Re: bpf selftests timer_lockup intermittently locks up kernel
"Kumar Kartikeya Dwivedi" <[email protected]>
| Newsgroups | dev.linux.lists.loongarch,org.kernel.vger.bpf |
|---|---|
| Message-ID | <[email protected]> |
On Mon Aug 17, 2026 at 6:04 AM CEST, Tiezhu Yang wrote:
> On 2025/8/25 上午2:26, Vincent Li wrote:
>> Hi,
>>
>> I am running bpf selftests on a Loonarch PC and observed intermittent
>> kernel lockup by timer_lockup, then I can repeat the lockup just by
>> running the timer_lockup in while loop every 5 seconds, I could not
>> find a good x86 machine to test, and I think this might be
>> architecture independent. I don't have a good way to capture any
>> kernel log messages for the PC after the kernel hangs, and I had to
>> power reset the PC.
>
> ...
>
>> #458 timer_lockup:FAIL
>> Caught signal #11!
>
> I recently spent some time investigating this and
> managed to reliably reproduce the issue.
>
> After adjusting some kernel configs and parameters,
> I successfully captured the call trace.
>
> The following patch fixes the issue, feel free to
> test it:
>
> LoongArch: Fix __smp_mb__{before,after}_atomic()
> https://lore.kernel.org/loongarch/[email protected]/
>
This looks correct to me. Also, nice that the test actually reproduces the issue
without that store-load barrier present, which is good validation for the kernel
side fix.