From 1ce7e4ff24fe338438bc7837e02780f202bf202b Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 23 Apr 2010 10:35:52 +0800 Subject: cgroup: Check task_lock in task_subsys_state() Expand task_subsys_state()'s rcu_dereference_check() to include the full locking rule as documented in Documentation/cgroups/cgroups.txt by adding a check for task->alloc_lock being held. This fixes an RCU false positive when resuming from suspend. The warning comes from freezer cgroup in cgroup_freezing_or_frozen(). Signed-off-by: Li Zefan Acked-by: Matt Helsley Signed-off-by: Paul E. McKenney --- include/linux/cgroup.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b8ad1ea99586..8f78073d7caa 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -530,6 +530,7 @@ static inline struct cgroup_subsys_state *task_subsys_state( { return rcu_dereference_check(task->cgroups->subsys[subsys_id], rcu_read_lock_held() || + lockdep_is_held(&task->alloc_lock) || cgroup_lock_is_held()); } -- cgit v1.2.3