diff options
| author |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-07-30 01:45:07 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-07-31 22:01:19 +0200 |
| commit | fdd320da84c63092fe6e155cb7b8d80f7f765fa9 (patch) | |
| tree | 43945999294bf7359160ef43faefcda25186ffe0 /drivers/cpufreq | |
| parent | cpufreq: Replace recover_policy with new_policy in cpufreq_online() (diff) | |
| download | linux-dev-fdd320da84c63092fe6e155cb7b8d80f7f765fa9.tar.xz linux-dev-fdd320da84c63092fe6e155cb7b8d80f7f765fa9.zip | |
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.c | 13 |
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); |