diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index b19e4cd08ed6f269434a6bc8ba32d994589b088f..240754adea8e6ed14399f7728338db364a58a467 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -113,6 +113,7 @@
 
 #define QFQ_MTU_SHIFT		16	/* to support TSO/GSO */
 #define QFQ_MIN_LMAX		512	/* see qfq_slot_insert */
+#define QFQ_MAX_LMAX		(1UL << QFQ_MTU_SHIFT)
 
 #define QFQ_MAX_AGG_CLASSES	8 /* max num classes per aggregate allowed */
 
@@ -375,8 +376,13 @@ static int qfq_change_agg(struct Qdisc *sch, struct qfq_class *cl, u32 weight,
 			   u32 lmax)
 {
 	struct qfq_sched *q = qdisc_priv(sch);
-	struct qfq_aggregate *new_agg = qfq_find_agg(q, lmax, weight);
+	struct qfq_aggregate *new_agg;
 
+	/* 'lmax' can range from [QFQ_MIN_LMAX, pktlen + stab overhead] */
+	if (lmax > QFQ_MAX_LMAX)
+		return -EINVAL;
+
+	new_agg = qfq_find_agg(q, lmax, weight);
 	if (new_agg == NULL) { /* create new aggregate */
 		new_agg = kzalloc(sizeof(*new_agg), GFP_ATOMIC);
 		if (new_agg == NULL)