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

[James Clark <james.clark@linaro.org>]

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.