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cpufreq: Mark policy->governor = NULL for inactive policies 

Later commits would change the way policies are managed today. Policies
wouldn't be freed on cpu hotplug (currently they aren't freed on
suspend), and while the CPU is offline, the sysfs cpufreq files would
still be present.

Because we don't mark policy->governor as NULL, it still contains
pointer of the last used governor. And if the governor is removed, while
all the CPUs of a policy are hotplugged out, this pointer wouldn't be
valid anymore. And if we try to read the 'scaling_governor', etc.  from
sysfs, it will result in kernel OOPs.

To prevent this, mark policy->governor as NULL for all inactive policies
while the governor is removed from kernel.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2015-05-12 12:22:51 +05:30 committed by Rafael J. Wysocki
parent 4573237b01
commit 18bf3a124e
1 changed files with 3 additions and 2 deletions
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5
drivers/cpufreq/cpufreq.c
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@ -1083,7 +1083,6 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
if (likely(policy)) { if (likely(policy)) {
/* Policy should be inactive here */ /* Policy should be inactive here */
WARN_ON(!policy_is_inactive(policy)); WARN_ON(!policy_is_inactive(policy));
policy->governor = NULL;
} }
return policy; return policy;
@ -2145,9 +2144,11 @@ void cpufreq_unregister_governor(struct cpufreq_governor *governor)
/* clear last_governor for all inactive policies */ /* clear last_governor for all inactive policies */
read_lock_irqsave(&cpufreq_driver_lock, flags); read_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_inactive_policy(policy) { for_each_inactive_policy(policy) {
if (!strcmp(policy->last_governor, governor->name)) if (!strcmp(policy->last_governor, governor->name)) {
policy->governor = NULL;
strcpy(policy->last_governor, "\0"); strcpy(policy->last_governor, "\0");
} }
}
read_unlock_irqrestore(&cpufreq_driver_lock, flags); read_unlock_irqrestore(&cpufreq_driver_lock, flags);
mutex_lock(&cpufreq_governor_mutex); mutex_lock(&cpufreq_governor_mutex);