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Re: [RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in cpufreq_init_policy

From Viresh Kumar <viresh.kumar@linaro.org>
Newsgroups linux.kernel
Subject Re: [RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in cpufreq_init_policy
Date 2016-01-12 11:50 +0100
Message-ID <qQ4Gu-8a9-11@gated-at.bofh.it> (permalink)
References <qPOBH-5zs-9@gated-at.bofh.it> <qPOBK-5zs-47@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 11-01-16, 17:35, Juri Lelli wrote:
> There are paths in cpufreq_init_policy where policy is used, but its rwsem
> is not held.
> 
> Fix it.
> 
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
> ---
>  drivers/cpufreq/cpufreq.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index e7fc5c9..2c7cc6c73 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -998,21 +998,24 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp
>  {
>  	int ret = 0;
>  
> +	down_write(&policy->rwsem);
> +
>  	/* Has this CPU been taken care of already? */
> -	if (cpumask_test_cpu(cpu, policy->cpus))
> +	if (cpumask_test_cpu(cpu, policy->cpus)) {
> +		up_write(&policy->rwsem);

Perhaps create a label at the end to unlock the rwsem and jump to it?

-- 
viresh

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[RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in cpufreq_init_policy Juri Lelli <juri.lelli@arm.com> - 2016-01-11 18:40 +0100
  Re: [RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in  cpufreq_init_policy Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-12 11:50 +0100
    Re: [RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in  cpufreq_init_policy Juri Lelli <juri.lelli@arm.com> - 2016-01-14 19:00 +0100

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