Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/urgent 07/10] cgroup: Check task_lock in task_subsys_state() | Date | Fri, 30 Apr 2010 17:26:11 -0700 |
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From: Li Zefan <lizf@cn.fujitsu.com>
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 <lizf@cn.fujitsu.com> Acked-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- include/linux/cgroup.h | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b8ad1ea..8f78073 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()); } -- 1.7.0
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