FAILED: patch "[PATCH] thermal/core/fair share: Lock the thermal zone while looping" failed to apply to 4.19-stable tree

FAILED: patch "[PATCH] thermal/core/fair share: Lock the thermal zone while looping" failed to apply to 4.19-stable tree

[gregkh]

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;
 }