diff options
| author | Viresh Kumar <viresh.kumar@linaro.org> | 2014-03-04 04:44:00 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-03-06 13:25:29 +0100 |
| commit | 5a7e56a5d29071bcccd947dee6e3b9f8e4eb3309 (patch) | |
| tree | 193f498e9337c598b56b00f1df8ee948a6184fe4 /drivers/cpufreq | |
| parent | cpufreq: use cpufreq_cpu_get() to avoid cpufreq_get() race conditions (diff) | |
| download | linux-5a7e56a5d29071bcccd947dee6e3b9f8e4eb3309.tar.xz linux-5a7e56a5d29071bcccd947dee6e3b9f8e4eb3309.zip | |
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>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index c4cacabbbb55..d6622689d000 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); |