Commit d4627a28 authored by Schspa Shi's avatar Schspa Shi Committed by Rafael J. Wysocki
Browse files

cpufreq: Abort show()/store() for half-initialized policies 



If policy initialization fails after the sysfs files are created,
there is a possibility to end up running show()/store() callbacks
for half-initialized policies, which may have unpredictable
outcomes.

Abort show()/store() in such a case by making sure the policy is active.

Also dectivate the policy on such failures.

Signed-off-by: default avatarSchspa Shi <schspa@gmail.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject and changelog edits ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f339f354

drivers/cpufreq/cpufreq.c

+7 −4
Original line number Diff line number Diff line
@@ -948,12 +948,13 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) 
{

	struct cpufreq_policy *policy = to_policy(kobj);

	struct freq_attr *fattr = to_attr(attr);

	ssize_t ret;

	ssize_t ret = -EBUSY;



	if (!fattr->show)

		return -EIO;



	down_read(&policy->rwsem);

	if (likely(!policy_is_inactive(policy)))

		ret = fattr->show(policy, buf);

	up_read(&policy->rwsem);
@@ -965,7 +966,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, 
{

	struct cpufreq_policy *policy = to_policy(kobj);

	struct freq_attr *fattr = to_attr(attr);

	ssize_t ret = -EINVAL;

	ssize_t ret = -EBUSY;



	if (!fattr->store)

		return -EIO;
@@ -979,6 +980,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, 


	if (cpu_online(policy->cpu)) {

		down_write(&policy->rwsem);

		if (likely(!policy_is_inactive(policy)))

			ret = fattr->store(policy, buf, count);

		up_write(&policy->rwsem);

	}
@@ -1535,6 +1537,7 @@ static int cpufreq_online(unsigned int cpu) 
	for_each_cpu(j, policy->real_cpus)

		remove_cpu_dev_symlink(policy, j, get_cpu_device(j));



	cpumask_clear(policy->cpus);

	up_write(&policy->rwsem);



out_offline_policy: