Patch "thermal: cpu_cooling: Avoid accessing potentially freed structures" has been added to the 4.12-stable tree

Patch "thermal: cpu_cooling: Avoid accessing potentially freed structures" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    thermal: cpu_cooling: Avoid accessing potentially freed structures

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     thermal-cpu_cooling-avoid-accessing-potentially-freed-structures.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 289d72afddf83440117c35d864bf0c6309c1d011 Mon Sep 17 00:00:00 2001
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: Tue, 25 Apr 2017 15:57:08 +0530
Subject: thermal: cpu_cooling: Avoid accessing potentially freed structures

From: Viresh Kumar <viresh.kumar@linaro.org>

commit 289d72afddf83440117c35d864bf0c6309c1d011 upstream.

After the lock is dropped, it is possible that the cpufreq_dev gets
freed before we call get_level() and that can cause kernel to crash.

Drop the lock after we are done using the structure.

Fixes: 02373d7c69b4 ("thermal: cpu_cooling: fix lockdep problems in cpu_cooling")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/thermal/cpu_cooling.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -153,8 +153,10 @@ unsigned long cpufreq_cooling_get_level(
 	mutex_lock(&cooling_list_lock);
 	list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) {
 		if (cpumask_test_cpu(cpu, &cpufreq_dev->allowed_cpus)) {
+			unsigned long level = get_level(cpufreq_dev, freq);
+
 			mutex_unlock(&cooling_list_lock);
-			return get_level(cpufreq_dev, freq);
+			return level;
 		}
 	}
 	mutex_unlock(&cooling_list_lock);


Patches currently in stable-queue which might be from viresh.kumar@linaro.org are

queue-4.12/thermal-cpu_cooling-avoid-accessing-potentially-freed-structures.patch