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thermal: cpu_cooling: Avoid accessing potentially freed structures

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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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Viresh Kumar 2017-04-25 15:57:08 +05:30 • committed by Greg Kroah-Hartman
parent f440ec864f
commit 2c1ac3721d
1 changed files with 3 additions and 1 deletions
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4
drivers/thermal/cpu_cooling.c
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@ -191,8 +191,10 @@ 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);