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 d3469fbc52072d755899e7e9b669f587f2e8af2e..26d7387f58349ab86d597ae45fc9b2da9a55ae0d 100644 (file)
--- a/drivers/thermal/fair_share.c
+++ b/drivers/thermal/fair_share.c
@@ -94,6 +94,8 @@ 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;
@@ -122,6 +124,8 @@ 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;
 }