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 4.9-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-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 289d72afddf83440117c35d864bf0c6309c1d011 Mon Sep 17 00:00:00 2001
From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Tue, 25 Apr 2017 15:57:08 +0530
Subject: thermal: cpu_cooling: Avoid accessing potentially freed structures
From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx>
Tested-by: Lukasz Luba <lukasz.luba@xxxxxxx>
Signed-off-by: Eduardo Valentin <edubezval@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -191,8 +191,10 @@ 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@xxxxxxxxxx are
queue-4.9/thermal-cpu_cooling-avoid-accessing-potentially-freed-structures.patch