Re: [v3.10 regression] deadlock on cpu hotplug

From: Michael Wang
Date: Wed Jul 10 2013 - 02:05:12 EST


On 07/10/2013 01:39 PM, Viresh Kumar wrote:
> On 10 July 2013 09:42, Michael Wang <wangyun@xxxxxxxxxxxxxxxxxx> wrote:
>> I'm not sure what is supposed after notify CPUFREQ_GOV_STOP event, if it
>> is in order to stop queued work and prevent follow work happen again,
>> then it failed to, and we need some method to stop queue work again when
>> CPUFREQ_GOV_STOP notified, like some flag in policy which will be
>> checked before re-queue work in work.
>>
>> But if the event is just to sync the queued work but not prevent follow
>> work happen, then things will become tough...we need confirm.
>
> After GOV_STOP, until the time GOV_START is called, we shouldn't be
> queuing any work.

Thanks for the confirm :) seems like the root cause is very likely
related with the problem Srivatsa discovered.

I think the fix in his mail worth a try, but I need more investigations
to confirm that's the right way...

Regards,
Michael Wang

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