sch_htb: fix null pointer dereference on a null new_q

sch_htb: fix null pointer dereference on a null new_q

Currently if new_q is null, the null new_q pointer will be
dereference when 'q->offload' is true. Fix this by adding
a braces around htb_parent_to_leaf_offload() to avoid it.

Addresses-Coverity: ("Dereference after null check")
Fixes: d03b195b ("sch_htb: Hierarchical QoS hardware offload")
Signed-off-by: NYunjian Wang <wangyunjian@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_htb.c

@@ -1675,9 +1675,10 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg,
 					  cl->parent->common.classid,
 					  NULL);
 		if (q->offload) {
-			if (new_q)
+			if (new_q) {
 				htb_set_lockdep_class_child(new_q);
-			htb_parent_to_leaf_offload(sch, dev_queue, new_q);
+				htb_parent_to_leaf_offload(sch, dev_queue, new_q);
+			}
 		}
 	}