linux-kernel - Re: [PATCH] cpufreq, store_scaling_governor requires policy->rwsem to be held for duration of changing governors [v2]

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Date:	Wed, 30 Jul 2014 18:36:00 -0700
From:	Saravana Kannan <skannan@...eaurora.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	Prarit Bhargava <prarit@...hat.com>, linux-kernel@...r.kernel.org,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Lenny Szubowicz <lszubowi@...hat.com>, linux-pm@...r.kernel.org
Subject: Re: [PATCH] cpufreq, store_scaling_governor requires policy->rwsem
 to be held for duration of changing governors [v2]

On 07/30/2014 02:40 PM, Rafael J. Wysocki wrote:
> On Wednesday, July 30, 2014 10:18:25 AM Prarit Bhargava wrote:
>>
>> On 07/29/2014 08:03 PM, Rafael J. Wysocki wrote:
>>> On Tuesday, July 29, 2014 07:46:02 AM Prarit Bhargava wrote:
>
> [cut]
>
>>>> This patch effectively reverts commit 955ef483.

The issue reported in this patch is valid. We are seeing that internally 
too. I believe I reported it in another thread (within the past month).

However, the original patch fixes a real deadlock issue (I'm too tired 
to look it up now). We can revet the original, but it's going to bring 
back the original issue. I just want to make sure Prarit and Raphael 
realize this before proceeding.

I do have plans for a proper fix for the mainline (not stable branches), 
but plan to do that after the current set of suspend/hotplug patches go 
through. The fix would be easier to make after that.

>>>
>>> OK, I'm convinced by this.
>>>
>>> I suppose we should push it for -stable from 3.10 through 3.15.x, right?
>>
>> Rafael, I think that is a good idea.  I'm not sure what the protocol is for
>> adding stable@...nel.org though ...
>
> I'll take care of this, thanks!
>

But you aren't going to pull the in for the next release, right?

-Saravana

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