Message ID | 1407836714-26813-1-git-send-email-avagin@openvz.org |
---|---|
State | Changes Requested, archived |
Delegated to: | David Miller |
Headers | show |
On Tue, 2014-08-12 at 13:45 +0400, Andrey Vagin wrote: > We don't know right timestamp for repaired skb-s. Wrong RTT estimations > isn't good, because some congestion modules heavily depends on it. > > This patch adds the TCPCB_REPAIRED flag, which is included in > TCPCB_RETRANS. ... > + > + /* All packets are restored as if they have > + * already been sent. skb_mstamp isn't set to > + * avoid wrong rtt estimation. > + */ > + if (tp->repair) { > + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; > + TCP_SKB_CB(skb)->when = tcp_time_stamp; > + } > } > > /* Try to append data to the end of skb. */ Are you sure TCP_SKB_CB(skb)->when needs to be set ? It should not anymore. If yes, I believe a comment would help a lot here. Also, please include this tag to ease stable backports (3.15+) : Fixes: 431a91242d8d ("tcp: timestamp SYN+DATA messages") Fixes: 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution") Thanks ! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Aug 12, 2014 at 05:15:01AM -0700, Eric Dumazet wrote: > On Tue, 2014-08-12 at 13:45 +0400, Andrey Vagin wrote: > > We don't know right timestamp for repaired skb-s. Wrong RTT estimations > > isn't good, because some congestion modules heavily depends on it. > > > > This patch adds the TCPCB_REPAIRED flag, which is included in > > TCPCB_RETRANS. > > ... > > > + > > + /* All packets are restored as if they have > > + * already been sent. skb_mstamp isn't set to > > + * avoid wrong rtt estimation. > > + */ > > + if (tp->repair) { > > + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; > > + TCP_SKB_CB(skb)->when = tcp_time_stamp; > > + } > > } > > > > /* Try to append data to the end of skb. */ > > > Are you sure TCP_SKB_CB(skb)->when needs to be set ? It's used in tcp_rearm_rto() for calculating a retransmit timeout. ... const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto; s32 delta = (s32)(rto_time_stamp - tcp_time_stamp); ... "when" is used as a start point, so I think it's acceptable here. I will add a comment. Thanks. > > It should not anymore. > > If yes, I believe a comment would help a lot here. > > Also, please include this tag to ease stable backports (3.15+) : > > Fixes: 431a91242d8d ("tcp: timestamp SYN+DATA messages") > Fixes: 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution") Thanks, Andrew -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2014-08-12 at 16:33 +0400, Andrew Vagin wrote: > On Tue, Aug 12, 2014 at 05:15:01AM -0700, Eric Dumazet wrote: > > On Tue, 2014-08-12 at 13:45 +0400, Andrey Vagin wrote: > > > We don't know right timestamp for repaired skb-s. Wrong RTT estimations > > > isn't good, because some congestion modules heavily depends on it. > > > > > > This patch adds the TCPCB_REPAIRED flag, which is included in > > > TCPCB_RETRANS. > > > > ... > > > > > + > > > + /* All packets are restored as if they have > > > + * already been sent. skb_mstamp isn't set to > > > + * avoid wrong rtt estimation. > > > + */ > > > + if (tp->repair) { > > > + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; > > > + TCP_SKB_CB(skb)->when = tcp_time_stamp; > > > + } > > > } > > > > > > /* Try to append data to the end of skb. */ > > > > > > Are you sure TCP_SKB_CB(skb)->when needs to be set ? > > It's used in tcp_rearm_rto() for calculating a retransmit timeout. > ... > const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto; > s32 delta = (s32)(rto_time_stamp - tcp_time_stamp); > ... > > "when" is used as a start point, so I think it's acceptable here. > > I will add a comment. Thanks. tcp_rearm_rto() does the following : if (!tp->packets_out) { inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); } else { u32 rto = inet_csk(sk)->icsk_rto; /* Offset the time elapsed after installing regular RTO */ if (icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS || icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { struct sk_buff *skb = tcp_write_queue_head(sk); const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto; This means that : at least one packet was transmitted (packets_out is not 0) Since we timestamp all packets we transmit (look at tcp_transmit_skb() callers, all doing : TCP_SKB_CB(skb)->when = tcp_time_stamp; Then, write queue head was timestamped properly at the time packet was sent, not at the time tcp repair code reinjected skbs into the write queue. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Aug 12, 2014 at 06:14:43AM -0700, Eric Dumazet wrote: > On Tue, 2014-08-12 at 16:33 +0400, Andrew Vagin wrote: > > On Tue, Aug 12, 2014 at 05:15:01AM -0700, Eric Dumazet wrote: > > > On Tue, 2014-08-12 at 13:45 +0400, Andrey Vagin wrote: > > > > We don't know right timestamp for repaired skb-s. Wrong RTT estimations > > > > isn't good, because some congestion modules heavily depends on it. > > > > > > > > This patch adds the TCPCB_REPAIRED flag, which is included in > > > > TCPCB_RETRANS. > > > > > > ... > > > > > > > + > > > > + /* All packets are restored as if they have > > > > + * already been sent. skb_mstamp isn't set to > > > > + * avoid wrong rtt estimation. > > > > + */ > > > > + if (tp->repair) { > > > > + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; > > > > + TCP_SKB_CB(skb)->when = tcp_time_stamp; > > > > + } > > > > } > > > > > > > > /* Try to append data to the end of skb. */ > > > > > > > > > Are you sure TCP_SKB_CB(skb)->when needs to be set ? > > > > It's used in tcp_rearm_rto() for calculating a retransmit timeout. > > ... > > const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto; > > s32 delta = (s32)(rto_time_stamp - tcp_time_stamp); > > ... > > > > "when" is used as a start point, so I think it's acceptable here. > > > > I will add a comment. Thanks. > > tcp_rearm_rto() does the following : > > > if (!tp->packets_out) { > inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); > } else { > u32 rto = inet_csk(sk)->icsk_rto; > /* Offset the time elapsed after installing regular RTO */ > if (icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS || > icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { > struct sk_buff *skb = tcp_write_queue_head(sk); > const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto; > > This means that : at least one packet was transmitted (packets_out is not 0) This one packet may be repaired: static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, int push_one, gfp_t gfp) ... while ((skb = tcp_send_head(sk))) { ... if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE) goto repair; /* Skip network transmission */ ... TCP_SKB_CB(skb)->when = tcp_time_stamp; ... repair: /* Advance the send_head. This one is sent out. * This call will increment packets_out. */ tcp_event_new_data_sent(sk, skb) tp->packets_out += tcp_skb_pcount(skb); } Looks like we need move setting of "when" in tcp_write_xmit, because it is set here for all normal skb-s. > > Since we timestamp all packets we transmit (look at tcp_transmit_skb() callers, all doing : > > TCP_SKB_CB(skb)->when = tcp_time_stamp; > > Then, write queue head was timestamped properly at the time packet was sent, > not at the time tcp repair code reinjected skbs into the write queue. > > > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Aug 12, 2014 at 2:45 AM, Andrey Vagin <avagin@openvz.org> wrote: > We don't know right timestamp for repaired skb-s. Wrong RTT estimations > isn't good, because some congestion modules heavily