Re: workqueue: WARN at at kernel/workqueue.c:2176

[Lai Jiangshan <laijs@cn.fujitsu.com>]

On 05/13/2014 04:01 AM, Tejun Heo wrote:
> On Mon, May 12, 2014 at 02:58:55PM -0400, Sasha Levin wrote:
>> Hi all,
>>
>> While fuzzing with trinity inside a KVM tools guest running the latest -next
>> kernel I've stumbled on the following spew:
>>
>> [ 1297.886670] WARNING: CPU: 0 PID: 190 at kernel/workqueue.c:2176 process_one_work+0xb5/0x6f0()
>> [ 1297.889216] Modules linked in:
>> [ 1297.890306] CPU: 0 PID: 190 Comm: kworker/3:0 Not tainted 3.15.0-rc5-next-20140512-sasha-00019-ga20bc00-dirty #456
>> [ 1297.893258]  0000000000000009 ffff88010c5d7ce8 ffffffffb153e1ec 0000000000000002
>> [ 1297.893258]  0000000000000000 ffff88010c5d7d28 ffffffffae15fd6c ffff88010cdd6c98
>> [ 1297.893258]  ffff8806285d4000 ffffffffb3cd09e0 ffff88010cdde000 0000000000000000
>> [ 1297.893258] Call Trace:
>> [ 1297.893258] dump_stack (lib/dump_stack.c:52)
>> [ 1297.893258] warn_slowpath_common (kernel/panic.c:430)
>> [ 1297.893258] warn_slowpath_null (kernel/panic.c:465)
>> [ 1297.893258] process_one_work (kernel/workqueue.c:2174 (discriminator 38))
>> [ 1297.893258] worker_thread (kernel/workqueue.c:2354)
>> [ 1297.893258] kthread (kernel/kthread.c:210)
>> [ 1297.893258] ret_from_fork (arch/x86/kernel/entry_64.S:553)

Hi,

I have been trying to address this bug.
Buy I can't reproduce this bug. Is your testing arch X86?
if yes, could you find out how to reproduce the bug?

Thanks,
Lai

> 
> Hmm, this is "percpu worker on the wrong CPU while the current
> workqueue state indicates it should be on the CPU it's bound to"
> warning.  We had a similar and more reproducible report a couple
> months back.
> 
>   http://lkml.kernel.org/g/52F4F01C.1070800@linux.vnet.ibm.com
> 
> We added some debug code back then and it looked like the worker was
> setting the right cpus_allowed mask and the cpu was up but still
> ending up on the wrong CPU.  Peter was looking into it and, ooh, I
> missed his last message and it fell through the crack.  We probably
> should follow up on that thread.
> 
> Thanks.
>