Subject: Re: [syzbot] [kernel?] linux-next test error: WARNING in class_for_each_device

From: "Danilo Krummrich" <[email-masked]>
Date: Tue, 26 May 2026 14:02:51 +0200

On Tue May 26, 2026 at 9:19 AM CEST, Tetsuo Handa wrote:
> On 2026/05/26 15:08, Tetsuo Handa wrote:
>> On 2026/05/26 14:55, syzbot wrote:
>>> Hello,
>>>
>>> syzbot found the following issue on:
>>>
>>> HEAD commit:    d387b06f7c15 Add linux-next specific files for 20260525
>>> git tree:       linux-next
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=15eb7796580000
>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=8dd72cf810e753a6
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=50b5f81fff158669504a
>>> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
>>>
>>> Downloadable assets:
>>> disk image: https://storage.googleapis.com/syzbot-assets/39490dfbc250/disk-d387b06f.raw.xz
>>> vmlinux: https://storage.googleapis.com/syzbot-assets/0789ac7ac5fc/vmlinux-d387b06f.xz
>>> kernel image: https://storage.googleapis.com/syzbot-assets/4464df9f5ccf/bzImage-d387b06f.xz
>>>
>>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>>> Reported-by: [email-masked]
>>>
>>> ------------[ cut here ]------------
>>> class_for_each_device called for class 'devlink' before it was registered
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/base?id=1137838865bfc9a7cd5869c1dc5c22aa45ec12c8
>> 
>> Why "driver_deferred_probe_timeout * HZ" => "driver_deferred_probe_timeout" ?
>> 
>
> Here is an analysis from Google AI mode regarding this problem: https://share.google/aimode/UO1WnoKPDSbyjY5Qj
>
> Greg, can you immediately drop commit 1137838865bf ("driver core: Use mod_delayed_work to prevent
> lost deferred probe work") so that syzbot can resume testing linux-next tree as soon as possible?

I already posted patches to fix this in [1]. I will pick them up today.

[1] https://lore.kernel.org/driver-core/[email-masked]/t/#u