diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c7398f05d12b..b85bc7c3736a 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1048,6 +1048,7 @@ struct tcp_sacktag_state {
 	int reord;
 	int fack_count;
 	int flag;
+	s32 rtt; /* RTT measured by SACKing never-retransmitted data */
 };
 
 /* Check if skb is fully within the SACK block. In presence of GSO skbs,
@@ -1108,7 +1109,7 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
 static u8 tcp_sacktag_one(struct sock *sk,
 			  struct tcp_sacktag_state *state, u8 sacked,
 			  u32 start_seq, u32 end_seq,
-			  bool dup_sack, int pcount)
+			  int dup_sack, int pcount, u32 xmit_time)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	int fack_count = state->fack_count;
@@ -1148,6 +1149,9 @@ static u8 tcp_sacktag_one(struct sock *sk,
 							   state->reord);
 				if (!after(end_seq, tp->high_seq))
 					state->flag |= FLAG_ORIG_SACK_ACKED;
+				/* Pick the earliest sequence sacked for RTT */
+				if (state->rtt < 0)
+					state->rtt = tcp_time_stamp - xmit_time;
 			}
 
 			if (sacked & TCPCB_LOST) {
@@ -1205,7 +1209,8 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 	 * tcp_highest_sack_seq() when skb is highest_sack.
 	 */
 	tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
-			start_seq, end_seq, dup_sack, pcount);
+			start_seq, end_seq, dup_sack, pcount,
+			TCP_SKB_CB(skb)->when);
 
 	if (skb == tp->lost_skb_hint)
 		tp->lost_cnt_hint += pcount;
@@ -1479,7 +1484,8 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 						TCP_SKB_CB(skb)->seq,
 						TCP_SKB_CB(skb)->end_seq,
 						dup_sack,
-						tcp_skb_pcount(skb));
+						tcp_skb_pcount(skb),
+						TCP_SKB_CB(skb)->when);
 
 			if (!before(TCP_SKB_CB(skb)->seq,
 				    tcp_highest_sack_seq(tp)))
@@ -1536,7 +1542,7 @@ static int tcp_sack_cache_ok(const struct tcp_sock *tp, const struct tcp_sack_bl
 
 static int
 tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
-			u32 prior_snd_una)
+			u32 prior_snd_una, s32 *sack_rtt)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	const unsigned char *ptr = (skb_transport_header(ack_skb) +
@@ -1554,6 +1560,7 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
 
 	state.flag = 0;
 	state.reord = tp->packets_out;
+	state.rtt = -1;
 
 	if (!tp->sacked_out) {
 		if (WARN_ON(tp->fackets_out))
@@ -1737,6 +1744,7 @@ out:
 	WARN_ON((int)tp->retrans_out < 0);
 	WARN_ON((int)tcp_packets_in_flight(tp) < 0);
 #endif
+	*sack_rtt = state.rtt;
 	return state.flag;
 }
 
@@ -3254,6 +3262,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	int prior_packets = tp->packets_out;
 	const int prior_unsacked = tp->packets_out - tp->sacked_out;
 	int acked = 0; /* Number of packets newly acked */
+	s32 sack_rtt = -1;
 
 	/* If the ack is older than previous acks
 	 * then we can probably ignore it.
@@ -3310,7 +3319,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 		flag |= tcp_ack_update_window(sk, skb, ack, ack_seq);
 
 		if (TCP_SKB_CB(skb)->sacked)
-			flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una);
+			flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
+							&sack_rtt);
 
 		if (TCP_ECN_rcv_ecn_echo(tp, tcp_hdr(skb)))
 			flag |= FLAG_ECE;
@@ -3382,7 +3392,8 @@ old_ack:
 	 * If data was DSACKed, see if we can undo a cwnd reduction.
 	 */
 	if (TCP_SKB_CB(skb)->sacked) {
-		flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una);
+		flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
+						&sack_rtt);
 		tcp_fastretrans_alert(sk, acked, prior_unsacked,
 				      is_dupack, flag);
 	}