From: "Kumar Kartikeya Dwivedi" <memxor@gmail.com>
To: "Tiezhu Yang" <yangtiezhu@loongson.cn>,
"Vincent Li" <vincent.mc.li@gmail.com>,
"bpf" <bpf@vger.kernel.org>
Cc: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
<loongarch@lists.linux.dev>
Subject: Re: bpf selftests timer_lockup intermittently locks up kernel
Date: Mon, 17 Aug 2026 06:38:45 +0200 [thread overview]
Message-ID: <DKQXWK0ILLSS.UF4CVFD9NO3I@gmail.com> (raw)
In-Reply-To: <d06a7557-fb51-2be9-63cd-3269533476b2@loongson.cn>
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/20260817035908.460-1-yangtiezhu@loongson.cn/
>
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.
prev parent reply other threads:[~2026-08-17 4:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-24 18:26 bpf selftests timer_lockup intermittently locks up kernel Vincent Li
2026-08-17 4:04 ` Tiezhu Yang
2026-08-17 4:38 ` Kumar Kartikeya Dwivedi [this message]
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