From: Li Zefan Subject: [PATCH 1/5] cgroup: fix broken css_has_online_children() Date: Thu, 12 Jun 2014 14:31:31 +0800 Message-ID: <53994943.60703@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo Cc: LKML , Cgroups After running: # mount -t cgroup cpu xxx /cgroup && mkdir /cgroup/sub && \ rmdir /cgroup/sub && umount /cgroup I found the cgroup root still existed: # cat /proc/cgroups #subsys_name hierarchy num_cgroups enabled cpuset 0 1 1 cpu 1 1 1 ... It turned out css_has_online_children() is broken. Signed-off-by: Li Zefan --- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 05b8ca4..1c65f24 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3327,7 +3327,7 @@ bool css_has_online_children(struct cgroup_subsys_state *css) rcu_read_lock(); css_for_each_child(child, css) { - if (css->flags & CSS_ONLINE) { + if (child->flags & CSS_ONLINE) { ret = true; break; } -- 1.8.0.2