Re: CPU Lockups in KVM with deferred hrtimer rearming

Thomas Gleixner
2026-04-20T22:19:22Z

On Mon, Apr 20 2026 at 20:57, Verma, Vishal L wrote:
> On Mon, 2026-04-20 at 17:00 +0200, Thomas Gleixner wrote:
>>
>> This code should never be reached with a rearm pending. Something else
>> went wrong earlier. So while the patch "works" it papers over the
>> underlying problem.
>>
>> Can you please do the following:
>>
>>     1) Apply the patch below
>>
>>     2) Enable function tracing and the hrtimer* trace events
>>
>>     3) Enable tracing if it has been disabled already
>>
>>        echo 1 >/sys/kernel/tracing/tracing_on
>>
>>     4) Run the tests and wait for /sys/kernel/tracing/tracing_on to
>>        become 0, which means the problem triggered.
>>
>>     5) Retrieve the trace from /sys/kernel/tracing/trace and provide it
>>        somewhere to download from or send it to me compressed offlist.
>
> Hi Thomas,
>
> I've uploaded the trace here (~75MB compressed):
> https://drive.proton.me/urls/B9PY61XQ0C#07XwTVhE46eB
>
> As for:
>
> 1f5ffc672165 ("Fix mismerge of the arm64 / timer-core interrupt handling changes")
>
> I already had that commit in the branch that was tested and it didn't
> fix it.

Thanks for the update. Can you try to provide the information I asked
for above?

Thanks,

tglx