1] e1000: Intel(R) PRO/1000 Network Driver [ 2.018464][ T1] e1000: Copyright (c) 1999-2006 Intel Corporation. [ 2.021728][ T1] ACPI: \_SB_.LNKA: Enabled at IRQ 10 [ 2.343558][ T1] e1000 0000:00:05.0 eth0: (PCI:33MHz:32-bit) 52:54:00:12:34:56 [ 2.344370][ T1] e1000 0000:00:05.0 eth0: Intel(R) PRO/1000 Network Connection [ 2.345248][ T1] YAM driver version 0.8 by F1OAT/F6FBB [ 2.346947][ T1] AX.25: bpqether driver version 004 [ 2.347486][ T1] baycom_ser_hdx: (C) 1996-2000 Thomas Sailer, HB9JNX/AE4WA [ 2.347486][ T1] baycom_ser_hdx: version 0.10 [ 2.349966][ T1] hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA [ 2.350666][ T1] hdlcdrv: version 0.8 [ 2.351297][ T1] VFIO - User Level meta-driver version: 0.3 [ 2.352038][ T1] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12 [ 2.353708][ T1] serio: i8042 KBD port at 0x60,0x64 irq 1 [ 2.354560][ T1] serio: i8042 AUX port at 0x60,0x64 irq 12 [ 2.355669][ T1] mousedev: PS/2 mouse device common for all mice [ 2.357207][ T1] i2c_dev: i2c /dev entries driver [ 2.359063][ T1] ir_imon_decoder: IR iMON protocol handler initialized [ 2.359963][ T1] IR JVC protocol handler initialized [ 2.361074][ T6] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input1 [ 2.362480][ T1] IR MCE Keyboard/mouse protocol handler initialized [ 2.363266][ T1] IR RC5(x/sz) protocol handler initialized [ 2.363968][ T1] IR RC6 protocol handler initialized [ 2.364633][ T1] IR RCMM protocol handler initialized [ 2.365274][ T1] IR SANYO protocol handler initialized [ 2.365947][ T1] IR Sharp protocol handler initialized [ 2.366837][ T1] serial_ir serial_ir.0: port 03f8 already in use [ 2.367599][ T1] serial_ir serial_ir.0: use 'setserial /dev/ttySX uart none' [ 2.368537][ T1] serial_ir serial_ir.0: or compile the serial port driver as module and [ 2.369543][ T1] serial_ir serial_ir.0: make sure this module is loaded first [ 2.370463][ T1] serial_ir serial_ir.0: probe with driver serial_ir failed with error -16 [ 2.371592][ T1] Registered IR keymap rc-empty [ 2.372279][ T1] rc rc0: rc-core loopback device as /devices/virtual/rc/rc0 [ 2.373264][ T1] rc rc0: lirc_dev: driver rc-loopback registered at minor = 0, raw IR receiver, raw IR transmitter [ 2.374721][ T1] input: rc-core loopback device as /devices/virtual/rc/rc0/input4 [ 2.376188][ T1] dvbdev: DVB: registering new adapter (dvb_vidtv_bridge) [ 2.377482][ T1] i2c i2c-0: DVB: registering adapter 0 frontend 0 (Dummy demod for DVB-T/T2/C/S/S2)... [ 2.378693][ T1] dvbdev: dvb_create_media_entity: media entity 'Dummy demod for DVB-T/T2/C/S/S2' registered. [ 2.381169][ T1] dvbdev: dvb_create_media_entity: media entity 'dvb-demux' registered. [ 2.382701][ T1] vidtv vidtv.0: Successfully initialized vidtv! [ 2.383750][ T1] vim2m vim2m.0: Device registered as /dev/video0 [ 2.387934][ T1] Driver for 1-wire Dallas network protocol. [ 2.390286][ T1] f71882fg: Not a Fintek device [ 2.390879][ T1] f71882fg: Not a Fintek device [ 2.392884][ T1] sch56xx_common: Unsupported device id: 0xff [ 2.393603][ T1] sch56xx_common: Unsupported device id: 0xff [ 2.395738][ T1] acquirewdt: WDT driver for Acquire single board computer initialising [ 2.396891][ T1] acquirewdt: I/O address 0x0043 already in use [ 2.397635][ T1] acquirewdt acquirewdt: probe with driver acquirewdt failed with error -5 [ 2.398772][ T1] advantechwdt: WDT driver for Advantech single board computer initialising [ 2.400002][ T1] advantechwdt: initialized. timeout=60 sec (nowayout=0) [ 2.412197][ T1] eurotechwdt: can't misc_register on minor=130 [ 2.413024][ T1] it87_wdt: no device [ 2.413488][ T1] pc87413_wdt: Version 1.1 at io 0x2E [ 2.414129][ T1] pc87413_wdt: cannot register miscdev on minor=130 (err=-16) [ 2.415055][ T1] machzwd: MachZ ZF-Logic Watchdog driver initializing [ 2.415874][ T1] machzwd: no ZF-Logic found [ 2.416417][ T1] sbc_epx_c3: cannot register miscdev on minor=130 (err=-16) [ 2.417614][ T1] watchdog: Software Watchdog: cannot register miscdev on minor=130 (err=-16). [ 2.418656][ T1] watchdog: Software Watchdog: a legacy watchdog module is probably present. [ 2.419879][ T1] softdog: initialized. soft_noboot=0 soft_margin=60 sec soft_panic=0 (nowayout=0) [ 2.420948][ T1] softdog: soft_reboot_cmd=<not set> soft_active_on_boot=0 [ 2.422438][ T1] comedi: version 0.7.76 - http://www.comedi.org [ 2.423334][ T1] gpib_common: GPIB core driver [ 2.425229][ T1] fujitsu_tablet: Unknown (using defaults) [ 2.426021][ T1] hdaps: supported laptop not found! [ 2.426656][ T1] hdaps: driver init failed (ret=-19)! [ 2.427750][ T1] No DMI match for this platform [ 2.429041][ T1] cros_ec_lpcs: unsupported system. [ 2.434915][ T1] gnss: GNSS driver registered with major 234 [ 2.441081][ T1] snd_mtpav snd_mtpav: Motu MidiTimePiece on parallel port irq: 7 ioport: 0x378 [ 2.446929][ T1] NET: Registered PF_INET6 protocol family [ 2.448076][ T1] Segment Routing with IPv6 [ 2.448635][ T1] In-situ OAM (IOAM) with IPv6 [ 2.449216][ T1] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver [ 2.450431][ T1] NET: Registered PF_PACKET protocol family [ 2.451110][ T1] NET: Registered PF_X25 protocol family [ 2.451773][ T1] X25: Linux Version 0.2 [ 2.452289][ T1] NET: Registered PF_AX25 protocol family [ 2.452962][ T1] can: controller area network core [ 2.453595][ T1] NET: Registered PF_CAN protocol family [ 2.454260][ T1] can: raw protocol [ 2.454712][ T1] can: broadcast manager protocol [ 2.455303][ T1] can: isotp protocol (max_pdu_size 8300) [ 2.456029][ T1] NET: Registered PF_PHONET protocol family [ 2.456737][ T1] 8021q: 802.1Q VLAN Support v1.8 [ 2.457350][ T1] 9pnet: Installing 9P2000 support [ 2.457986][ T1] Key type dns_resolver registered [ 2.458678][ T1] batman_adv: B.A.T.M.A.N. advanced 2025.4 (compatibility version 15) loaded [ 2.459855][ T1] NET: Registered PF_VSOCK protocol family [ 2.460856][ T1] mce: Unable to init MCE device (rc: -5) [ 2.461768][ T1] microcode: no support for this CPU vendor [ 2.462511][ T1] ... APIC ID: 00000000 (0) [ 2.463112][ T1] ... APIC VERSION: 00050014 [ 2.463655][ T1] 0000000000000000000000000000000000000000000000000000000000000000 [ 2.464541][ T1] 0000000000000000000000000000000000000000000000000000000000000000 [ 2.464541][ T1] 0000000000000000000000000000000000000000000000000000000000001000 [ 2.464541][ T1] [ 2.466807][ T1] number of MP IRQ sources: 15. [ 2.467383][ T1] number of IO-APIC #0 registers: 24. [ 2.468041][ T1] testing the IO APIC....................... [ 2.468791][ T1] IO APIC #0...... [ 2.469222][ T1] .... register #00: 00000000 [ 2.469763][ T1] ....... : physical APIC id: 00 [ 