+ cgroup-check-task_lock-in-task_subsys_state.patch added to -mm tree

+ cgroup-check-task_lock-in-task_subsys_state.patch added to -mm tree

[akpm]

The patch titled
     cgroup: check task_lock in task_subsys_state()
has been added to the -mm tree.  Its filename is
     cgroup-check-task_lock-in-task_subsys_state.patch

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------------------------------------------------------
Subject: cgroup: check task_lock in task_subsys_state()
From: Li Zefan <lizf@cn.fujitsu.com>

task_subsys_state() is safe under task_lock().  See
Documentation/cgroups/cgroups.txt for locking rule.

This fixes an RCU warning when resume 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>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cgroup.h |    1 +
 1 file changed, 1 insertion(+)

diff -puN include/linux/cgroup.h~cgroup-check-task_lock-in-task_subsys_state include/linux/cgroup.h
--- a/include/linux/cgroup.h~cgroup-check-task_lock-in-task_subsys_state
+++ a/include/linux/cgroup.h
@@ -530,6 +530,7 @@ static inline struct cgroup_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());
 }
 
_

Patches currently in -mm which might be from lizf@cn.fujitsu.com are

origin.patch
linux-next.patch
cgroup-check-task_lock-in-task_subsys_state.patch
memcg-rcu-lock-fix-v3.patch