[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>

2 files changed, 6 insertions, 4 deletions

diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 396deb71480f..407c6fb1ba14 100644
--- a/net/sched/sch_hfsc.c
+++ b/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);
 
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 97cbb9aec946..3c3294d01041 100644
--- a/net/sched/sch_htb.c
+++ b/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);