2.470380][ T1] ....... : Delivery Type: 0 [ 2.470943][ T1] ....... : LTS : 0 [ 2.471515][ T1] .... register #01: 00170011 [ 2.472062][ T1] ....... : max redirection entries: 17 [ 2.472769][ T1] ....... : PRQ implemented: 0 [ 2.473368][ T1] ....... : IO APIC version: 11 [ 2.473976][ T1] .... register #02: 00000000 [ 2.474515][ T1] ....... : arbitration: 00 [ 2.475081][ T1] .... IRQ redirection table: [ 2.475632][ T1] IOAPIC 0: [ 2.476019][ T1] pin00, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.477083][ T1] pin01, enabled , edge , high, V(22), IRR(0), S(0), physical, D(0000), M(0) [ 2.478143][ T1] pin02, enabled , edge , high, V(30), IRR(0), S(0), physical, D(0000), M(0) [ 2.479184][ T1] pin03, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.480223][ T1] pin04, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.481273][ T1] pin05, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.482314][ T1] pin06, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.483370][ T1] pin07, enabled , edge , high, V(23), IRR(0), S(0), physical, D(0000), M(0) [ 2.488270][ T1] pin08, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.489341][ T1] pin09, enabled , level, high, V(20), IRR(0), S(0), physical, D(0000), M(0) [ 2.490433][ T1] pin0a, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.491504][ T1] pin0b, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.492560][ T1] pin0c, enabled , edge , high, V(21), IRR(0), S(0), physical, D(0000), M(0) [ 2.493609][ T1] pin0d, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.494654][ T1] pin0e, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.495692][ T1] pin0f, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.496744][ T1] pin10, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.497794][ T1] pin11, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.498857][ T1] pin12, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.499909][ T1] pin13, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.500966][ T1] pin14, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.502024][ T1] pin15, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.503110][ T1] pin16, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.504190][ T1] pin17, disabled, edge , high, V(00), IRR(0), S(0), physical, D(0000), M(0) [ 2.505248][ T1] IRQ to pin mappings: [ 2.505732][ T1] IRQ0 -> 0:2 [ 2.506139][ T1] IRQ1 -> 0:1 [ 2.506536][ T1] IRQ3 -> 0:3 [ 2.506928][ T1] IRQ4 -> 0:4 [ 2.507326][ T1] IRQ5 -> 0:5 [ 2.507717][ T1] IRQ6 -> 0:6 [ 2.508121][ T1] IRQ7 -> 0:7 [ 2.508526][ T1] IRQ8 -> 0:8 [ 2.508919][ T1] IRQ9 -> 0:9 [ 2.509320][ T1] IRQ10 -> 0:10 [ 2.509734][ T1] IRQ11 -> 0:11 [ 2.510157][ T1] IRQ12 -> 0:12 [ 2.510574][ T1] IRQ13 -> 0:13 [ 2.510985][ T1] IRQ14 -> 0:14 [ 2.511407][ T1] IRQ15 -> 0:15 [ 2.511812][ T1] .................................... done. [ 2.533822][ T1] sched_clock: Marking stable (2500002375, 32254821)->(2543852578, -11595382) [ 2.535171][ T1] debug_vm_pgtable: [debug_vm_pgtable ]: Validating architecture page table helpers [ 2.536686][ T1] Key type .fscrypt registered [ 2.537234][ T1] Key type fscrypt-provisioning registered [ 2.538002][ T1] Key type big_key registered [ 2.538558][ T1] Key type encrypted registered [ 2.542418][ T1] 8021q: adding VLAN 0 to HW filter on device eth0 [ 4.576698][ T6] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX [ 4.596268][ T1] Sending DHCP requests ., OK [ 5.580817][ T1] IP-Config: Got DHCP answer from 10.0.2.2, my address is 10.0.2.15 [ 5.581792][ T1] IP-Config: Complete: [ 5.582279][ T1] device=eth0, hwaddr=52:54:00:12:34:56, ipaddr=10.0.2.15, mask=255.255.255.0, gw=10.0.2.2 [ 5.583515][ T1] host=10.0.2.15, domain=, nis-domain=(none) [ 5.584311][ T1] bootserver=10.0.2.2, rootserver=10.0.2.2, rootpath= [ 5.584313][ T1] nameserver0=10.0.2.3 [ 5.585969][ T1] ALSA device list: [ 5.586415][ T1] #0: Dummy 1 [ 5.586818][ T1] #1: Loopback 1 [ 5.587279][ T1] #2: Virtual MIDI Card 1 [ 5.587839][ T1] #3: PCM-Test virtual driver [ 5.588620][ T1] #4: MTPAV on parallel port at 0x378 [ 5.591211][ T1] Freeing unused decrypted memory: 2036K [ 5.592786][ T1] Freeing unused kernel image (initmem) memory: 1712K [ 5.593380][ T1] Write protecting the kernel read-only data: 32768k [ 5.595203][ T1] Freeing unused kernel image (text/rodata gap) memory: 1400K [ 5.595969][ T1] Freeing unused kernel image (rodata/data gap) memory: 176K [ 5.597087][ T1] x86/mm: Checked W+X mappings: passed, no W+X pages found. [ 5.597704][ T1] Run /init as init process [ 5.598100][ T1] with arguments: [ 5.598430][ T1] /init [ 5.598702][ T1] with environment: [ 5.599058][ T1] HOME=/ [ 5.599349][ T1] TERM=linux [ 5.599662][ T1] RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 [ 5.601145][ T1] branch=linux-devel/devel-hourly-20251019-154855 [ 5.601729][ T1] job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml [ 5.603202][ T1] user=lkp [ 5.603493][ T1] ARCH=x86_64 [ 5.603823][ T1] kconfig=x86_64-randconfig-121-20251020 [ 5.604357][ T1] commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c [ 5.604957][ T1] intremap=posted_msi [ 5.605340][ T1] vmalloc=256M [ 5.605669][ T1] max_uptime=7200 [ 5.606031][ T1] LKP_LOCAL_RUN=1 [ 5.606374][ T1] selinux=0 [ 5.606686][ T1] prompt_ramdisk=0 [ 5.607036][ T1] vga=normal [ 5.607355][ T1] result_service=9p/virtfs_mount [ 5.607966][ T1] 32-bit emulation disabled. You can reenable with ia32_emulation=on [ 5.608710][ T1] Failed to execute /init (error -8) [ 5.609167][ T1] Run /sbin/init as init process [ 5.609590][ T1] with arguments: [ 5.609918][ T1] /sbin/init [ 5.610225][ T1] with environment: [ 5.610567][ T1] HOME=/ [ 5.610848][ T1] TERM=linux [ 5.611155][ T1] RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 [ 5.612624][ T1] branch=linux-devel/devel-hourly-20251019-154855 [ 5.613210][ T1] job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml [ 5.614672][ T1] user=lkp [ 5.614971][ T1] ARCH=x86_64 [ 5.615289][ T1] kconfig=x86_64-randconfig-121-20251020 [ 5.615802][ T1] commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c [ 5.616405][ T1] intremap=posted_msi [ 5.616769][ T1] vmalloc=256M [ 5.617094][ T1] max_uptime=7200 [ 5.617439][ T1] LKP_LOCAL_RUN=1 [ 5.617781][ T1] selinux=0 [ 5.618086][ T1] prompt_ramdisk=0 [ 5.618433][ T1] vga=normal [ 5.618749][ T1] result_service=9p/virtfs_mount [ 5.619299][ T1] Starting init: /sbin/init exists but couldn't execute it (error -8) [ 5.620023][ T1] Run /etc/init as init process [ 5.620470][ T1] with arguments: [ 5.620802][ T1] /etc/init [ 5.621108][ T1] with environment: [ 5.621445][ T1] HOME=/ [ 