Re: [PATCH] cpuidle: coupled: fix sleeping while atomic in cpu notifier

From: Colin Cross
Date: Thu Jul 26 2012 - 15:51:13 EST


On Thu, Jul 26, 2012 at 12:55 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> On Wednesday, July 25, 2012, Colin Cross wrote:
>> The cpu hotplug notifier gets called in both atomic and non-atomic
>> contexts, it is not always safe to lock a mutex. Filter out all events
>> except the six necessary ones, which are all sleepable, before taking
>> the mutex.
>
> I wonder what mutual exclusion mechanis we rely on when the mutex is not taken?

We don't need any mutual exclusion because the notifier returns immediately.
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