Messages in this thread Patch in this message | | | From | MyungJoo Ham <> | Subject | [PATCH] PM / devfreq: missing rcu_read_lock() added for find_device_opp() | Date | Wed, 21 Nov 2012 19:10:34 +0900 |
| |
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> --- drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++------ 1 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 45e053e..e91cb22 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -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); + if (!ret) + ret = srcu_notifier_chain_register(nh, &devfreq->nb); + rcu_read_unlock(); + + 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); + if (!ret) + ret = srcu_notifier_chain_unregister(nh, &devfreq->nb); + rcu_read_unlock(); + + return ret; } MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); -- 1.7.5.4
| |