[NET_SCHED]: sch_htb/sch_hfsc: fix oops in qlen_notify

During both HTB and HFSC class deletion the class is removed from the
class hash before calling qdisc_tree_decrease_qlen. This makes the
->get operation in qdisc_tree_decrease_qlen fail, so it passes a NULL
pointer to ->qlen_notify, causing an oops.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_hfsc.c

@@ -1184,10 +1184,12 @@ hfsc_delete_class(struct Qdisc *sch, unsigned long arg)
 
 	sch_tree_lock(sch);
 
-	list_del(&cl->hlist);
 	list_del(&cl->siblings);
 	hfsc_adjust_levels(cl->cl_parent);
+
 	hfsc_purge_queue(sch, cl);
+	list_del(&cl->hlist);
+
 	if (--cl->refcnt == 0)
 		hfsc_destroy_class(sch, cl);
 

net/sched/sch_htb.c

@@ -1380,15 +1380,15 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg)
 
 	sch_tree_lock(sch);
 
-	/* delete from hash and active; remainder in destroy_class */
-	hlist_del_init(&cl->hlist);
-
 	if (!cl->level) {
 		qlen = cl->un.leaf.q->q.qlen;
 		qdisc_reset(cl->un.leaf.q);
 		qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);
 	}
 
+	/* delete from hash and active; remainder in destroy_class */
+	hlist_del_init(&cl->hlist);
+
 	if (cl->prio_activity)
 		htb_deactivate(q, cl);