From: Li Zefan <lizefan@huawei.com>
Date: Mon, 18 Feb 2013 06:13:35 +0000 (+0800)
Subject: cgroup: fail if monitored file and event_control are in different cgroup
X-Git-Tag: v3.2.52~20
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31e0470e9906c42edfc4cf00404d4eb3a99dac7e;p=pandora-kernel.git

cgroup: fail if monitored file and event_control are in different cgroup

commit f169007b2773f285e098cb84c74aac0154d65ff7 upstream.

If we pass fd of memory.usage_in_bytes of cgroup A to cgroup.event_control
of cgroup B, then we won't get memory usage notification from A but B!

What's worse, if A and B are in different mount hierarchy, we'll end up
accessing NULL pointer!

Disallow this kind of invalid usage.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

Reading git-diff-tree failed