4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tejun Heo <t...@kernel.org>
commit 8fa3b8d689a54d6d04ff7803c724fb7aca6ce98e upstream.
If percpu_ref initialization fails during css_create(), the free path
can end up trying to free css->id of zero. As ID 0 is unused, it
doesn't cause a critical breakage but it does trigger a warning
message. Fix it by setting css->id to -1 from init_and_link_css().
Signed-off-by: Tejun Heo <t...@kernel.org>
Cc: Wenwei Tao <ww.tao0...@gmail.com>
Fixes: 01e586598b22 ("cgroup: release css->id after css_free")
Signed-off-by: Tejun Heo <t...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
kernel/cgroup.c | 1 +
1 file changed, 1 insertion(+)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4793,6 +4793,7 @@ static void init_and_link_css(struct cgr
memset(css, 0, sizeof(*css));
css->cgroup = cgrp;
css->ss = ss;
+ css->id = -1;
INIT_LIST_HEAD(&css->sibling);
INIT_LIST_HEAD(&css->children);
css->serial_nr = css_serial_nr_next++;
