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>
Git-commit: 389baed01edd298c9622c6e28de5e7e250c8767d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Change-Id: I26a225ffa03003faa3f24822759548f6679ee591
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 4452249..f29d39d 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1023,11 +1023,18 @@
*/
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_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>");