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cpufreq: Warn users while freeing active policy

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With the new design in place, the show() and store() callbacks check if
the policy is active or not before proceeding any further to avoid
potential races. And in order to guarantee that cpufreq_policy_free()
must be called after clearing the policy->cpus mask, i.e. by marking the
policy inactive.

In order to avoid introducing a bug around this later, print a warning
message if we end up freeing an active policy.

Also update cpufreq_online() a bit to make sure we clear the cpus mask
for each error case before calling cpufreq_policy_free().

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 2022-07-07 15:28:31 +05:30 committed by Rafael J. Wysocki
parent ca62229162
commit a2f6a7ac60
1 changed files with 8 additions and 2 deletions
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10
drivers/cpufreq/cpufreq.c
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@ -1273,6 +1273,13 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
unsigned long flags;
int cpu;
/*
* The callers must ensure the policy is inactive by now, to avoid any
* races with show()/store() callbacks.
*/
if (unlikely(!policy_is_inactive(policy)))
pr_warn("%s: Freeing active policy\n", __func__);
/* Remove policy from list */
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_del(&policy->policy_list);
@ -1527,8 +1534,6 @@ 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);
out_offline_policy:
if (cpufreq_driver->offline)
cpufreq_driver->offline(policy);
@ -1538,6 +1543,7 @@ static int cpufreq_online(unsigned int cpu)
cpufreq_driver->exit(policy);
out_free_policy:
cpumask_clear(policy->cpus);
up_write(&policy->rwsem);
cpufreq_policy_free(policy);