diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 3afac9c21a76..14a202b5a318 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -427,7 +427,10 @@ static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
 	while (cl->cmode == HTB_MAY_BORROW && p && mask) {
 		m = mask;
 		while (m) {
-			int prio = ffz(~m);
+			unsigned int prio = ffz(~m);
+
+			if (WARN_ON_ONCE(prio > ARRAY_SIZE(p->inner.clprio)))
+				break;
 			m &= ~(1 << prio);
 
 			if (p->inner.clprio[prio].feed.rb_node)