@@ -606,6 +623,11 @@ static const u8 prio2band[TC_PRIO_MAX + 1] = {
  */
 struct pfifo_fast_priv {
 	struct skb_array q[PFIFO_FAST_BANDS];
+
+	/* protect against data race between enqueue/dequeue and
+	 * qdisc->empty setting
+	 */
+	spinlock_t lock;
 };
 
 static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,

@@ -623,7 +645,10 @@ static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
 	unsigned int pkt_len = qdisc_pkt_len(skb);
 	int err;
 
-	err = skb_array_produce(q, skb);
+	spin_lock(&priv->lock);
+	err = __ptr_ring_produce(&q->ring, skb);
+	WRITE_ONCE(qdisc->empty, false);
+	spin_unlock(&priv->lock);
 
 	if (unlikely(err)) {
 		if (qdisc_is_percpu_stats(qdisc))

@@ -642,6 +667,7 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
 	struct sk_buff *skb = NULL;
 	int band;
 
+	spin_lock(&priv->lock);
 	for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
 		struct skb_array *q = band2list(priv, band);
 

@@ -655,6 +681,7 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
 	} else {
 		WRITE_ONCE(qdisc->empty, true);
 	}
+	spin_unlock(&priv->lock);
 
 	return skb;
 }