4.9-stable review patch. If anyone has any objections, please let me know.
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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);