From: Dave Chinner <david@fromorbit.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [6.13-rc0 regression] workqueue throwing cpu affinity warnings during CPU hotplug
Date: Thu, 12 Dec 2024 10:11:12 +1100 [thread overview]
Message-ID: <Z1ocEDhfwJ0Q-WYm@dread.disaster.area> (raw)
In-Reply-To: <Z1oY1qk-eWU8IcH3@slm.duckdns.org>
On Wed, Dec 11, 2024 at 12:57:26PM -1000, Tejun Heo wrote:
> Hello, Dave.
>
> Sorry about the really late reply.
>
> On Fri, Nov 22, 2024 at 11:38:19AM +1100, Dave Chinner wrote:
> > Hi Tejun,
> >
> > I just upgraded my test VMs from 6.12.0 to a current TOT kernel and
> > I got several of these warnings whilst running fstests whilst
> > running CPU hotplug online/offline concurrently with various tests:
> >
> > [ 2508.109594] ------------[ cut here ]------------
> > [ 2508.115669] WARNING: CPU: 23 PID: 133 at kernel/kthread.c:76 kthread_set_per_cpu+0x33/0x50
> ...
> > [ 2508.253909] <TASK>
> > [ 2508.311972] unbind_worker+0x1b/0x70
> > [ 2508.315444] workqueue_offline_cpu+0xd8/0x1f0
> > [ 2508.319554] cpuhp_invoke_callback+0x13e/0x4f0
> > [ 2508.328936] cpuhp_thread_fun+0xda/0x120
> > [ 2508.332746] smpboot_thread_fn+0x132/0x1d0
> > [ 2508.336645] kthread+0x147/0x170
> > [ 2508.347646] ret_from_fork+0x3e/0x50
> > [ 2508.353845] ret_from_fork_asm+0x1a/0x30
> > [ 2508.357773] </TASK>
> > [ 2508.357776] ---[ end trace 0000000000000000 ]---
>
> So, this is kthread saying that the thread passed to it doesn't have
> PF_KTHREAD set. There hasn't been any related changes and the flag is never
> cleared once set, so I don't see how that could be for a kworker.
....
> > I didn't see these on 6.12.0, so I'm guessing that there is
> > something in the merge window that has started triggering this.
>
> I tried a few mixtures of stress-ng + continuous hot [un]plugging but can't
> reproduce in the current linus#master. Do you still see this happening?
I don't know. The machine that I was using to reproduce this has
been down with hardware failure for the last two weeks. I might have
it back up today, and then I'll be able to start exercising this
again.
-Dave.
--
Dave Chinner
david@fromorbit.com
prev parent reply other threads:[~2024-12-11 23:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-22 0:38 [6.13-rc0 regression] workqueue throwing cpu affinity warnings during CPU hotplug Dave Chinner
2024-12-11 22:57 ` Tejun Heo
2024-12-11 23:11 ` Dave Chinner [this message]
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