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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-30 02:45:07 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-31 23:01:19 +0300
commitfdd320da84c63092fe6e155cb7b8d80f7f765fa9 (patch)
tree43945999294bf7359160ef43faefcda25186ffe0 /drivers/cpufreq
parent194d99c7e3ce54a8c7d8adf79fb1d8ad49a9bf9f (diff)
downloadlinux-fdd320da84c63092fe6e155cb7b8d80f7f765fa9.tar.xz
cpufreq: Lock CPU online/offline in cpufreq_register_driver()
To protect against races with concurrent CPU online/offline, call get_online_cpus() before registering a cpufreq driver. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 24e4ba568e77..0f4e96ff99e8 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2471,10 +2471,14 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
pr_debug("trying to register driver %s\n", driver_data->name);
+ /* Protect against concurrent CPU online/offline. */
+ get_online_cpus();
+
write_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return -EEXIST;
+ ret = -EEXIST;
+ goto out;
}
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -2513,7 +2517,10 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
register_hotcpu_notifier(&cpufreq_cpu_notifier);
pr_debug("driver %s up and running\n", driver_data->name);
- return 0;
+out:
+ put_online_cpus();
+ return ret;
+
err_if_unreg:
subsys_interface_unregister(&cpufreq_interface);
err_boost_unreg:
@@ -2523,7 +2530,7 @@ err_null_driver:
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return ret;
+ goto out;
}
EXPORT_SYMBOL_GPL(cpufreq_register_driver);