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perf: Fix race between perf_event_exit_task() and perf_pending_task()

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A race condition exists between perf_event_exit_task() and
perf_pending_task() during begin_new_exec().

During begin_new_exec(), perf_event_exit_task() may be called, and the
PF_EXITING flag is not set on task. So perf_sigtrap() continues to execute
and triggers WARN_ON_ONCE(event->ctx->task != current).

Since both task exit and exec paths can call perf_event_exit_task() which
sets ctx->task to TASK_TOMBSTONE, fix this by explicitly checking if
event->ctx->task equals TASK_TOMBSTONE and dropping the redundant
PF_EXITING check.

Fixes: 97ba62b278 ("perf: Add support for SIGTRAP on perf events")
Signed-off-by: Luo Gengkun <luogengkun2@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260920075026.990582-1-luogengkun2@huawei.com
This commit is contained in:
Luo Gengkun 2026-09-20 07:50:26 +00:00 committed by Peter Zijlstra
parent 72d3fcf802
commit ffb684f2aa
1 changed files with 4 additions and 2 deletions
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6
kernel/events/core.c
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@ -7626,9 +7626,11 @@ static void perf_sigtrap(struct perf_event *event)
{
/*
* Both perf_pending_task() and perf_pending_irq() can race with the
* task exiting.
* task exiting or exec-ing. We can determine if such a race has
* occurred by checking if perf_event_exit_task(), which will set
* ctx->task to TASK_TOMBSTONE, has already been called.
*/
if (current->flags & PF_EXITING)
if (event->ctx->task == TASK_TOMBSTONE)
return;
/*