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

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Date:	Fri, 27 Jul 2012 00:54:39 +0200
From:	"Shilimkar, Santosh" <santosh.shilimkar@...com>
To:	linux-kernel@...r.kernel.org
Cc:	Len Brown <lenb@...nel.org>, Len Brown <len.brown@...el.com>,
	Kevin Hilman <khilman@...com>,
	"Rafael J. Wysocki" <rjw@...k.pl>, Colin Cross <ccross@...roid.com>
Subject: Re: [PATCH] cpuidle: coupled: fix sleeping while atomic in cpu notifier

On Thu, Jul 26, 2012 at 9:25 AM, Shilimkar, Santosh
<santosh.shilimkar@...com> wrote:
> On Wed, Jul 25, 2012 at 11:20 PM, Colin Cross <ccross@...roid.com> 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.
>>
>> Signed-off-by: Colin Cross <ccross@...roid.com>
>> ---
> Agree.
> Have you observed any lock-up ?
>
Colin explained me about cause of the issue in an off-list discussion.
Thought of updating the thread in case some one wants to reproduce the
issue. You get  a warning during cpu hotplug in suspend if you turn on
sleeping while atomic debugging option in kernel build and the patch
fixes it.

Regards
Santosh
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