This is a note to let you know that I've just added the patch titled tcp_metrics: properly set tp->snd_ssthresh in tcp_init_metrics() to the 5.10-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_metrics-properly-set-tp-snd_ssthresh-in-tcp_init.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 02c942426585b940ddb6dc989a7a343797cee5f2 Author: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Fri Sep 22 22:03:54 2023 +0000 tcp_metrics: properly set tp->snd_ssthresh in tcp_init_metrics() [ Upstream commit 081480014a64a69d901f8ef1ffdd56d6085cf87e ] We need to set tp->snd_ssthresh to TCP_INFINITE_SSTHRESH in the case tcp_get_metrics() fails for some reason. Fixes: 9ad7c049f0f7 ("tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open side") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Reviewed-by: David Ahern <dsahern@xxxxxxxxxx> Acked-by: Neal Cardwell <ncardwell@xxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 03ab7500f5745..a5d4e69acc05d 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -470,6 +470,10 @@ void tcp_init_metrics(struct sock *sk) u32 val, crtt = 0; /* cached RTT scaled by 8 */ sk_dst_confirm(sk); + /* ssthresh may have been reduced unnecessarily during. + * 3WHS. Restore it back to its initial default. + */ + tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; if (!dst) goto reset; @@ -489,11 +493,6 @@ void tcp_init_metrics(struct sock *sk) tp->snd_ssthresh = val; if (tp->snd_ssthresh > tp->snd_cwnd_clamp) tp->snd_ssthresh = tp->snd_cwnd_clamp; - } else { - /* ssthresh may have been reduced unnecessarily during. - * 3WHS. Restore it back to its initial default. - */ - tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; } val = tcp_metric_get(tm, TCP_METRIC_REORDERING); if (val && tp->reordering != val)