Re: workqueue lockup debug

[Thorsten Leemhuis]

On 24.10.24 17:49, John Garry wrote:
> Hi workqueue and scheduler maintainers,
> 
> As reported in https://lore.kernel.org/linux-fsdevel/df9db1ce-17d9-49f1-
> ab6d-7ed9a4f1f9c0@xxxxxxxxxx/T/
> #m506b9edb1340cdddd87c6d14d20222ca8d7e8796, I am experiencing a
> workqueue lockup for v6.12-rcX.

John, what this resolved in between? This and the other thread[1] look
stalled, but I might be missing something. Asking, because I have this
on my list of tracked regressions and wonder if this is something that
better should be solved one way or another before 6.12.

[1]
https://lore.kernel.org/lkml/63d6ceeb-a22f-4dee-bc9d-8687ce4c7355@xxxxxxxxxx/

Ciao, Thorsten

> At the point it occurs, the system becomes unresponsive and I cannot
> bring it back to life.
> 
> Enabling /proc/sys/kernel/softlockup_all_cpu_backtrace does not give
> anything extra in the way of debug. All I get is something like this:
> 
> Message from syslogd@jgarry-atomic-write-exp-e4-8-instance-20231214-1221
> at Oct 24 15:34:02 ...
>  kernel:watchdog: BUG: soft lockup - CPU#29 stuck for 22s! [mysqld:14352]
> 
> Message from syslogd@jgarry-atomic-write-exp-e4-8-instance-20231214-1221
> at Oct 24 15:34:02 ...
>  kernel:BUG: workqueue lockup - pool cpus=4 node=0 flags=0x0 nice=0
> stuck for 30s!
> 
> Message from syslogd@jgarry-atomic-write-exp-e4-8-instance-20231214-1221
> at Oct 24 15:34:02 ...
>  kernel:BUG: workqueue lockup - pool cpus=31 node=0 flags=0x0 nice=0
> stuck for 49s!
> ^C
> 
> Can you advise on a robust method to get some debug from this system?
> 
> Maybe this is a scheduler issue, as Dave mentioned in that same thread.
> 
> Thanks,
> John
> 

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