depends on it. > > This patch adds the TCPCB_REPAIRED flag, which is included in > TCPCB_RETRANS. > > Thanks to Eric for the advice how to fix this issue. > > This patch fixes the warning: > [ 879.562947] WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 tcp_ack+0x11f5/0x1380() > [ 879.567253] CPU: 0 PID: 2825 Comm: socket-tcpbuf-l Not tainted 3.16.0-next-20140811 #1 > [ 879.567829] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > [ 879.568177] 0000000000000000 00000000c532680c ffff880039643d00 ffffffff817aa2d2 > [ 879.568776] 0000000000000000 ffff880039643d38 ffffffff8109afbd ffff880039d6ba80 > [ 879.569386] ffff88003a449800 000000002983d6bd 0000000000000000 000000002983d6bc > [ 879.569982] Call Trace: > [ 879.570264] [<ffffffff817aa2d2>] dump_stack+0x4d/0x66 > [ 879.570599] [<ffffffff8109afbd>] warn_slowpath_common+0x7d/0xa0 > [ 879.570935] [<ffffffff8109b0ea>] warn_slowpath_null+0x1a/0x20 > [ 879.571292] [<ffffffff816d0a05>] tcp_ack+0x11f5/0x1380 > [ 879.571614] [<ffffffff816d10bd>] tcp_rcv_established+0x1ed/0x710 > [ 879.571958] [<ffffffff816dc9da>] tcp_v4_do_rcv+0x10a/0x370 > [ 879.572315] [<ffffffff81657459>] release_sock+0x89/0x1d0 > [ 879.572642] [<ffffffff816c81a0>] do_tcp_setsockopt.isra.36+0x120/0x860 > [ 879.573000] [<ffffffff8110a52e>] ? rcu_read_lock_held+0x6e/0x80 > [ 879.573352] [<ffffffff816c8912>] tcp_setsockopt+0x32/0x40 > [ 879.573678] [<ffffffff81654ac4>] sock_common_setsockopt+0x14/0x20 > [ 879.574031] [<ffffffff816537b0>] SyS_setsockopt+0x80/0xf0 > [ 879.574393] [<ffffffff817b40a9>] system_call_fastpath+0x16/0x1b > [ 879.574730] ---[ end trace a17cbc38eb8c5c00 ]--- > > Cc: Eric Dumazet <edumazet@google.com> > Cc: Pavel Emelyanov <xemul@parallels.com> > Cc: "David S. Miller" <davem@davemloft.net> > Signed-off-by: Andrey Vagin <avagin@openvz.org> > --- > include/net/tcp.h | 4 +++- > net/ipv4/tcp.c | 16 +++++++++------- > 2 files changed, 12 insertions(+), 8 deletions(-) > > diff --git a/include/net/tcp.h b/include/net/tcp.h > index dafa1cb..36f5525 100644 > --- a/include/net/tcp.h > +++ b/include/net/tcp.h > @@ -705,8 +705,10 @@ struct tcp_skb_cb { > #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ > #define TCPCB_LOST 0x04 /* SKB is lost */ > #define TCPCB_TAGBITS 0x07 /* All tag bits */ > +#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */ > #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ > -#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) > +#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ > + TCPCB_REPAIRED) > > __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ > /* 1 byte hole */ > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 181b70e..cb5f548 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -1188,13 +1188,6 @@ new_segment: > goto wait_for_memory; > > /* > - * All packets are restored as if they have > - * already been sent. > - */ > - if (tp->repair) > - TCP_SKB_CB(skb)->when = tcp_time_stamp; > - > - /* > * Check whether we can use HW checksum. > */ > if (sk->sk_route_caps & NETIF_F_ALL_CSUM) > @@ -1203,6 +1196,15 @@ new_segment: > skb_entail(sk, skb); > copy = size_goal; > max = size_goal; > + > + /* All packets are restored as if they have > + * already been sent. skb_mstamp isn't set to > + * avoid wrong rtt estimation. > + */ > + if (tp->repair) { > + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; > + TCP_SKB_CB(skb)->when = tcp_time_stamp; But this still allow RTT samples from TCP timestamp options even if the packet is marked retransmitted/repaired in tcp_ack_update_rtt()? > + } > } > > /* Try to append data to the end of skb. */ > -- > 1.9.3 > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Aug 12, 2014 at 07:53:57AM -0700, Yuchung Cheng wrote: > On Tue, Aug 12, 2014 at 2:45 AM, Andrey Vagin <avagin@openvz.org> wrote: > > We