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

From: Viresh Kumar
Date: Tue Jan 12 2016 - 05:40:41 EST


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@xxxxxxxxxxxxx>
> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx>
> ---
> 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