PROBLEM: IPv6 TCP-Connections resetting

[Tetja Rediske <tetja@tetja.de>]

Hi,

[1.] One line summary of the problem:

IPv6 TCP-Connections resetting 

[2.] Full description of the problem/report:

In the last weeks we updated some of our systems to a 3.8.4 Kernel.
Since then sometimes we can't connect to services running IPv6,
Apache and Openssh tested. 

We got this on different machines with x86 and x86_64 Kernels. On
x86_64 it is more random, but on x86 i can reproduce it permanently
(Just opening any TCP Connection 1st time or after some short delay).
Connecting quick after the reset again will work as expected. It will
also work, if you keep another connection open.

Before I got to the Kernel, I just kept an strace on an userspace
process, but it did not notice the connection attempt. After this I
monitored the connection with tcpdump, but nothing unusual.

Then I did a rollback to the older Kernel and it worked as expected.

I tracked it down with 'git bisect' to commit:

  093d04d42fa094f6740bb188f0ad0c215ff61e2c

I also tested latest git state available.

[3.] Keywords (i.e., modules, networking, kernel):

networking, IPv6

[4.] Kernel information
[4.1.] Kernel version (from /proc/version): 

  since commit: 093d04d42fa094f6740bb188f0ad0c215ff61e2c

[4.2.] Kernel .config file:
[5.] Most recent kernel version which did not have the bug:

none

[6.] Output of Oops.. message (if applicable) with symbolic information
     resolved (see Documentation/oops-tracing.txt)
[7.] A small shell script or example program which triggers the
     problem (if possible)
[8.] Environment
[8.1.] Software (add the output of the ver_linux script here)

Different systems, mostly reproduced on this one:

Linux dns03.tetja.de 3.9.0-rc5+ #10 SMP Fri Apr 5 16:55:54 CEST 2013
i686 AMD Athlon(tm) 64 X2 Dual Core Processor 5600+ AuthenticAMD
GNU/Linux

Gnu C                  4.4.5
Gnu make               3.82
binutils               2.22
util-linux             2.22.2
mount                  debug
module-init-tools      12
e2fsprogs              1.42
jfsutils               1.1.15
reiserfsprogs          3.6.21
xfsprogs               3.1.10
Linux C Library        2.15
Dynamic linker (ldd)   2.15
Procps                 3.3.4
Net-tools              1.60_p20120127084908
Kbd                    1.15.3wip
Sh-utils               8.20
Modules Loaded

Connections looking like this on booth sites:

11:52:04.634315 IP6 2a00:1828:0:1::10.51808 >
2a00:1828:1000:1102::2.80: Flags [S], seq 103067898, win 5760, options
[mss 1440,sackOK,TS val 232579708 ecr 0,nop,wscale 7], length 0

11:52:04.634354 IP6 2a00:1828:1000:1102::2.80 >
2a00:1828:0:1::10.51808: Flags [S.], seq 3352491415, ack 103067899, win
14280, options [mss 1440,sackOK,TS val 174797959 ecr
232579708,nop,wscale 7], length 0 

11:52:04.634656 IP6 fe80::92e2:baff:fe00:c120 > 2a00:1828:1000:1102::2:
ICMP6, redirect, 2a00:1828:0:1::10 to 2a00:1828:0:1::10, length 136

11:52:04.634715 IP6 2a00:1828:0:1::10.51808 >
2a00:1828:1000:1102::2.80: Flags [.], ack 1, win 45, options
[nop,nop,TS val 232579708 ecr 174797959], length 0

11:52:04.634726 IP6 2a00:1828:1000:1102::2.80 >
2a00:1828:0:1::10.51808: Flags [R], seq 3352491416, win 0, length 0

11:52:04.635027 IP6 2a00:1828:0:1::10.51808 >
2a00:1828:1000:1102::2.80: Flags [P.], seq 1:359, ack 1, win 45,
options [nop,nop,TS val 232579708 ecr 174797959], length 358

11:52:04.635037 IP6 2a00:1828:1000:1102::2.80 >
2a00:1828:0:1::10.51808: Flags [R], seq 3352491416, win 0, length 0

11:52:04.635071 IP6 fe80::92e2:baff:fe00:c120 > 2a00:1828:1000:1102::2:
ICMP6, redirect, 2a00:1828:0:1::10 to 2a00:1828:0:1::10, length 112

11:52:04.635246 IP6 fe80::92e2:baff:fe00:c120 > 2a00:1828:1000:1102::2:
ICMP6, redirect, 2a00:1828:0:1::10 to 2a00:1828:0:1::10, length 112

Kind Regards and keep up the good work! :)

Tetja Rediske