From 47560119ead39cfb8d684d5035a6c9b2663ad749 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@google.com>
Date: Wed, 21 Mar 2012 16:34:21 -0700
Subject: [PATCH] --- yaml --- r: 292682 b: refs/heads/master c:
 ca464d69b19120a826aa2534de2511a6f542edf5 h: refs/heads/master v: v3

---
 [refs]                | 2 +-
 trunk/kernel/cgroup.c | 5 ++---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index a478264abaa1..40d76811f144 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 42aee6c495e07dba7410b863a360db6bb9ec6d66
+refs/heads/master: ca464d69b19120a826aa2534de2511a6f542edf5
diff --git a/trunk/kernel/cgroup.c b/trunk/kernel/cgroup.c
index 8eb90f25bd7b..391d5e991e5f 100644
--- a/trunk/kernel/cgroup.c
+++ b/trunk/kernel/cgroup.c
@@ -5033,6 +5033,8 @@ css_get_next(struct cgroup_subsys *ss, int id,
 		return NULL;
 
 	BUG_ON(!ss->use_id);
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
 	/* fill start point for scan */
 	tmpid = id;
 	while (1) {
@@ -5040,10 +5042,7 @@ css_get_next(struct cgroup_subsys *ss, int id,
 		 * scan next entry from bitmap(tree), tmpid is updated after
 		 * idr_get_next().
 		 */
-		spin_lock(&ss->id_lock);
 		tmp = idr_get_next(&ss->idr, &tmpid);
-		spin_unlock(&ss->id_lock);
-
 		if (!tmp)
 			break;
 		if (tmp->depth >= depth && tmp->stack[depth] == rootid) {