Hello, Daniel.

On Tue, Nov 20, 2012 at 09:57:14AM +0100, Daniel Wagner wrote:

quoted

-static void cgrp_css_free(struct cgroup *cgrp)
+static int cgrp_css_online(struct cgroup *cgrp)
 {
-	struct cgroup_netprio_state *cs = cgrp_netprio_state(cgrp);
+	struct cgroup *parent = cgrp->parent;
 	struct net_device *dev;
+	int ret = 0;
+
+	if (!parent)
+		return 0;

BTW, parent is always != NULL, because the root cgroup will be
attached to the dummytop cgroup.

Hmmm?  I'm confused.  When ->css_online() is called for dummytop in
cgroup_init_subsys(), its parent is NULL.  What am I missing?

Thanks.

-- 
tejun