Re: hit a KASan bug related to Perf during stress test

Peter Zijlstra
2016-10-24T11:27:36Z

On Mon, Oct 24, 2016 at 01:15:27PM +0200, Oleg Nesterov wrote:
> How about the trivial fix below?
>
> Oleg.
>
> --- x/kernel/events/core.c
> +++ x/kernel/events/core.c
> @@ -1257,7 +1257,7 @@ static u32 perf_event_pid(struct perf_ev
> if (event->parent)
> event = event->parent;
>
> - return task_tgid_nr_ns(p, event->ns);
> + return pid_alive(p) ? task_tgid_nr_ns(p, event->ns) : 0;
> }

Also, now we get a (few) sample(s) with a different pid:tid than prior
samples and not matching the sched_switch() events.

I can imagine that being somewhat confusing for people/tools.

Acme/Jolsa, any idea if that will bugger perf-report?