cgroups: use hierarchy mutex in creation failure path

Now, cgrp->sibling is handled under hierarchy mutex.
error route should do so, too.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c298310..2ae7cb4 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2434,7 +2434,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 
  err_remove:
 
+       cgroup_lock_hierarchy(root);
        list_del(&cgrp->sibling);
+       cgroup_unlock_hierarchy(root);
        root->number_of_cgroups--;
 
  err_destroy: