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

[Samir M <samir@linux.ibm.com>]

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@slm.duckdns.org/
>>
>> Best regards,
>> Samir
>