Re: [PATCH] perf: Fix missing SIGTRAPs

[Marco Elver]

On Fri, Oct 07, 2022 at 06:14PM +0200, Marco Elver wrote:
> On Fri, Oct 07, 2022 at 03:58PM +0200, Marco Elver wrote:
> > On Fri, Oct 07, 2022 at 03:09PM +0200, Peter Zijlstra wrote:
> > > On Fri, Oct 07, 2022 at 11:37:34AM +0200, Marco Elver wrote:
> > > 
> > > > That worked. In addition I had to disable the ctx->task != current check
> > > > if we're in task_work, because presumably the event might have already
> > > > been disabled/moved??
> > > 
> > > Uhmmm... uhhh... damn. (wall-time was significantly longer)
> > > 
> > > Does this help?
> > 
> > No unfortunately - still see:
> > 
> > [   82.300827] ------------[ cut here ]------------
> > [   82.301680] WARNING: CPU: 0 PID: 976 at kernel/events/core.c:6466 perf_sigtrap+0x60/0x70
> 
> Whenever the warning fires, I see that event->state is OFF.

The below patch to the sigtrap_threads test can repro the issue (when
run lots of them concurrently again). It also illustrates the original
problem we're trying to solve, where the event never gets rearmed again
and the test times out (doesn't happen with the almost-working fix).

Thanks,
-- Marco

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