5.621730][ T1] TERM=linux [ 5.622050][ T1] RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 [ 5.623473][ T1] branch=linux-devel/devel-hourly-20251019-154855 [ 5.624069][ T1] job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml [ 5.625535][ T1] user=lkp [ 5.625819][ T1] ARCH=x86_64 [ 5.626136][ T1] kconfig=x86_64-randconfig-121-20251020 [ 5.626647][ T1] commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c [ 5.627222][ T1] intremap=posted_msi [ 5.627595][ T1] vmalloc=256M [ 5.627929][ T1] max_uptime=7200 [ 5.628299][ T1] LKP_LOCAL_RUN=1 [ 5.628643][ T1] selinux=0 [ 5.628943][ T1] prompt_ramdisk=0 [ 5.629291][ T1] vga=normal [ 5.629605][ T1] result_service=9p/virtfs_mount [ 5.630074][ T1] Starting init: /etc/init exists but couldn't execute it (error -13) [ 5.630768][ T1] Run /bin/init as init process [ 5.631183][ T1] with arguments: [ 5.631518][ T1] /bin/init [ 5.631824][ T1] with environment: [ 5.632178][ T1] HOME=/ [ 5.632472][ T1] TERM=linux [ 5.632786][ T1] RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 [ 5.634236][ T1] branch=linux-devel/devel-hourly-20251019-154855 [ 5.634816][ T1] job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml [ 5.636292][ T1] user=lkp [ 5.636582][ T1] ARCH=x86_64 [ 5.636901][ T1] kconfig=x86_64-randconfig-121-20251020 [ 5.637420][ T1] commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c [ 5.638008][ T1] intremap=posted_msi [ 5.638377][ T1] vmalloc=256M [ 5.638682][ T1] max_uptime=7200 [ 5.639039][ T1] LKP_LOCAL_RUN=1 [ 5.639383][ T1] selinux=0 [ 5.639682][ T1] prompt_ramdisk=0 [ 5.640039][ T1] vga=normal [ 5.640352][ T1] result_service=9p/virtfs_mount [ 5.640822][ T1] Run /bin/sh as init process [ 5.641222][ T1] with arguments: [ 5.641545][ T1] /bin/sh [ 5.641831][ T1] with environment: [ 5.642177][ T1] HOME=/ [ 5.642458][ T1] TERM=linux [ 5.642764][ T1] RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 [ 5.644180][ T1] branch=linux-devel/devel-hourly-20251019-154855 [ 5.644777][ T1] job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml [ 5.646205][ T1] user=lkp [ 5.646496][ T1] ARCH=x86_64 [ 5.646811][ T1] kconfig=x86_64-randconfig-121-20251020 [ 5.647318][ T1] commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c [ 5.647914][ T1] intremap=posted_msi [ 5.648300][ T1] vmalloc=256M [ 5.648620][ T1] max_uptime=7200 [ 5.648969][ T1] LKP_LOCAL_RUN=1 [ 5.649321][ T1] selinux=0 [ 5.649628][ T1] prompt_ramdisk=0 [ 5.649983][ T1] vga=normal [ 5.650291][ T1] result_service=9p/virtfs_mount [ 5.650807][ T1] Starting init: /bin/sh exists but couldn't execute it (error -8) [ 5.651481][ T1] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. [ 5.652784][ T1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc2-00182-gbab99e58f91f #35 PREEMPT [ 5.653668][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 5.654582][ T1] Call Trace: [ 5.654873][ T1] <TASK> [ 5.655137][ T1] dump_stack_lvl+0x3a/0x70 [ 5.655536][ T1] dump_stack+0x10/0x20 [ 5.655911][ T1] vpanic+0x104/0x2c0 [ 5.656256][ T1] ? rest_init+0x140/0x140 [ 5.656652][ T1] panic+0x51/0x60 [ 5.656989][ T1] kernel_init+0x111/0x120 [ 5.657360][ T1] ret_from_fork+0x25/0x140 [ 5.657741][ T1] ? rest_init+0x140/0x140 [ 5.658130][ T1] ret_from_fork_asm+0x11/0x20 [ 5.658563][ T1] </TASK> [ 5.658841][ T1] Kernel Offset: disabled ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-21 11:04 ` Peter Zijlstra @ 2025-10-27 12:54 ` Peter Zijlstra 2025-10-27 13:14 ` Chen, Yu C 0 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-10-27 12:54 UTC (permalink / raw) To: kernel test robot Cc: Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li, yu.c.chen On Tue, Oct 21, 2025 at 01:04:49PM +0200, Peter Zijlstra wrote: > On Tue, Oct 21, 2025 at 01:14:36PM +0800, kernel test robot wrote: > > > > > > Hello, > > > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on: > > > > commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield") > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core > > > > [test failed on linux-next/master 606da5bb165594c052ee11de79bf05bc38bc1aa6] > > > > in testcase: trinity > > version: > > with following parameters: > > > > runtime: 300s > > group: group-04 > > nr_groups: 5 > > > > > > > > config: x86_64-randconfig-121-20251020 > > compiler: gcc-13 > > test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > > > > > The kernel config and materials to reproduce are available at: > > https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com > > > I'm failing at running the kernel as described in: > > https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/reproduce > > > I then start the test as: > > root@spr:/usr/local/src/lkp-tests# bin/lkp qemu -k /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -m /usr/src/linux-2.6/tmp-build/modules.cgz /usr/src/linux-2.6/tmp-build/job-script > result_root: /root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4 > downloading initrds ... > use local modules: /root/.lkp/cache/modules.cgz > skip downloading /root/.lkp/cache/osimage/quantal/quantal-i386-core-20190426.cgz > 153636 blocks > skip downloading /root/.lkp/cache/osimage/pkg/quantal-i386-core.cgz/trinity-static-i386-x86_64-f93256fb_2019-08-28.cgz > 48101 blocks > exec command: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -fsdev local,id=test_dev,path=/root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4,security_model=none -device virtio-9p-pci,fsdev=test_dev,mount_tag=9p/virtfs_mount -kernel /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -append root=/dev/ram0 RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/vmlinuz-6.18.0-rc1-00001-g79104becf42b branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M initramfs_async=0 page_owner=on carrier_timeout=60 rcupdate.rcu_self_test=0 max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw ip=dhcp result_service=9p/virtfs_mount -initrd /root/.lkp/cache/final_initrd -smp 2 -m 16384M -no-reboot -device i6300esb -rtc base=localtime -device e1000,netdev=net0 -netdev user,id=net0 -display none -monitor null -serial stdio > [ 5.650807][ T1] Starting init: /bin/sh exists but couldn't execute it (error -8) > [ 5.651481][ T1] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. > [ 5.652784][ T1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc2-00182-gbab99e58f91f #35 PREEMPT > [ 5.653668][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 > [ 5.654582][ T1] Call Trace: > [ 5.654873][ T1] <TASK> > [ 5.655137][ T1] dump_stack_lvl+0x3a/0x70 > [ 5.655536][ T1] dump_stack+0x10/0x20 > [ 5.655911][ T1] vpanic+0x104/0x2c0 > [ 5.656256][ T1] ? rest_init+0x140/0x140 > [ 5.656652][ T1] panic+0x51/0x60 > [ 5.656989][ T1] kernel_init+0x111/0x120 > [ 5.657360][ T1] ret_from_fork+0x25/0x140 > [ 5.657741][ T1] ? rest_init+0x140/0x140 > [ 5.658130][ T1] ret_from_fork_asm+0x11/0x20 > [ 5.658563][ T1] </TASK> > [ 5.658841][ T1] Kernel Offset: disabled > Any clues how I can get this thing to actually run the trinity required to reproduce instead of panic? ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-27 12:54 ` Peter Zijlstra @ 2025-10-27 13:14 ` Chen, Yu C 2025-10-27 13:55 ` Peter Zijlstra 0 siblings, 1 reply; 26+ messages in thread From: Chen, Yu C @ 2025-10-27 13:14 UTC (permalink / raw) To: Peter Zijlstra, kernel test robot Cc: Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li, Sang, Oliver On 10/27/2025 8:54 PM, Peter Zijlstra wrote: > On Tue, Oct 21, 2025 at 01:04:49PM +0200, Peter Zijlstra wrote: >> On Tue, Oct 21, 2025 at 01:14:36PM +0800, kernel test robot wrote: >>> >>> >>> Hello, >>> >>> kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on: >>> >>> commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield") >>> https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core >>> >>> [test failed on linux-next/master 606da5bb165594c052ee11de79bf05bc38bc1aa6] >>> >>> in testcase: trinity >>> version: >>> with following parameters: >>> >>> runtime: 300s >>> group: group-04 >>> nr_groups: 5 >>> >>> >>> >>> config: x86_64-randconfig-121-20251020 >>> compiler: gcc-13 >>> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G >>> >> >>> The kernel config and materials to reproduce are available at: >>> https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com >> >> >> I'm failing at running the kernel as described in: >> >> https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/reproduce >> >> >> I then start the test as: >> >> root@spr:/usr/local/src/lkp-tests# bin/lkp qemu -k /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -m /usr/src/linux-2.6/tmp-build/modules.cgz /usr/src/linux-2.6/tmp-build/job-script >> result_root: /root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4 >> downloading initrds ... >> use local modules: /root/.lkp/cache/modules.cgz >> skip downloading /root/.lkp/cache/osimage/quantal/quantal-i386-core-20190426.cgz >> 153636 blocks >> skip downloading /root/.lkp/cache/osimage/pkg/quantal-i386-core.cgz/trinity-static-i386-x86_64-f93256fb_2019-08-28.cgz >> 48101 blocks >> exec command: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -fsdev local,id=test_dev,path=/root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4,security_model=none -device virtio-9p-pci,fsdev=test_dev,mount_tag=9p/virtfs_mount -kernel /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -append root=/dev/ram0 RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/vmlinuz-6.18.0-rc1-00001-g79104becf42b branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M initramfs_async=0 page_owner=on carrier_timeout=60 rcupdate.rcu_self_test=0 max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw ip=dhcp result_service=9p/virtfs_mount -initrd /root/.lkp/cache/final_initrd -smp 2 -m 16384M -no-reboot -device i6300esb -rtc base=localtime -device e1000,netdev=net0 -netdev user,id=net0 -display none -monitor null -serial stdio > >> [ 5.650807][ T1] Starting init: /bin/sh exists but couldn't execute it (error -8) May I know if you are using the kernel config 0day attached? I found that the config 0day attached (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) has CONFIG_IA32_EMULATION=y CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y CONFIG_COMPAT_32=y CONFIG_COMPAT=y It is suspected that the filesystem provided by lkp is 32bits, might need Oliver's confirm. thanks, Chenyu >> [ 5.651481][ T1] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. >> [ 5.652784][ T1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc2-00182-gbab99e58f91f #35 PREEMPT >> [ 5.653668][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 >> [ 5.654582][ T1] Call Trace: >> [ 5.654873][ T1] <TASK> >> [ 5.655137][ T1] dump_stack_lvl+0x3a/0x70 >> [ 5.655536][ T1] dump_stack+0x10/0x20 >> [ 5.655911][ T1] vpanic+0x104/0x2c0 >> [ 5.656256][ T1] ? rest_init+0x140/0x140 >> [ 5.656652][ T1] panic+0x51/0x60 >> [ 5.656989][ T1] kernel_init+0x111/0x120 >> [ 5.657360][ T1] ret_from_fork+0x25/0x140 >> [ 5.657741][ T1] ? rest_init+0x140/0x140 >> [ 5.658130][ T1] ret_from_fork_asm+0x11/0x20 >> [ 5.658563][ T1] </TASK> >> [ 5.658841][ T1] Kernel Offset: disabled >> > > Any clues how I can get this thing to actually run the trinity required > to reproduce instead of panic? ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-27 13:14 ` Chen, Yu C @ 2025-10-27 13:55 ` Peter Zijlstra 2025-10-27 14:07 ` Peter Zijlstra 0 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-10-27 13:55 UTC (permalink / raw) To: Chen, Yu C Cc: kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Mon, Oct 27, 2025 at 09:14:11PM +0800, Chen, Yu C wrote: > On 10/27/2025 8:54 PM, Peter Zijlstra wrote: > > On Tue, Oct 21, 2025 at 01:04:49PM +0200, Peter Zijlstra wrote: > > > On Tue, Oct 21, 2025 at 01:14:36PM +0800, kernel test robot wrote: > > > > > > > > > > > > Hello, > > > > > > > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on: > > > > > > > > commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield") > > > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core > > > > > > > > [test failed on linux-next/master 606da5bb165594c052ee11de79bf05bc38bc1aa6] > > > > > > > > in testcase: trinity > > > > version: > > > > with following parameters: > > > > > > > > runtime: 300s > > > > group: group-04 > > > > nr_groups: 5 > > > > > > > > > > > > > > > > config: x86_64-randconfig-121-20251020 > > > > compiler: gcc-13 > > > > test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > > > > > > > > > > > The kernel config and materials to reproduce are available at: > > > > https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com > > > > > > > > > I'm failing at running the kernel as described in: > > > > > > https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/reproduce > > > > > > > > > I then start the test as: > > > > > > root@spr:/usr/local/src/lkp-tests# bin/lkp qemu -k /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -m /usr/src/linux-2.6/tmp-build/modules.cgz /usr/src/linux-2.6/tmp-build/job-script > > > result_root: /root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4 > > > downloading initrds ... > > > use local modules: /root/.lkp/cache/modules.cgz > > > skip downloading /root/.lkp/cache/osimage/quantal/quantal-i386-core-20190426.cgz > > > 153636 blocks > > > skip downloading /root/.lkp/cache/osimage/pkg/quantal-i386-core.cgz/trinity-static-i386-x86_64-f93256fb_2019-08-28.cgz > > > 48101 blocks > > > exec command: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -fsdev local,id=test_dev,path=/root/.lkp//result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/4,security_model=none -device virtio-9p-pci,fsdev=test_dev,mount_tag=9p/virtfs_mount -kernel /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -append root=/dev/ram0 RESULT_ROOT=/result/trinity/group-04-5-300s/vm-snb/quantal-i386-core-20190426.cgz/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/1 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-121-20251020/gcc-13/79104becf42baeeb4a3f2b106f954b9fc7c10a3c/vmlinuz-6.18.0-rc1-00001-g79104becf42b branch=linux-devel/devel-hourly-20251019-154855 job=/lkp/jobs/scheduled/vm-meta-291/trinity-group-04-5-300s-quantal-i386-core-20190426.cgz-x86_64-randconfig-121-20251020-79104becf42b-20251020-124904-8548hu-1.yaml user=lkp ARCH=x86_64 kconfig=x86_64-randconfig-121-20251020 commit=79104becf42baeeb4a3f2b106f954b9fc7c10a3c intremap=posted_msi vmalloc=256M initramfs_async=0 page_owner=on carrier_timeout=60 rcupdate.rcu_self_test=0 max_uptime=7200 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw ip=dhcp result_service=9p/virtfs_mount -initrd /root/.lkp/cache/final_initrd -smp 2 -m 16384M -no-reboot -device i6300esb -rtc base=localtime -device e1000,netdev=net0 -netdev user,id=net0 -display none -monitor null -serial stdio > > > > > [ 5.650807][ T1] Starting init: /bin/sh exists but couldn't execute it (error -8) > > May I know if you are using the kernel config 0day attached? > I found that the config 0day attached > (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) > has > CONFIG_IA32_EMULATION=y > CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y > CONFIG_COMPAT_32=y > CONFIG_COMPAT=y > > It is suspected that the filesystem provided by lkp is 32bits, might > need Oliver's confirm. It was certainly meant to be that config -- let be double check that. ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-27 13:55 ` Peter Zijlstra @ 2025-10-27 14:07 ` Peter Zijlstra 2025-10-27 14:09 ` Peter Zijlstra 0 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-10-27 14:07 UTC (permalink / raw) To: Chen, Yu C Cc: kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Mon, Oct 27, 2025 at 02:55:16PM +0100, Peter Zijlstra wrote: > > May I know if you are using the kernel config 0day attached? > > I found that the config 0day attached > > (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) > > has > > CONFIG_IA32_EMULATION=y > > CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y Yep, deleting that entry makes it all work. You might want to fix the robot :-) > > CONFIG_COMPAT_32=y > > CONFIG_COMPAT=y > > > > It is suspected that the filesystem provided by lkp is 32bits, might > > need Oliver's confirm. > > It was certainly meant to be that config -- let be double check that. ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-27 14:07 ` Peter Zijlstra @ 2025-10-27 14:09 ` Peter Zijlstra 2025-10-28 2:30 ` Chen, Yu C 0 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-10-27 14:09 UTC (permalink / raw) To: Chen, Yu C Cc: kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Mon, Oct 27, 2025 at 03:07:18PM +0100, Peter Zijlstra wrote: > On Mon, Oct 27, 2025 at 02:55:16PM +0100, Peter Zijlstra wrote: > > > > May I know if you are using the kernel config 0day attached? > > > I found that the config 0day attached > > > (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) > > > has > > > CONFIG_IA32_EMULATION=y > > > CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y > > Yep, deleting that entry makes it all work. 'work' might be over stating, it boots and starts trinity, which then promptly (as in a handful of seconds) triggers OOM and dies. Not actually reproducing the NULL deref I was looking for. ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-27 14:09 ` Peter Zijlstra @ 2025-10-28 2:30 ` Chen, Yu C 2025-11-05 11:00 ` Peter Zijlstra 0 siblings, 1 reply; 26+ messages in thread From: Chen, Yu C @ 2025-10-28 2:30 UTC (permalink / raw) To: Peter Zijlstra Cc: kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On 10/27/2025 10:09 PM, Peter Zijlstra wrote: > On Mon, Oct 27, 2025 at 03:07:18PM +0100, Peter Zijlstra wrote: >> On Mon, Oct 27, 2025 at 02:55:16PM +0100, Peter Zijlstra wrote: >> >>>> May I know if you are using the kernel config 0day attached? >>>> I found that the config 0day attached >>>> (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) >>>> has >>>> CONFIG_IA32_EMULATION=y >>>> CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y >> >> Yep, deleting that entry makes it all work. > > 'work' might be over stating, it boots and starts trinity, which then > promptly (as in a handful of seconds) triggers OOM and dies. Not > actually reproducing the NULL deref I was looking for. Change the following line in job-script export memory='16G' to export memory='64G' ? I had a try and can reproduce the NULL except at first run: [ 137.151416][ T321] BUG: kernel NULL pointer dereference, address: 0000000000000051 [ 137.152128][ T321] #PF: supervisor read access in kernel mode [ 137.152661][ T321] #PF: error_code(0x0000) - not-present page [ 137.153155][ T321] PGD 100b76067 P4D 100b76067 PUD 115fd6067 PMD 0 [ 137.153834][ T321] Oops: Oops: 0000 [#1] [ 137.154256][ T321] CPU: 0 UID: 65534 PID: 321 Comm: trinity-c1 Not tainted 6.18.0-rc1-g30682ad76ee6 #4 PREEMPT [ 137.155384][ T321] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 137.156509][ T321] RIP: 0010:pick_task_fair+0x69/0x9d thanks, Chenyu ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-28 2:30 ` Chen, Yu C @ 2025-11-05 11:00 ` Peter Zijlstra 2025-11-05 12:06 ` Philip Li 0 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-11-05 11:00 UTC (permalink / raw) To: Chen, Yu C Cc: kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Tue, Oct 28, 2025 at 10:30:08AM +0800, Chen, Yu C wrote: > On 10/27/2025 10:09 PM, Peter Zijlstra wrote: > > On Mon, Oct 27, 2025 at 03:07:18PM +0100, Peter Zijlstra wrote: > > > On Mon, Oct 27, 2025 at 02:55:16PM +0100, Peter Zijlstra wrote: > > > > > > > > May I know if you are using the kernel config 0day attached? > > > > > I found that the config 0day attached > > > > > (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) > > > > > has > > > > > CONFIG_IA32_EMULATION=y > > > > > CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y > > > > > > Yep, deleting that entry makes it all work. > > > > 'work' might be over stating, it boots and starts trinity, which then > > promptly (as in a handful of seconds) triggers OOM and dies. Not > > actually reproducing the NULL deref I was looking for. > > Change the following line in job-script > export memory='16G' > to > export memory='64G' > ? Yes, that seems to help. > I had a try and can reproduce the NULL except at first run: Took me two runs, but yes, I can see it now. Anyway, this is two bugs in the robot, can we please fix all this to not happen again? - .config has 32bit disabled while robot provides 32bit images. Clearly the actual robot runs 64bit images and the reproduction should provide those too. - job description is inaccurate in the amount of memory required. The reproduction steps must exactly match what the real robot runs, not something else. ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-05 11:00 ` Peter Zijlstra @ 2025-11-05 12:06 ` Philip Li 2025-11-07 10:16 ` Philip Li 0 siblings, 1 reply; 26+ messages in thread From: Philip Li @ 2025-11-05 12:06 UTC (permalink / raw) To: Peter Zijlstra Cc: Chen, Yu C, kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Wed, Nov 05, 2025 at 12:00:26PM +0100, Peter Zijlstra wrote: > On Tue, Oct 28, 2025 at 10:30:08AM +0800, Chen, Yu C wrote: > > On 10/27/2025 10:09 PM, Peter Zijlstra wrote: > > > On Mon, Oct 27, 2025 at 03:07:18PM +0100, Peter Zijlstra wrote: > > > > On Mon, Oct 27, 2025 at 02:55:16PM +0100, Peter Zijlstra wrote: > > > > > > > > > > May I know if you are using the kernel config 0day attached? > > > > > > I found that the config 0day attached > > > > > > (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) > > > > > > has > > > > > > CONFIG_IA32_EMULATION=y > > > > > > CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y > > > > > > > > Yep, deleting that entry makes it all work. > > > > > > 'work' might be over stating, it boots and starts trinity, which then > > > promptly (as in a handful of seconds) triggers OOM and dies. Not > > > actually reproducing the NULL deref I was looking for. > > > > Change the following line in job-script > > export memory='16G' > > to > > export memory='64G' > > ? > > Yes, that seems to help. > > > I had a try and can reproduce the NULL except at first run: > > Took me two runs, but yes, I can see it now. > > Anyway, this is two bugs in the robot, can we please fix all this to not > happen again? Got it, I will dig into the detail to understand the difference of local reproduce and internal cluster run. The image, kconfig, and memory are exactly the same for actual robot run and provided reproduce instruction, since the attachment is reproduced from the job execution. I didn't find the cause quickly, and i will be back to this asap and provide update. > > - .config has 32bit disabled while robot provides 32bit images. Clearly > the actual robot runs 64bit images and the reproduction should > provide those too. > > - job description is inaccurate in the amount of memory required. > > The reproduction steps must exactly match what the real robot runs, not > something else. > ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-05 12:06 ` Philip Li @ 2025-11-07 10:16 ` Philip Li 2025-11-07 10:53 ` Peter Zijlstra 0 siblings, 1 reply; 26+ messages in thread From: Philip Li @ 2025-11-07 10:16 UTC (permalink / raw) To: Peter Zijlstra Cc: Chen, Yu C, kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Wed, Nov 05, 2025 at 08:06:32PM +0800, Philip Li wrote: > On Wed, Nov 05, 2025 at 12:00:26PM +0100, Peter Zijlstra wrote: > > On Tue, Oct 28, 2025 at 10:30:08AM +0800, Chen, Yu C wrote: > > > On 10/27/2025 10:09 PM, Peter Zijlstra wrote: > > > > On Mon, Oct 27, 2025 at 03:07:18PM +0100, Peter Zijlstra wrote: > > > > > On Mon, Oct 27, 2025 at 02:55:16PM +0100, Peter Zijlstra wrote: > > > > > > > > > > > > May I know if you are using the kernel config 0day attached? > > > > > > > I found that the config 0day attached > > > > > > > (https://download.01.org/0day-ci/archive/20251021/202510211205.1e0f5223-lkp@intel.com/config-6.18.0-rc1-00001-g79104becf42b) > > > > > > > has > > > > > > > CONFIG_IA32_EMULATION=y > > > > > > > CONFIG_IA32_EMULATION_DEFAULT_DISABLED=y > > > > > > > > > > Yep, deleting that entry makes it all work. > > > > > > > > 'work' might be over stating, it boots and starts trinity, which then > > > > promptly (as in a handful of seconds) triggers OOM and dies. Not > > > > actually reproducing the NULL deref I was looking for. > > > > > > Change the following line in job-script > > > export memory='16G' > > > to > > > export memory='64G' > > > ? > > > > Yes, that seems to help. > > > > > I had a try and can reproduce the NULL except at first run: > > > > Took me two runs, but yes, I can see it now. > > > > Anyway, this is two bugs in the robot, can we please fix all this to not > > happen again? > > Got it, I will dig into the detail to understand the difference of local > reproduce and internal cluster run. The image, kconfig, and memory > are exactly the same for actual robot run and provided reproduce instruction, > since the attachment is reproduced from the job execution. I didn't find the > cause quickly, and i will be back to this asap and provide update. > > > > > - .config has 32bit disabled while robot provides 32bit images. Clearly > > the actual robot runs 64bit images and the reproduction should > > provide those too. Some update that this one is resolved, the cluster run has set ia32_emulation=on in kernel cmdline, which is missed to set in the reproduce step. > > > > - job description is inaccurate in the amount of memory required. Got it, the cluster run with 16G has 40% rate (in about 20 runs), now i have increased the memory to 32G so it will reduce the OOM chance in local reproduction. > > > > The reproduction steps must exactly match what the real robot runs, not > > something else. Sorry for wrong reproduce steps, we should be more careful to make it consistent. And thanks again to Peter and Yu. > > ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-07 10:16 ` Philip Li @ 2025-11-07 10:53 ` Peter Zijlstra 0 siblings, 0 replies; 26+ messages in thread From: Peter Zijlstra @ 2025-11-07 10:53 UTC (permalink / raw) To: Philip Li Cc: Chen, Yu C, kernel test robot, Fernand Sieber, oe-lkp, lkp, linux-kernel, x86, aubrey.li On Fri, Nov 07, 2025 at 06:16:03PM +0800, Philip Li wrote: > Sorry for wrong reproduce steps, we should be more careful to make it consistent. No worries, shit happens. Thanks for getting it fixed! ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-10-21 5:14 [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address kernel test robot 2025-10-21 6:39 ` Chen, Yu C 2025-10-21 11:04 ` Peter Zijlstra @ 2025-11-04 21:04 ` Fernand Sieber 2025-11-05 8:43 ` Fernand Sieber ` (2 more replies) 2 siblings, 3 replies; 26+ messages in thread From: Fernand Sieber @ 2025-11-04 21:04 UTC (permalink / raw) To: kernel test robot Cc: oe-lkp, lkp, linux-kernel, x86, Peter Zijlstra, aubrey.li, yu.c.chen Hi Peter, I spent some time today investigating this report. The crash happens when a proxy task yields. Since it probably doesn't make sense that a task blocking the best pick yields, a simple workaround is to ignore the yield in this case: --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8993,6 +8993,11 @@ static void yield_task_fair(struct rq *rq) if (unlikely(rq->nr_running == 1)) return; + /* Don't yield if we're running a proxy task */ + if (rq->donor && rq->donor != curr) { + return; + } + However, more generally, I am not sure that the logic in update_min_vruntime() is sound when we are running a proxy task, which I suspect is the ultimate root cause of the problem. It seems to assume that cfs_rq->curr is the running task, which is not the case. In my troubleshooting I have seen inconsistent calculations with underflows of cfs_rq->avg_vruntime and avg_vruntime(cfs_rq) being lower than min_vruntime. I'll see if I can invest more time diving into this, in the meantime do you have any thoughts? Thanks, --Fernand Amazon Development Centre (South Africa) (Proprietary) Limited 29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa Registration Number: 2004 / 034463 / 07 ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-04 21:04 ` Fernand Sieber @ 2025-11-05 8:43 ` Fernand Sieber 2025-11-05 11:03 ` Peter Zijlstra 2025-11-05 12:28 ` Peter Zijlstra 2 siblings, 0 replies; 26+ messages in thread From: Fernand Sieber @ 2025-11-05 8:43 UTC (permalink / raw) To: kernel test robot Cc: oe-lkp, lkp, linux-kernel, x86, Peter Zijlstra, aubrey.li, yu.c.chen Hi Peter, I have done more code analysis and I think the following code is a better approach to handle proxy tasks: diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 00f9d6c05d4cf..65eb98a779f91 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8983,9 +8983,10 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev, struct t */ static void yield_task_fair(struct rq *rq) { - struct task_struct *curr = rq->curr; - struct cfs_rq *cfs_rq = task_cfs_rq(curr); - struct sched_entity *se = &curr->se; + struct task_struct *rq_curr = rq->curr; + struct cfs_rq *cfs_rq = task_cfs_rq(rq_curr); + struct sched_entity *se = &rq_curr->se; + bool curr = cfs_rq->curr == se; /* * Are we the only task in the tree? @@ -9016,8 +9017,12 @@ static void yield_task_fair(struct rq *rq) * ends up quickly running away. */ if (entity_eligible(cfs_rq, se)) { + if (!curr) + __dequeue_entity(cfs_rq, se); se->vruntime = se->deadline; se->deadline += calc_delta_fair(se->slice, se); + if (!curr) + __enqueue_entity(cfs_rq, se); update_min_vruntime(cfs_rq); } } I'll prepare rev4 of the patch accordingly. --Fernand Amazon Development Centre (South Africa) (Proprietary) Limited 29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa Registration Number: 2004 / 034463 / 07 ^ permalink raw reply related [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-04 21:04 ` Fernand Sieber 2025-11-05 8:43 ` Fernand Sieber @ 2025-11-05 11:03 ` Peter Zijlstra 2025-11-05 12:28 ` Peter Zijlstra 2 siblings, 0 replies; 26+ messages in thread From: Peter Zijlstra @ 2025-11-05 11:03 UTC (permalink / raw) To: Fernand Sieber Cc: kernel test robot, oe-lkp, lkp, linux-kernel, x86, aubrey.li, yu.c.chen On Tue, Nov 04, 2025 at 11:04:55PM +0200, Fernand Sieber wrote: > Hi Peter, > > I spent some time today investigating this report. The crash happens when > a proxy task yields. > Ooh, nice! ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-04 21:04 ` Fernand Sieber 2025-11-05 8:43 ` Fernand Sieber 2025-11-05 11:03 ` Peter Zijlstra @ 2025-11-05 12:28 ` Peter Zijlstra 2025-11-06 10:54 ` Fernand Sieber 2 siblings, 1 reply; 26+ messages in thread From: Peter Zijlstra @ 2025-11-05 12:28 UTC (permalink / raw) To: Fernand Sieber Cc: kernel test robot, oe-lkp, lkp, linux-kernel, x86, aubrey.li, yu.c.chen, jstultz On Tue, Nov 04, 2025 at 11:04:55PM +0200, Fernand Sieber wrote: > Hi Peter, > > I spent some time today investigating this report. The crash happens when > a proxy task yields. > > Since it probably doesn't make sense that a task blocking the best pick > yields, a simple workaround is to ignore the yield in this case: Well yield() as a whole doesn't make much sense outside of the strict RT setting where it is well defined. > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8993,6 +8993,11 @@ static void yield_task_fair(struct rq *rq) > if (unlikely(rq->nr_running == 1)) > return; > > + /* Don't yield if we're running a proxy task */ > + if (rq->donor && rq->donor != curr) { > + return; > + } Well, yield_task_fair() should probably have: struct task_struct curr = rq->donor; But yeah, if the task holding your resource is doing yield() you're 'sad'. Basically a sched-fair yield() means: I've no fucking clue what I'm doing and lets hope we can make progress a little later. And it gets worse in the context of PI/proxy, because in that case your fair task can deadlock the system through sheer incompetence. Anyway, consider the PI case, we bump a fair task to FIFO and then yield() would do the FIFO yield -- with all the possible problems. And we want the same for proxy, if the boosting context is FIFO, we want a FIFO yield. So I'm thinking, for all things to be consistent, we want something like: diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 6b8a9286e2fc..13112c680f92 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2143,7 +2143,7 @@ static void yield_task_dl(struct rq *rq) * it and the bandwidth timer will wake it up and will give it * new scheduling parameters (thanks to dl_yielded=1). */ - rq->curr->dl.dl_yielded = 1; + rq->donor->dl.dl_yielded = 1; update_rq_clock(rq); update_curr_dl(rq); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 273e2871b59e..f1d8eb350f59 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8980,7 +8980,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev, struct t */ static void yield_task_fair(struct rq *rq) { - struct