thermal/core/fair share: Lock the thermal zone while looping over instances

commit fef05776eb02238dcad8d5514e666a42572c3f32 upstream.

The tz->lock must be hold during the looping over the instances in that
thermal zone. This lock was missing in the governor code since the
beginning, so it's hard to point into a particular commit.

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210422153624.6074-2-lukasz.luba@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c
index 68bd1b56911850ee41dd7c508c7cad7f7c278ddf..da01b128c9a21ba4c44a3298ffb729d6dd461183 100644 (file)
--- a/drivers/thermal/fair_share.c
+++ b/drivers/thermal/fair_share.c
@@ -93,6 +93,8 @@ static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
        int total_instance = 0;
        int cur_trip_level = get_trip_level(tz);
 
+       mutex_lock(&tz->lock);
+
        list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
                if (instance->trip != trip)
                        continue;
@@ -121,6 +123,8 @@ static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
                mutex_unlock(&instance->cdev->lock);
                thermal_cdev_update(cdev);
        }
+
+       mutex_unlock(&tz->lock);
        return 0;
 }