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

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Date:	Sun, 04 Aug 2013 00:06:40 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Viresh Kumar <viresh.kumar@...aro.org>
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 Saturday, August 03, 2013 06:57:11 PM Viresh Kumar wrote:
> 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.

"it to be unloaded which may result in undefined behavior."

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

Apart from the above looks good.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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