Re: [PATCH] perf/core: Fix race between perf_event_exit_task and perf_pending_task

[Ian Rogers]

On Wed, Apr 15, 2026 at 8:08 PM Luo Gengkun <luogengkun2@xxxxxxxxxx> wrote:
>
> A race condition exists between perf_event_exit_task() and perf_pending_task().
>
> 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).
>
> To fix this problem, also check if the event->ctx->task is TASK_TOMBSTONE.
>
> Fixes: 97ba62b27867 ("perf: Add support for SIGTRAP on perf events")
> Signed-off-by: Luo Gengkun <luogengkun2@xxxxxxxxxx>

Dmitry, the description and patch look sensible. Could you take a look?

Thanks,
Ian

> ---
>  kernel/events/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 1f5699b339ec..3422900263fa 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7543,7 +7543,7 @@ static void perf_sigtrap(struct perf_event *event)
>          * Both perf_pending_task() and perf_pending_irq() can race with the
>          * task exiting.
>          */
> -       if (current->flags & PF_EXITING)
> +       if (current->flags & PF_EXITING || event->ctx->task == TASK_TOMBSTONE)
>                 return;
>
>         /*
> --
> 2.34.1
>