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thermal: cpu_cooling: Avoid accessing potentially freed structures 

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: 02373d7c69 ("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>
hifive-unleashed-5.1
Viresh Kumar 2017-04-25 15:57:08 +05:30 committed by Eduardo Valentin
parent 2ea659a9ef
commit 289d72afdd
1 changed files with 3 additions and 1 deletions
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4
drivers/thermal/cpu_cooling.c
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@ -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);