[PATCH net-next] tcp: tcp_rack_reo_timeout() must update tp->tcp_mstamp

[PATCH net-next] tcp: tcp_rack_reo_timeout() must update tp->tcp_mstamp

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

I wrongly assumed tp->tcp_mstamp was up to date at the time
tcp_rack_reo_timeout() was called.

It is not true, since we only update tcp->tcp_mstamp when receiving
a packet (as initially done in commit 69e996c58a35 ("tcp: add
tp->tcp_mstamp field")

tcp_rack_reo_timeout() being called by a timer and not an incoming
packet, we need to refresh tp->tcp_mstamp

Fixes: 7c1c7308592f ("tcp: do not pass timestamp to tcp_rack_detect_loss()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
---
 net/ipv4/tcp_recovery.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
index cd72b3d3879e88181c8a4639f0334a24e4cda852..362b8c75bfab44cf87c2a01398a146a271bc1119 100644
--- a/net/ipv4/tcp_recovery.c
+++ b/net/ipv4/tcp_recovery.c
@@ -166,6 +166,7 @@ void tcp_rack_reo_timeout(struct sock *sk)
 	u32 timeout, prior_inflight;
 
 	prior_inflight = tcp_packets_in_flight(tp);
+	skb_mstamp_get(&tp->tcp_mstamp);
 	tcp_rack_detect_loss(sk, &timeout);
 	if (prior_inflight != tcp_packets_in_flight(tp)) {
 		if (inet_csk(sk)->icsk_ca_state != TCP_CA_Recovery) {

Re: [PATCH net-next] tcp: tcp_rack_reo_timeout() must update tp->tcp_mstamp

[Soheil Hassas Yeganeh]

On Thu, Apr 27, 2017 at 12:10 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> I wrongly assumed tp->tcp_mstamp was up to date at the time
> tcp_rack_reo_timeout() was called.
>
> It is not true, since we only update tcp->tcp_mstamp when receiving
> a packet (as initially done in commit 69e996c58a35 ("tcp: add
> tp->tcp_mstamp field")
>
> tcp_rack_reo_timeout() being called by a timer and not an incoming
> packet, we need to refresh tp->tcp_mstamp
>
> Fixes: 7c1c7308592f ("tcp: do not pass timestamp to tcp_rack_detect_loss()")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Acked-by: Soheil Hassas Yeganeh <soheil@google.com>

> Cc: Soheil Hassas Yeganeh <soheil@google.com>
> Cc: Neal Cardwell <ncardwell@google.com>
> Cc: Yuchung Cheng <ycheng@google.com>
> ---
>  net/ipv4/tcp_recovery.c |    1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
> index cd72b3d3879e88181c8a4639f0334a24e4cda852..362b8c75bfab44cf87c2a01398a146a271bc1119 100644
> --- a/net/ipv4/tcp_recovery.c
> +++ b/net/ipv4/tcp_recovery.c
> @@ -166,6 +166,7 @@ void tcp_rack_reo_timeout(struct sock *sk)
>         u32 timeout, prior_inflight;
>
>         prior_inflight = tcp_packets_in_flight(tp);
> +       skb_mstamp_get(&tp->tcp_mstamp);
>         tcp_rack_detect_loss(sk, &timeout);
>         if (prior_inflight != tcp_packets_in_flight(tp)) {
>                 if (inet_csk(sk)->icsk_ca_state != TCP_CA_Recovery) {
>
>

Thanks for the fix!

Re: [PATCH net-next] tcp: tcp_rack_reo_timeout() must update tp->tcp_mstamp

[Neal Cardwell]

On Thu, Apr 27, 2017 at 12:10 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> I wrongly assumed tp->tcp_mstamp was up to date at the time
> tcp_rack_reo_timeout() was called.
>
> It is not true, since we only update tcp->tcp_mstamp when receiving
> a packet (as initially done in commit 69e996c58a35 ("tcp: add
> tp->tcp_mstamp field")
>
> tcp_rack_reo_timeout() being called by a timer and not an incoming
> packet, we need to refresh tp->tcp_mstamp
>
> Fixes: 7c1c7308592f ("tcp: do not pass timestamp to tcp_rack_detect_loss()")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Soheil Hassas Yeganeh <soheil@google.com>
> Cc: Neal Cardwell <ncardwell@google.com>
> Cc: Yuchung Cheng <ycheng@google.com>

Acked-by: Neal Cardwell <ncardwell@google.com>

Thanks!

neal

Re: [PATCH net-next] tcp: tcp_rack_reo_timeout() must update tp->tcp_mstamp

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 26 Apr 2017 21:10:55 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> I wrongly assumed tp->tcp_mstamp was up to date at the time
> tcp_rack_reo_timeout() was called.
> 
> It is not true, since we only update tcp->tcp_mstamp when receiving
> a packet (as initially done in commit 69e996c58a35 ("tcp: add
> tp->tcp_mstamp field")
> 
> tcp_rack_reo_timeout() being called by a timer and not an incoming
> packet, we need to refresh tp->tcp_mstamp
> 
> Fixes: 7c1c7308592f ("tcp: do not pass timestamp to tcp_rack_detect_loss()")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied, thanks Eric.