diff --git a/include/net/tcp.h b/include/net/tcp.h
index 68e67b79534b8c0a26dcbbc69636ea3cdd1dfd1c..aa7bc211e95f77d3a54b3d924f9072143fd3de7c 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -796,6 +796,12 @@ static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
 	return div_u64(skb->skb_mstamp, USEC_PER_SEC / TCP_TS_HZ);
 }
 
+/* provide the departure time in us unit */
+static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb)
+{
+	return skb->skb_mstamp;
+}
+
 
 #define tcp_flag_byte(th) (((u_int8_t *)th)[13])
 
@@ -2001,9 +2007,26 @@ static inline s64 tcp_rto_delta_us(const struct sock *sk)
 {
 	const struct sk_buff *skb = tcp_rtx_queue_head(sk);
 	u32 rto = inet_csk(sk)->icsk_rto;
-	u64 rto_time_stamp_us = skb->skb_mstamp + jiffies_to_usecs(rto);
 
-	return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp;
+	if (likely(skb)) {
+		u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto);
+
+		return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp;
+	} else {
+		WARN_ONCE(1,
+			"rtx queue emtpy: "
+			"out:%u sacked:%u lost:%u retrans:%u "
+			"tlp_high_seq:%u sk_state:%u ca_state:%u "
+			"advmss:%u mss_cache:%u pmtu:%u\n",
+			tcp_sk(sk)->packets_out, tcp_sk(sk)->sacked_out,
+			tcp_sk(sk)->lost_out, tcp_sk(sk)->retrans_out,
+			tcp_sk(sk)->tlp_high_seq, sk->sk_state,
+			inet_csk(sk)->icsk_ca_state,
+			tcp_sk(sk)->advmss, tcp_sk(sk)->mss_cache,
+			inet_csk(sk)->icsk_pmtu_cookie);
+		return jiffies_to_usecs(rto);
+	}
+
 }
 
 /*
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a577d68b80cb8bf8f092b13cd6aca8ab73ed44a6..6b98946a42db0b917dfc96066f8b4a43fd498697 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1288,7 +1288,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
 	 */
 	tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
 			start_seq, end_seq, dup_sack, pcount,
-			skb->skb_mstamp);
+			tcp_skb_timestamp_us(skb));
 	tcp_rate_skb_delivered(sk, skb, state->rate);
 
 	if (skb == tp->lost_skb_hint)
@@ -1577,7 +1577,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 						TCP_SKB_CB(skb)->end_seq,
 						dup_sack,
 						tcp_skb_pcount(skb),
-						skb->skb_mstamp);
+						tcp_skb_timestamp_us(skb));
 			tcp_rate_skb_delivered(sk, skb, state->rate);
 			if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
 				list_del_init(&skb->tcp_tsorted_anchor);
@@ -3127,7 +3127,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
 				tp->retrans_out -= acked_pcount;
 			flag |= FLAG_RETRANS_DATA_ACKED;
 		} else if (!(sacked & TCPCB_SACKED_ACKED)) {
-			last_ackt = skb->skb_mstamp;
+			last_ackt = tcp_skb_timestamp_us(skb);
 			WARN_ON_ONCE(last_ackt == 0);
 			if (!first_ackt)
 				first_ackt = last_ackt;
@@ -3145,7 +3145,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
 			tp->delivered += acked_pcount;
 			if (!tcp_skb_spurious_retrans(tp, skb))
 				tcp_rack_advance(tp, sacked, scb->end_seq,
-						 skb->skb_mstamp);
+						 tcp_skb_timestamp_us(skb));
 		}
 		if (sacked & TCPCB_LOST)
 			tp->lost_out -= acked_pcount;
@@ -3240,7 +3240,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
 			tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta);
 		}
 	} else if (skb && rtt_update && sack_rtt_us >= 0 &&
-		   sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp)) {
+		   sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp,
+						    tcp_skb_timestamp_us(skb))) {
 		/* Do not re-arm RTO if the sack RTT is measured from data sent
 		 * after when the head was last (re)transmitted. Otherwise the
 		 * timeout may continue to extend in loss recovery.
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index de947bbaeda215c8ee04fc1d72802ed78ffc20f9..e90aff4b855aef67d6a785fbee0db522c0568243 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -554,7 +554,7 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
 
 		tcp_mstamp_refresh(tp);
-		delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp);
+		delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
 		remaining = icsk->icsk_rto -
 			    usecs_to_jiffies(delta_us);
 
