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PM / devfreq: missing rcu_read_lock() added for find_device_opp() 

opp_get_notifier() uses find_device_opp(), which requires to
held rcu_read_lock. In order to keep the notifier-header
valid, we have added rcu_read_lock().

Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
This commit is contained in:
MyungJoo Ham 2012-11-21 19:04:51 +09:00
parent 883d588e55
commit 389baed01e
1 changed files with 20 additions and 6 deletions
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26
drivers/devfreq/devfreq.c
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@ -1023,11 +1023,18 @@ struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq,
*/
int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
{
struct srcu_notifier_head *nh = opp_get_notifier(dev);
struct srcu_notifier_head *nh;
int ret = 0;
rcu_read_lock();
nh = opp_get_notifier(dev);
if (IS_ERR(nh))
return PTR_ERR(nh);
return srcu_notifier_chain_register(nh, &devfreq->nb);
ret = PTR_ERR(nh);
rcu_read_unlock();
if (!ret)
ret = srcu_notifier_chain_register(nh, &devfreq->nb);
return ret;
}
/**
@ -1042,11 +1049,18 @@ int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
*/
int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
{
struct srcu_notifier_head *nh = opp_get_notifier(dev);
struct srcu_notifier_head *nh;
int ret = 0;
rcu_read_lock();
nh = opp_get_notifier(dev);
if (IS_ERR(nh))
return PTR_ERR(nh);
return srcu_notifier_chain_unregister(nh, &devfreq->nb);
ret = PTR_ERR(nh);
rcu_read_unlock();
if (!ret)
ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
return ret;
}
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");