Patch "tcp: initialize icsk_ack.lrcvtime at session start time" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    tcp: initialize icsk_ack.lrcvtime at session start time

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tcp-initialize-icsk_ack.lrcvtime-at-session-start-time.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Mar 27 18:22:09 CEST 2017
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 22 Mar 2017 08:10:21 -0700
Subject: tcp: initialize icsk_ack.lrcvtime at session start time

From: Eric Dumazet <edumazet@google.com>


[ Upstream commit 15bb7745e94a665caf42bfaabf0ce062845b533b ]

icsk_ack.lrcvtime has a 0 value at socket creation time.

tcpi_last_data_recv can have bogus value if no payload is ever received.

This patch initializes icsk_ack.lrcvtime for active sessions
in tcp_finish_connect(), and for passive sessions in
tcp_create_openreq_child()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/tcp_input.c     |    2 +-
 net/ipv4/tcp_minisocks.c |    1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5435,6 +5435,7 @@ void tcp_finish_connect(struct sock *sk,
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
 	tcp_set_state(sk, TCP_ESTABLISHED);
+	icsk->icsk_ack.lrcvtime = tcp_time_stamp;
 
 	if (skb) {
 		icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
@@ -5647,7 +5648,6 @@ static int tcp_rcv_synsent_state_process
 			 * to stand against the temptation 8)     --ANK
 			 */
 			inet_csk_schedule_ack(sk);
-			icsk->icsk_ack.lrcvtime = tcp_time_stamp;
 			tcp_enter_quickack_mode(sk);
 			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 						  TCP_DELACK_MAX, TCP_RTO_MAX);
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -472,6 +472,7 @@ struct sock *tcp_create_openreq_child(co
 		newtp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
 		newtp->rtt_min[0].rtt = ~0U;
 		newicsk->icsk_rto = TCP_TIMEOUT_INIT;
+		newicsk->icsk_ack.lrcvtime = tcp_time_stamp;
 
 		newtp->packets_out = 0;
 		newtp->retrans_out = 0;


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.4/ipv4-provide-stronger-user-input-validation-in-nl_fib_input.patch
queue-4.4/tcp-initialize-icsk_ack.lrcvtime-at-session-start-time.patch
queue-4.4/net-properly-release-sk_frag.page.patch