Re: [PATCH] perf: Ignore sigtrap for tracepoints destined for other tasks

From: Marco Elver
Date: Wed Nov 17 2021 - 09:07:23 EST

On Tue, 9 Nov 2021 at 13:22, Marco Elver <elver@xxxxxxxxxx> wrote:
> syzbot reported that the warning in perf_sigtrap() fires, saying that
> the event's task does not match current:
> | WARNING: CPU: 0 PID: 9090 at kernel/events/core.c:6446 perf_pending_event+0x40d/0x4b0 kernel/events/core.c:6513
> This happened because the 'sched_wakeup' tracepoint also takes a task
> argument passed on to perf_tp_event(), which is used to deliver the
> event to that other task.
> Since we cannot deliver synchronous signals to other tasks, skip an event if
> perf_tp_event() is targeted at another task and perf_event_attr::sigtrap is
> set, which will avoid ever entering perf_sigtrap() for such events.

Hmm, I made the mistake of sending this in the merge-window.
Any comments?

-- Marco