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: Saravana Kannan <skannan@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [rjw: Changelog] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -1109,6 +1109,20 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
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goto err_set_policy_cpu;
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}
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/* related cpus should atleast have policy->cpus */
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cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
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/*
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* affected cpus must always be the one, which are online. We aren't
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* managing offline cpus here.
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*/
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cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
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if (!frozen) {
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policy->user_policy.min = policy->min;
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policy->user_policy.max = policy->max;
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}
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write_lock_irqsave(&cpufreq_driver_lock, flags);
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for_each_cpu(j, policy->cpus)
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per_cpu(cpufreq_cpu_data, j) = policy;
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@ -1162,20 +1176,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
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}
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}
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/* related cpus should atleast have policy->cpus */
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cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
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/*
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* affected cpus must always be the one, which are online. We aren't
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* managing offline cpus here.
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*/
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cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
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if (!frozen) {
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policy->user_policy.min = policy->min;
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policy->user_policy.max = policy->max;
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}
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blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
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CPUFREQ_START, policy);
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