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

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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: Schspa Shi <schspa@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Schspa Shi 2022-05-16 11:02:50 +08:00 committed by Rafael J. Wysocki
parent f339f35417
commit d4627a287e
1 changed files with 7 additions and 4 deletions
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11
drivers/cpufreq/cpufreq.c
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@ -948,13 +948,14 @@ 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);
ret = fattr->show(policy, buf);
if (likely(!policy_is_inactive(policy)))
ret = fattr->show(policy, buf);
up_read(&policy->rwsem);
return ret;
@ -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;
@ -979,7 +980,8 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
if (cpu_online(policy->cpu)) {
down_write(&policy->rwsem);
ret = fattr->store(policy, buf, count);
if (likely(!policy_is_inactive(policy)))
ret = fattr->store(policy, buf, count);
up_write(&policy->rwsem);
}
@ -1535,6 +1537,7 @@ out_destroy_policy:
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: