diff options
| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2025-07-09 20:27:52 +0900 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-07-09 13:40:17 +0200 |
| commit | 3da6bb419750f3ad834786d6ba7c9d5d062c770b (patch) | |
| tree | bae6e958112ec02dca0bc0ae0ddb66bffa70bd5d | |
| parent | d7b8f8e20813f0179d8ef519541a3527e7661d3a (diff) | |
perf/core: Fix WARN in perf_sigtrap()
Since exit_task_work() runs after perf_event_exit_task_context() updated
ctx->task to TASK_TOMBSTONE, perf_sigtrap() from perf_pending_task() might
observe event->ctx->task == TASK_TOMBSTONE.
Swap the early exit tests in order not to hit WARN_ON_ONCE().
Closes: https://syzkaller.appspot.com/bug?extid=2fe61cb2a86066be6985
Reported-by: syzbot <syzbot+2fe61cb2a86066be6985@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/b1c224bd-97f9-462c-a3e3-125d5e19c983@I-love.SAKURA.ne.jp
| -rw-r--r-- | kernel/events/core.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 0db36b2b2448..22fdf0c187cd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7204,18 +7204,18 @@ void perf_event_wakeup(struct perf_event *event) static void perf_sigtrap(struct perf_event *event) { /* - * We'd expect this to only occur if the irq_work is delayed and either - * ctx->task or current has changed in the meantime. This can be the - * case on architectures that do not implement arch_irq_work_raise(). + * Both perf_pending_task() and perf_pending_irq() can race with the + * task exiting. */ - if (WARN_ON_ONCE(event->ctx->task != current)) + if (current->flags & PF_EXITING) return; /* - * Both perf_pending_task() and perf_pending_irq() can race with the - * task exiting. + * We'd expect this to only occur if the irq_work is delayed and either + * ctx->task or current has changed in the meantime. This can be the + * case on architectures that do not implement arch_irq_work_raise(). */ - if (current->flags & PF_EXITING) + if (WARN_ON_ONCE(event->ctx->task != current)) return; send_sig_perf((void __user *)event->pending_addr, |