don't know right timestamp for repaired skb-s. Wrong RTT estimations > > isn't good, because some congestion modules heavily depends on it. > > > > This patch adds the TCPCB_REPAIRED flag, which is included in > > TCPCB_RETRANS. > > > > Thanks to Eric for the advice how to fix this issue. > > > > This patch fixes the warning: > > [ 879.562947] WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 tcp_ack+0x11f5/0x1380() > > [ 879.567253] CPU: 0 PID: 2825 Comm: socket-tcpbuf-l Not tainted 3.16.0-next-20140811 #1 > > [ 879.567829] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > > [ 879.568177] 0000000000000000 00000000c532680c ffff880039643d00 ffffffff817aa2d2 > > [ 879.568776] 0000000000000000 ffff880039643d38 ffffffff8109afbd ffff880039d6ba80 > > [ 879.569386] ffff88003a449800 000000002983d6bd 0000000000000000 000000002983d6bc > > [ 879.569982] Call Trace: > > [ 879.570264] [<ffffffff817aa2d2>] dump_stack+0x4d/0x66 > > [ 879.570599] [<ffffffff8109afbd>] warn_slowpath_common+0x7d/0xa0 > > [ 879.570935] [<ffffffff8109b0ea>] warn_slowpath_null+0x1a/0x20 > > [ 879.571292] [<ffffffff816d0a05>] tcp_ack+0x11f5/0x1380 > > [ 879.571614] [<ffffffff816d10bd>] tcp_rcv_established+0x1ed/0x710 > > [ 879.571958] [<ffffffff816dc9da>] tcp_v4_do_rcv+0x10a/0x370 > > [ 879.572315] [<ffffffff81657459>] release_sock+0x89/0x1d0 > > [ 879.572642] [<ffffffff816c81a0>] do_tcp_setsockopt.isra.36+0x120/0x860 > > [ 879.573000] [<ffffffff8110a52e>] ? rcu_read_lock_held+0x6e/0x80 > > [ 879.573352] [<ffffffff816c8912>] tcp_setsockopt+0x32/0x40 > > [ 879.573678] [<ffffffff81654ac4>] sock_common_setsockopt+0x14/0x20 > > [ 879.574031] [<ffffffff816537b0>] SyS_setsockopt+0x80/0xf0 > > [ 879.574393] [<ffffffff817b40a9>] system_call_fastpath+0x16/0x1b > > [ 879.574730] ---[ end trace a17cbc38eb8c5c00 ]--- > > > > Cc: Eric Dumazet <edumazet@google.com> > > Cc: Pavel Emelyanov <xemul@parallels.com> > > Cc: "David S. Miller" <davem@davemloft.net> > > Signed-off-by: Andrey Vagin <avagin@openvz.org> > > --- > > include/net/tcp.h | 4 +++- > > net/ipv4/tcp.c | 16 +++++++++------- > > 2 files changed, 12 insertions(+), 8 deletions(-) > > > > diff --git a/include/net/tcp.h b/include/net/tcp.h > > index dafa1cb..36f5525 100644 > > --- a/include/net/tcp.h > > +++ b/include/net/tcp.h > > @@ -705,8 +705,10 @@ struct tcp_skb_cb { > > #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ > > #define TCPCB_LOST 0x04 /* SKB is lost */ > > #define TCPCB_TAGBITS 0x07 /* All tag bits */ > > +#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */ > > #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ > > -#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) > > +#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ > > + TCPCB_REPAIRED) > > > > __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ > > /* 1 byte hole */ > > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > > index 181b70e..cb5f548 100644 > > --- a/net/ipv4/tcp.c > > +++ b/net/ipv4/tcp.c > > @@ -1188,13 +1188,6 @@ new_segment: > > goto wait_for_memory; > > > > /* > > - * All packets are restored as if they have > > - * already been sent. > > - */ > > - if (tp->repair) > > - TCP_SKB_CB(skb)->when = tcp_time_stamp; > > - > > - /* > > * Check whether we can use HW checksum. > > */ > > if (sk->sk_route_caps & NETIF_F_ALL_CSUM) > > @@ -1203,6 +1196,15 @@ new_segment: > > skb_entail(sk, skb); > > copy = size_goal; > > max = size_goal; > > + > > + /* All packets are restored as if they have > > + * already been sent. skb_mstamp isn't set to > > + * avoid wrong rtt estimation. > > + */ > > + if (tp->repair) { > > + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; > > + TCP_SKB_CB(skb)->when = tcp_time_stamp; > But this still allow RTT samples from TCP timestamp options even if > the packet is