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

[Rafael J. Wysocki]

On Thursday, July 26, 2012, Colin Cross wrote:
> 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.

Don't we need to disable preemption even?
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