Re: [mainline][BUG] Observed Workqueue lockups on offline CPUs.

[Samir M]

On 29/04/26 11:21 pm, Shrikanth Hegde wrote:
> Hi Samir.
>
> On 4/29/26 3:46 PM, Samir M wrote:
> > Hi Boqun,
> >
> > Thank you for pointing me to the existing patches. I have tested both 
> > Paul's patch [1] and TJ's workqueue patch [2] on my PowerPC system 
> > (80 CPUs), and can confirm that the workqueue lockup issue is not 
> > observed.
>
> Can you try only paul's patch and confirm if the issue is fixed?

Hi Shrikanth,

I have verified Paul’s “alone” patch, and it resolves the issue no 
workqueue lockups are observed.

Regards,
Samir.


> > Test Environment:
> > - System: PowerPC with 80 CPUs ( e.g. PowerPC LPARs with 80 online 
> > and 384 possible CPUs)
> > - Kernel version: Latest upstream (7.1-rc1)
> >
> > Regression Testing Results:
> > All tests completed successfully with no issues observed:
> > - Hackbench
> > - Kernel selftests
> > - LTP scheduler tests
> >
> > The workqueue lockup that was previously occurring is no longer 
> > present with the patches applied.
> >
> > References:
> > [1]: https://lore.kernel.org/rcu/ed1fa6cd-7343-4ca3-8b9d- 
> > d699ca496f83@paulmck-laptop/
> > [2]: https://lore.kernel.org/rcu/adlHKowvhn8AGXCc@xxxxxxxxxxxxxxx/
> >
> > Best regards,
> > Samir