Re: [tip:perf/core] [perf] da916e96e2: BUG:KASAN:null-ptr-deref_in_put_event

[James Clark]

On 16/04/2025 8:08 pm, Peter Zijlstra wrote:
> On Wed, Apr 16, 2025 at 10:46:10AM +0200, Peter Zijlstra wrote:
> > On Tue, Apr 15, 2025 at 04:52:56PM +0100, James Clark wrote:
> > > Unrelated to the pointer deref issue, I'm also seeing perf stat not working
> > > due to this commit. And that's both with and without this fixup:
> > >
> > >   -> perf stat -- true
> > >
> > >   Performance counter stats for 'true':
> > >
> > >       <not counted> msec task-clock
> > >
> > >       <not counted>      context-switches
> > >
> > >       <not counted>      cpu-migrations
> > >
> > >       <not counted>      page-faults
> > >
> > >       <not counted>      armv8_cortex_a53/instructions/
> > >
> > >       <not counted>      armv8_cortex_a57/instructions/
> > >
> > >       <not counted>      armv8_cortex_a53/cycles/
> > >
> > >       <not counted>      armv8_cortex_a57/cycles/
> > >
> > >       <not counted>      armv8_cortex_a53/branches/
> > >
> > >       <not counted>      armv8_cortex_a53/branch-misses/
> > >
> > >       <not counted>      armv8_cortex_a57/branch-misses/
> > >
> > >
> > >         0.074139992 seconds time elapsed
> > >
> > >         0.000000000 seconds user
> > >         0.054797000 seconds sys
> > >
> > > Didn't look into it more other than bisecting it to this commit, but I can
> > > dig more unless the issue is obvious. This is on Arm big.LITTLE, although I
> > > didn't test it elsewhere so I'm not sure if that's relevant or not.
> >
> > I can reproduce on x86 alderlake (first machine I tried), so let me go
> > have a quick poke.
>
> Could you please try queue.git/perf/core ? I've fixed this and found
> another problem.
>
> I'll post the patches tomorrow, after the robot has had a go.

Yep that's all working now, thanks.