From: Viresh Kumar Date: Tue, 4 Mar 2014 03:44:00 +0000 (+0800) Subject: cpufreq: Initialize policy before making it available for others to use X-Git-Tag: v3.14-rc6~15^2^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5a7e56a5d29071bcccd947dee6e3b9f8e4eb3309;p=profile%2Fivi%2Fkernel-x86-ivi.git 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 Signed-off-by: Viresh Kumar [rjw: Changelog] Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index c4cacab..d6622689 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -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);