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[V3,06/14] cpufreq: Mark policy->governor = NULL for inactive policies

Message ID 58eb9c886496ba58c3fbdf5afb261ed89b157d0e.1431065963.git.viresh.kumar@linaro.org
State New
Headers show

Commit Message

Viresh Kumar May 8, 2015, 6:23 a.m. UTC
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>
---
 drivers/cpufreq/cpufreq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 5e87679ec6d1..bd8a47b5054e 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1095,7 +1095,6 @@  static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
 	if (likely(policy)) {
 		/* Policy should be inactive here */
 		WARN_ON(!policy_is_inactive(policy));
-		policy->governor = NULL;
 	}
 
 	return policy;
@@ -2157,8 +2156,10 @@  void cpufreq_unregister_governor(struct cpufreq_governor *governor)
 	/* clear last_governor for all inactive policies */
 	read_lock_irqsave(&cpufreq_driver_lock, flags);
 	for_each_inactive_policy(policy, tpolicy) {
-		if (!strcmp(policy->last_governor, governor->name))
+		if (!strcmp(policy->last_governor, governor->name)) {
+			policy->governor = NULL;
 			strcpy(policy->last_governor, "\0");
+		}
 	}
 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);