cpufreq: Make cpufreq_quick_get() safe to call
The function, cpufreq_quick_get, accesses the global 'cpufreq_driver' and its fields without taking the associated lock, cpufreq_driver_lock. Without the locking, nothing guarantees that 'cpufreq_driver' remains consistent during the call. This patch fixes the issue by taking the lock before accessing the data structure. Signed-off-by: Richard Cochran <rcochran@linutronix.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -1401,9 +1401,17 @@ unsigned int cpufreq_quick_get(unsigned int cpu)
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{
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struct cpufreq_policy *policy;
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unsigned int ret_freq = 0;
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unsigned long flags;
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if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
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return cpufreq_driver->get(cpu);
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read_lock_irqsave(&cpufreq_driver_lock, flags);
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if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
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ret_freq = cpufreq_driver->get(cpu);
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read_unlock_irqrestore(&cpufreq_driver_lock, flags);
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return ret_freq;
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}
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read_unlock_irqrestore(&cpufreq_driver_lock, flags);
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policy = cpufreq_cpu_get(cpu);
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if (policy) {
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