thermal: lock the thermal zone when switching governors

Currently, userspace can request a governor change while the governor
itself is running.  Grab the thermal zone lock when changing the
governor to prevent this race.

Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 5aa57736fa9e..7b723c7c4cae 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -757,6 +757,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
         snprintf(name, sizeof(name), "%s", buf);
 
         mutex_lock(&thermal_governor_lock);
+        mutex_lock(&tz->lock);
 
         gov = __find_governor(strim(name));
         if (!gov)
@@ -766,6 +767,7 @@ policy_store(struct device *dev, struct device_attribute *attr,
         ret = count;
 
 exit:
+        mutex_unlock(&tz->lock);
         mutex_unlock(&thermal_governor_lock);
         return ret;
 }