Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1710063

[PATCH 4.12 03/17] tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states

Show all headers | View raw

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yuchung Cheng <ycheng@google.com>


[ Upstream commit ed254971edea92c3ac5c67c6a05247a92aa6075e ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/tcp_input.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2517,8 +2517,8 @@ static inline void tcp_end_cwnd_reductio
 		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_time_stamp;
 	}

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 4.12 00/17] 4.12.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:10 +0200
  [PATCH 4.12 12/17] net: avoid skb_warn_bad_offload false positives on UFO Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 06/17] bpf, s390: fix jit branch offset related to ldimm64 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 15/17] packet: fix tp_reserve race in packet_set_ring Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 08/17] net: sched: set xt_tgchk_param par.net properly in ipt_init_target Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 14/17] udp: consistently apply ufo or fragmentation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 09/17] net: sched: set xt_tgchk_param par.nft_compat as 0 in ipt_init_target Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 16/17] scsi: sg: only check for dxfer_len greater than 256M Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 05/17] ipv6: set rt6i_protocol properly in the route when it is installed Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 10/17] tcp: fastopen: tcp_connect() must refresh the route Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 04/17] net: fix keepalive code vs TCP_FASTOPEN_CONNECT Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 07/17] net/mlx4_en: dont set CHECKSUM_COMPLETE on SCTP packets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 02/17] ppp: fix xmit recursion detection on ppp channels Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  [PATCH 4.12 03/17] tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 00:20 +0200
  Re: [PATCH 4.12 00/17] 4.12.7-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-08-12 04:00 +0200
    Re: [PATCH 4.12 00/17] 4.12.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 16:40 +0200
  Re: [PATCH 4.12 00/17] 4.12.7-stable review Guenter Roeck <linux@roeck-us.net> - 2017-08-12 14:30 +0200
    Re: [PATCH 4.12 00/17] 4.12.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-12 18:10 +0200

csiph-web