marked retransmitted/repaired in tcp_ack_update_rtt()? "when" isn't used there. rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr If a tcp connection is moved from another host, we set tp->tsoffset so, that rcv_tsecr remains coherent with tcp_time_stamp on the target host. > > > + } > > } > > > > /* Try to append data to the end of skb. */ > > -- > > 1.9.3 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe netdev" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/tcp.h b/include/net/tcp.h index dafa1cb..36f5525 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -705,8 +705,10 @@ struct tcp_skb_cb { #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ #define TCPCB_LOST 0x04 /* SKB is lost */ #define TCPCB_TAGBITS 0x07 /* All tag bits */ +#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */ #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ -#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) +#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ + TCPCB_REPAIRED) __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ /* 1 byte hole */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 181b70e..cb5f548 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1188,13 +1188,6 @@ new_segment: goto wait_for_memory; /* - * All packets are restored as if they have - * already been sent. - */ - if (tp->repair) - TCP_SKB_CB(skb)->when = tcp_time_stamp; - - /* * Check whether we can use HW checksum. */ if (sk->sk_route_caps & NETIF_F_ALL_CSUM) @@ -1203,6 +1196,15 @@ new_segment: skb_entail(sk, skb); copy = size_goal; max = size_goal; + + /* All packets are restored as if they have + * already been sent. skb_mstamp isn't set to + * avoid wrong rtt estimation. + */ + if (tp->repair) { + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; + TCP_SKB_CB(skb)->when = tcp_time_stamp; + } } /* Try to append data to the end of skb. */
We don't know right timestamp for repaired skb-s. Wrong RTT estimations isn't good, because some congestion modules heavily depends on it. This patch adds the TCPCB_REPAIRED flag, which is included in TCPCB_RETRANS. Thanks to Eric for the advice how to fix this issue. This patch fixes the warning: [ 879.562947] WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 tcp_ack+0x11f5/0x1380() [ 879.567253] CPU: 0 PID: 2825 Comm: socket-tcpbuf-l Not tainted 3.16.0-next-20140811 #1 [ 879.567829] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 879.568177] 0000000000000000 00000000c532680c ffff880039643d00 ffffffff817aa2d2 [ 879.568776] 0000000000000000 ffff880039643d38 ffffffff8109afbd ffff880039d6ba80 [ 879.569386] ffff88003a449800 000000002983d6bd 0000000000000000 000000002983d6bc [ 879.569982] Call Trace: [ 879.570264] [<ffffffff817aa2d2>] dump_stack+0x4d/0x66 [ 879.570599] [<ffffffff8109afbd>] warn_slowpath_common+0x7d/0xa0 [ 879.570935] [<ffffffff8109b0ea>] warn_slowpath_null+0x1a/0x20 [ 879.571292] [<ffffffff816d0a05>] tcp_ack+0x11f5/0x1380 [ 879.571614] [<ffffffff816d10bd>] tcp_rcv_established+0x1ed/0x710 [ 879.571958] [<ffffffff816dc9da>] tcp_v4_do_rcv+0x10a/0x370 [ 879.572315] [<ffffffff81657459>] release_sock+0x89/0x1d0 [ 879.572642] [<ffffffff816c81a0>] do_tcp_setsockopt.isra.36+0x120/0x860 [ 879.573000] [<ffffffff8110a52e>] ? rcu_read_lock_held+0x6e/0x80 [ 879.573352] [<ffffffff816c8912>] tcp_setsockopt+0x32/0x40 [ 879.573678] [<ffffffff81654ac4>] sock_common_setsockopt+0x14/0x20 [ 879.574031] [<ffffffff816537b0>] SyS_setsockopt+0x80/0xf0 [ 879.574393] [<ffffffff817b40a9>] system_call_fastpath+0x16/0x1b [ 879.574730] ---[ end trace a17cbc38eb8c5c00 ]--- Cc: Eric Dumazet <edumazet@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrey Vagin <avagin@openvz.org> --- include/net/tcp.h | 4 +++- net/ipv4/tcp.c | 16 +++++++++------- 2 files changed, 12 insertions(+), 8 deletions(-)