diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c
index b2905b0..2eaac2f 100644
--- a/net/sched/sch_cbs.c
+++ b/net/sched/sch_cbs.c
@@ -181,6 +181,11 @@
 	s64 credits;
 	int len;
 
+	/* The previous packet is still being sent */
+	if (now < q->last) {
+		qdisc_watchdog_schedule_ns(&q->watchdog, q->last);
+		return NULL;
+	}
 	if (q->credits < 0) {
 		credits = timediff_to_credits(now - q->last, q->idleslope);
 
@@ -212,7 +217,12 @@
 	credits += q->credits;
 
 	q->credits = max_t(s64, credits, q->locredit);
-	q->last = now;
+	/* Estimate of the transmission of the last byte of the packet in ns */
+	if (unlikely(atomic64_read(&q->port_rate) == 0))
+		q->last = now;
+	else
+		q->last = now + div64_s64(len * NSEC_PER_SEC,
+					  atomic64_read(&q->port_rate));
 
 	return skb;
 }