pkt_sched: Fix oops in htb_delete.

Recent changes introduced a bug in htb_delete(): cl->parent->children
counter update misses checking cl->parent for NULL, which is used for
root classes, so deleting them causes an oops.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index be35422711a3..6febd245e62b 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1279,7 +1279,8 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg)
 
         /* delete from hash and active; remainder in destroy_class */
         qdisc_class_hash_remove(&q->clhash, &cl->common);
-        cl->parent->children--;
+        if (cl->parent)
+                cl->parent->children--;
 
         if (cl->prio_activity)
                 htb_deactivate(q, cl);