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 4.9-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-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Mon Mar 27 18:17:54 CEST 2017 From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Wed, 22 Mar 2017 08:10:21 -0700 Subject: tcp: initialize icsk_ack.lrcvtime at session start time From: Eric Dumazet <edumazet@xxxxxxxxxx> [ 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@xxxxxxxxxx> Acked-by: Neal Cardwell <ncardwell@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -5571,6 +5571,7 @@ 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); @@ -5789,7 +5790,6 @@ 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 @@ -466,6 +466,7 @@ struct sock *tcp_create_openreq_child(co newtp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT); minmax_reset(&newtp->rtt_min, tcp_time_stamp, ~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@xxxxxxxxxx are queue-4.9/ipv4-provide-stronger-user-input-validation-in-nl_fib_input.patch queue-4.9/tcp-initialize-icsk_ack.lrcvtime-at-session-start-time.patch queue-4.9/net-properly-release-sk_frag.page.patch