linux-kernel - Re: [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's refcount

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Message-ID: <CAKohpokdWMjeZ=GKt4SaJDaA4Dn-WODpE_Mn+VEBpxB=VNAuyw@mail.gmail.com>
Date:	Sat, 3 Aug 2013 18:57:11 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, srivatsa.bhat@...ux.vnet.ibm.com,
	l.majewski@...sung.com
Subject: Re: [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's refcount

On 3 August 2013 17:38, Rafael J. Wysocki <rjw@...k.pl> wrote:
> On Saturday, August 03, 2013 05:19:26 PM Viresh Kumar wrote:
>> Governor's owner refcount usage was broken. We should increment refcount only
>> when CPUFREQ_GOV_POLICY_INIT event has come and should decrement only if
>> CPUFREQ_GOV_POLICY_EXIT has come.
>>
>> Lets fix it.
>
> OK, and what happens if we don't fix it?

What about this changelog:

Subject: [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's
 refcount

Governor's owner refcount usage was broken. We should increment refcount only
when CPUFREQ_GOV_POLICY_INIT event has come and should decrement only if
CPUFREQ_GOV_POLICY_EXIT has come.

Currently there can be situations where governor is in use but we have allowed
it to be unloaded. And that may cause in undefined behavior.

Lets fix it.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Download attachment "0008-cpufreq-Fix-broken-usage-of-governor-owner-s-refcoun.patch" of type "application/octet-stream" (2421 bytes)