diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 8bd30976cdee767fbeb5e1eef3b693cc6bdc0025..6db77d1329f7fe6fd63a099a583b9d7dc8dad7dd 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -621,7 +621,13 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 	/* The receiver of the HEARTBEAT ACK should also perform an
 	 * RTT measurement for that destination transport address
 	 * using the time value carried in the HEARTBEAT ACK chunk.
+	 * If the transport's rto_pending variable has been cleared,
+	 * it was most likely due to a retransmit.  However, we want
+	 * to re-enable it to properly update the rto.
 	 */
+	if (t->rto_pending == 0)
+		t->rto_pending = 1;
+
 	hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 	sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));