The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fef05776eb02238dcad8d5514e666a42572c3f32 Mon Sep 17 00:00:00 2001

From: Lukasz Luba lukasz.luba@arm.com Date: Thu, 22 Apr 2021 16:36:22 +0100 Subject: [PATCH] thermal/core/fair share: Lock the thermal zone while looping over instances

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

diff --git a/drivers/thermal/gov_fair_share.c b/drivers/thermal/gov_fair_share.c index aaa07180ab48..645432ce6365 100644 --- a/drivers/thermal/gov_fair_share.c +++ b/drivers/thermal/gov_fair_share.c @@ -82,6 +82,8 @@ 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; @@ -110,6 +112,8 @@ 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; }