• Andrey Vagin's avatar
    tcp: don't use timestamp from repaired skb-s to calculate RTT (v2) · 48518112
    Andrey Vagin authored
    [ Upstream commit 9d186cac ]
    
    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 ]---
    
    v2: moving setting of skb->when for repaired skb-s in tcp_write_xmit,
        where it's set for other skb-s.
    
    Fixes: 431a9124 ("tcp: timestamp SYN+DATA messages")
    Fixes: 740b0f18 ("tcp: switch rtt estimations to usec resolution")
    Cc: Eric Dumazet <edumazet@google.com>
    Cc: Pavel Emelyanov <xemul@parallels.com>
    Cc: "David S. Miller" <davem@davemloft.net>
    Signed-off-by: default avatarAndrey Vagin <avagin@openvz.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    48518112
tcp_output.c 95 KB