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| author | Yuchung Cheng <ycheng@google.com> | 2017-08-01 13:22:32 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-02 10:51:07 -0700 |
| commit | ed254971edea92c3ac5c67c6a05247a92aa6075e (patch) | |
| tree | 06c4b0d9564476c2ba90bdfb19b171a5cdf17bb1 | |
| parent | 4d96f12a072c669d48dc3a2c6b539a9faeca138d (diff) | |
| download | linux-ed254971edea92c3ac5c67c6a05247a92aa6075e.tar.gz | |
tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states
If the sender switches the congestion control during ECN-triggered cwnd-reduction state (CA_CWR), upon exiting recovery cwnd is set to the ssthresh value calculated by the previous congestion control. If the previous congestion control is BBR that always keep ssthresh to TCP_INIFINITE_SSTHRESH, cwnd ends up being infinite. The safe step is to avoid assigning invalid ssthresh value when recovery ends. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_input.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 2920e0cb09f8..dad026fcfd09 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2520,8 +2520,8 @@ static inline void tcp_end_cwnd_reduction(struct sock *sk) return; /* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */ - if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || - (tp->undo_marker && tp->snd_ssthresh < TCP_INFINITE_SSTHRESH)) { + if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH && + (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) { tp->snd_cwnd = tp->snd_ssthresh; tp->snd_cwnd_stamp = tcp_jiffies32; } |