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.
Cc: 4.2+ stable@vger.kernel.org # 4.2+ Fixes: 02373d7c69b4 ("thermal: cpu_cooling: fix lockdep problems in cpu_cooling") Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Tested-by: Lukasz Luba lukasz.luba@arm.com --- drivers/thermal/cpu_cooling.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c index 69d0f430b2d1..be29489dd247 100644 --- a/drivers/thermal/cpu_cooling.c +++ b/drivers/thermal/cpu_cooling.c @@ -153,8 +153,10 @@ unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq) 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);