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Commit 5a7e56a5 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
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cpufreq: Initialize policy before making it available for others to use 



Policy must be fully initialized before it is being made available
for use by others. Otherwise cpufreq_cpu_get() would be able to grab
a half initialized policy structure that might not have affected_cpus
(for example) populated. Then, anybody accessing those fields will get
a wrong value and that will lead to unpredictable results.

In order to fix this, do all the necessary initialization before we
make the policy structure available via cpufreq_cpu_get(). That will
guarantee that any code accessing fields of the policy will get
correct data from them.

Reported-by: default avatarSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
[rjw: Changelog]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 999976e0

drivers/cpufreq/cpufreq.c

+14 −14
Original line number Diff line number Diff line
@@ -1109,6 +1109,20 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, 
		goto err_set_policy_cpu;

	}



	/* related cpus should atleast have policy->cpus */

	cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);



	/*

	 * affected cpus must always be the one, which are online. We aren't

	 * managing offline cpus here.

	 */

	cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);



	if (!frozen) {

		policy->user_policy.min = policy->min;

		policy->user_policy.max = policy->max;

	}



	write_lock_irqsave(&cpufreq_driver_lock, flags);

	for_each_cpu(j, policy->cpus)

		per_cpu(cpufreq_cpu_data, j) = policy;
@@ -1162,20 +1176,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, 
		}

	}



	/* related cpus should atleast have policy->cpus */

	cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);



	/*

	 * affected cpus must always be the one, which are online. We aren't

	 * managing offline cpus here.

	 */

	cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);



	if (!frozen) {

		policy->user_policy.min = policy->min;

		policy->user_policy.max = policy->max;

	}



	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,

				     CPUFREQ_START, policy);