task_struct *curr = rq->curr; + struct task_struct *curr = rq->donor; struct cfs_rq *cfs_rq = task_cfs_rq(curr); struct sched_entity *se = &curr->se; diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 1fd97f2d7ec6..f1867fe8e5c5 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1490,7 +1490,7 @@ static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head) static void yield_task_rt(struct rq *rq) { - requeue_task_rt(rq, rq->curr, 0); + requeue_task_rt(rq, rq->donor, 0); } static int find_lowest_rq(struct task_struct *task); diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c index 8f0f603b530b..865ec5d6e824 100644 --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -1319,7 +1319,7 @@ static void do_sched_yield(void) rq = this_rq_lock_irq(&rf); schedstat_inc(rq->yld_count); - current->sched_class->yield_task(rq); + rq->donor->sched_class->yield_task(rq); preempt_disable(); rq_unlock_irq(rq, &rf); ^ permalink raw reply related [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-05 12:28 ` Peter Zijlstra @ 2025-11-06 10:54 ` Fernand Sieber 2025-11-06 23:57 ` John Stultz 0 siblings, 1 reply; 26+ messages in thread From: Fernand Sieber @ 2025-11-06 10:54 UTC (permalink / raw) To: peterz Cc: aubrey.li, jstultz, linux-kernel, lkp, oe-lkp, oliver.sang, sieberf, x86, yu.c.chen Hi Peter, > But yeah, if the task holding your resource is doing yield() you're > 'sad'. Basically a sched-fair yield() means: I've no fucking clue what > I'm doing and lets hope we can make progress a little later. > > And it gets worse in the context of PI/proxy, because in that case your > fair task can deadlock the system through sheer incompetence. > > Anyway, consider the PI case, we bump a fair task to FIFO and then > yield() would do the FIFO yield -- with all the possible problems. > > And we want the same for proxy, if the boosting context is FIFO, we want > a FIFO yield. Alright, makes sense. Based on your suggestion I've submitted a patch: lore.kernel.org/lkml/20251106104022.195157-1-sieberf@amazon.com/T/#u This is essentially the same as your suggestion + handling of yield to and scx. Also confirmed no crashes with this patch + v3 of the vruntime forfeit patch https://lore.kernel.org/lkml/20250918150528.292620-1-sieberf@amazon.com/ --Fernand Amazon Development Centre (South Africa) (Proprietary) Limited 29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa Registration Number: 2004 / 034463 / 07 ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-06 10:54 ` Fernand Sieber @ 2025-11-06 23:57 ` John Stultz 2025-11-07 8:18 ` Fernand Sieber 0 siblings, 1 reply; 26+ messages in thread From: John Stultz @ 2025-11-06 23:57 UTC (permalink / raw) To: Fernand Sieber Cc: peterz, aubrey.li, linux-kernel, lkp, oe-lkp, oliver.sang, x86, yu.c.chen On Thu, Nov 6, 2025 at 2:54 AM Fernand Sieber <sieberf@amazon.com> wrote: > > But yeah, if the task holding your resource is doing yield() you're > > 'sad'. Basically a sched-fair yield() means: I've no fucking clue what > > I'm doing and lets hope we can make progress a little later. > > > > And it gets worse in the context of PI/proxy, because in that case your > > fair task can deadlock the system through sheer incompetence. > > > > Anyway, consider the PI case, we bump a fair task to FIFO and then > > yield() would do the FIFO yield -- with all the possible problems. > > > > And we want the same for proxy, if the boosting context is FIFO, we want > > a FIFO yield. > > Alright, makes sense. Based on your suggestion I've submitted a patch: > lore.kernel.org/lkml/20251106104022.195157-1-sieberf@amazon.com/T/#u > > This is essentially the same as your suggestion + handling of yield to and > scx. > > Also confirmed no crashes with this patch + v3 of the vruntime forfeit patch > https://lore.kernel.org/lkml/20250918150528.292620-1-sieberf@amazon.com/ > Fernand, Thank you so much for root causing this, and helping validate the fix works! I apologise for missing this case in my testing. I'll try to see if I can include the trinity test in my regular stress testing. Do let me know if you do see any other proxy related issues! thanks -john ^ permalink raw reply [flat|nested] 26+ messages in thread
* Re: [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address 2025-11-06 23:57 ` John Stultz @ 2025-11-07 8:18 ` Fernand Sieber 0 siblings, 0 replies; 26+ messages in thread From: Fernand Sieber @ 2025-11-07 8:18 UTC (permalink / raw) To: John Stultz Cc: peterz, aubrey.li, linux-kernel, lkp, oe-lkp, oliver.sang, x86, yu.c.chen On Thu, Nov 6, 2025 at 3:57 PM John Stultz <jstultz@google.com> wrote: > Fernand, Thank you so much for root causing this, and helping validate > the fix works! > I apologise for missing this case in my testing. I'll try to see if I > can include the trinity test in my regular stress testing. > > Do let me know if you do see any other proxy related issues! Hi John, No problem. I'm curious to understand more about the regular stress testing you are referring to, can you give me some pointers please? Thanks, Fernand Amazon Development Centre (South Africa) (Proprietary) Limited 29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa Registration Number: 2004 / 034463 / 07 ^ permalink raw reply [flat|nested] 26+ messages in thread
end of thread, other threads:[~2025-11-11 11:37 UTC | newest] Thread overview: 26+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-11-06 10:40 [PATCH] sched: Proxy yields to donor tasks Fernand Sieber 2025-11-06 10:57 ` Peter Zijlstra 2025-11-07 6:54 ` kernel test robot 2025-11-07 8:12 ` Fernand Sieber 2025-11-07 8:25 ` Peter Zijlstra 2025-11-11 11:37 ` [tip: sched/core] sched/proxy: Yield the donor task tip-bot2 for Fernand Sieber -- strict thread matches above, loose matches on Subject: below -- 2025-10-21 5:14 [tip:sched/core] [sched/fair] 79104becf4: BUG:kernel_NULL_pointer_dereference,address kernel test robot 2025-10-21 6:39 ` Chen, Yu C 2025-10-21 11:04 ` Peter Zijlstra 2025-10-27 12:54 ` Peter Zijlstra 2025-10-27 13:14 ` Chen, Yu C 2025-10-27 13:55 ` Peter Zijlstra 2025-10-27 14:07 ` Peter Zijlstra 2025-10-27 14:09 ` Peter Zijlstra 2025-10-28 2:30 ` Chen, Yu C 2025-11-05 11:00 ` Peter Zijlstra 2025-11-05 12:06 ` Philip Li 2025-11-07 10:16 ` Philip Li 2025-11-07 10:53 ` Peter Zijlstra 2025-11-04 21:04 ` Fernand Sieber 2025-11-05 8:43 ` Fernand Sieber 2025-11-05 11:03 ` Peter Zijlstra 2025-11-05 12:28 ` Peter Zijlstra 2025-11-06 10:54 ` Fernand Sieber 2025-11-06 23:57 ` John Stultz 2025-11-07 8:18 ` Fernand Sieber
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox