cgroups: fix possible use after free
In cgroup_kill_sb(), root is freed before sb is detached from the list, so
another sget() may find this sb and call cgroup_test_super(), which will
access the root that has been freed.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: 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 e14db9c..9edb5c4 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1122,8 +1122,8 @@
mutex_unlock(&cgroup_mutex);
- kfree(root);
kill_litter_super(sb);
+ kfree(root);
}
static struct file_system_type cgroup_fs_type = {