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index cb316218cb4932e0f7c31ae9e9b4aac6b8fbbca7..af6aa4b93c1eb55c4f14723edcb21ad9d059f0c4 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2046,7 +2046,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 	head = tcp_rtx_queue_head(sk);
 	if (!head)
 		goto send_now;
-	age = tcp_stamp_us_delta(tp->tcp_mstamp, head->skb_mstamp);
+	age = tcp_stamp_us_delta(tp->tcp_mstamp, tcp_skb_timestamp_us(head));
 	/* If next ACK is likely to come too late (half srtt), do not defer */
 	if (age < (tp->srtt_us >> 4))
 		goto send_now;
diff --git a/net/ipv4/tcp_rate.c b/net/ipv4/tcp_rate.c
index 4dff40dad4dc5ccc372f5108b0d6ba38497ab81f..baed2186c7c623737c739cbc1e35a3c772a8b15a 100644
--- a/net/ipv4/tcp_rate.c
+++ b/net/ipv4/tcp_rate.c
@@ -55,8 +55,10 @@ void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb)
 	  * bandwidth estimate.
 	  */
 	if (!tp->packets_out) {
-		tp->first_tx_mstamp  = skb->skb_mstamp;
-		tp->delivered_mstamp = skb->skb_mstamp;
+		u64 tstamp_us = tcp_skb_timestamp_us(skb);
+
+		tp->first_tx_mstamp  = tstamp_us;
+		tp->delivered_mstamp = tstamp_us;
 	}
 
 	TCP_SKB_CB(skb)->tx.first_tx_mstamp	= tp->first_tx_mstamp;
@@ -88,13 +90,12 @@ void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
 		rs->is_app_limited   = scb->tx.is_app_limited;
 		rs->is_retrans	     = scb->sacked & TCPCB_RETRANS;
 
+		/* Record send time of most recently ACKed packet: */
+		tp->first_tx_mstamp  = tcp_skb_timestamp_us(skb);
 		/* Find the duration of the "send phase" of this window: */
-		rs->interval_us      = tcp_stamp_us_delta(
-						skb->skb_mstamp,
-						scb->tx.first_tx_mstamp);
+		rs->interval_us = tcp_stamp_us_delta(tp->first_tx_mstamp,
+						     scb->tx.first_tx_mstamp);
 
-		/* Record send time of most recently ACKed packet: */
-		tp->first_tx_mstamp  = skb->skb_mstamp;
 	}
 	/* Mark off the skb delivered once it's sacked to avoid being
 	 * used again when it's cumulatively acked. For acked packets
diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
index 844ff390f7263ec061559d5ebd1396b59dae7fa6..db3469c95c49d8d506ea3878fbd00096d6ba1d2e 100644
--- a/net/ipv4/tcp_recovery.c
+++ b/net/ipv4/tcp_recovery.c
@@ -51,7 +51,7 @@ static u32 tcp_rack_reo_wnd(const struct sock *sk)
 s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, u32 reo_wnd)
 {
 	return tp->rack.rtt_us + reo_wnd -
-	       tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);
+	       tcp_stamp_us_delta(tp->tcp_mstamp, tcp_skb_timestamp_us(skb));
 }
 
 /* RACK loss detection (IETF draft draft-ietf-tcpm-rack-01):
@@ -92,7 +92,8 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout)
 		    !(scb->sacked & TCPCB_SACKED_RETRANS))
 			continue;
 
-		if (!tcp_rack_sent_after(tp->rack.mstamp, skb->skb_mstamp,
+		if (!tcp_rack_sent_after(tp->rack.mstamp,
+					 tcp_skb_timestamp_us(skb),
 					 tp->rack.end_seq, scb->end_seq))
 			break;