Andrei Vagin [off-list ref] wrote:

                ret = 0;
+               ctx->root = root;
                goto out_unlock;

Okay, I can see that.

                percpu_ref_reinit(&root->cgrp.self.refcnt);
                mutex_unlock(&cgroup_mutex);
        }
+       cgroup_get(&root->cgrp);

This probably needs to be conditional on ret == 0.

Which version are you testing btw?  The patches in git have been fixed a
little from what was last posted.

David