2 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 17604767adfd..f97522790682 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -270,6 +270,8 @@ enum {
          * - "release_agent" and "notify_on_release" are removed.
          *   Replacement notification mechanism will be implemented.
          *
+         * - rename(2) is disallowed.
+         *
          * - memcg: use_hierarchy is on by default and the cgroup file for
          *   the flag is not created.
          */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2e9da7bf25cb..c2c64005bbc2 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2508,6 +2508,13 @@ static int cgroup_rename(struct inode *old_dir, struct dentry *old_dentry,
 
         cgrp = __d_cgrp(old_dentry);
 
+        /*
+         * This isn't a proper migration and its usefulness is very
+         * limited.  Disallow if sane_behavior.
+         */
+        if (cgroup_sane_behavior(cgrp))
+                return -EPERM;
+
         name = cgroup_alloc_name(new_dentry);
         if (!name)
                 return -ENOMEM;