Re: 2.6.17-rc4: netfilter LOG messages truncated via NETCONSOLE

On Wed, May 31, 2006 at 04:57:13PM +0200, Patrick McHardy wrote:
Frank van Maarseveen wrote:
I have two machines named "porvoo" and "espoo". The first one
has netconsole configured to send kernel messages to UDP port 514
(a.k.a. syslog) on the other machine.

Somewhere between 2.6.13.2 and 2.6.17-rc4 there is a regression causing
the netconsole messages which originate from netfilter to be truncated
right after the MAC addresses. For example, /var/log/messages on the
sending machine says:

May 31 09:28:11 porvoo kernel: IN=eth0 OUT= MAC=00:12:3f:85:9f:92:00:04:9a:a0:1d:d1:08:00 SRC=192.168.100.30 DST=172.17.1.113 LEN=60 TOS=0x00 PREC=0x00 TTL=54 ID=51496 DF PROTO=TCP SPT=50868 DPT=22 WINDOW=5840 RES=0x00 SYN URGP=0

but netconsole messages captured in /var/log/messages on the receiving
machine:

May 31 09:28:11 porvoo IN=eth0 OUT=
May 31 09:28:11 porvoo MAC=
May 31 09:28:11 porvoo 00:
May 31 09:28:11 porvoo 12:
May 31 09:28:11 porvoo 3f:
May 31 09:28:11 porvoo 85:
May 31 09:28:11 porvoo 9f:
May 31 09:28:11 porvoo 92:
May 31 09:28:11 porvoo 00:
May 31 09:28:11 porvoo 04:
May 31 09:28:11 porvoo 9a:
May 31 09:28:11 porvoo a0:
May 31 09:28:11 porvoo 1d:
May 31 09:28:11 porvoo d1:
May 31 09:28:11 porvoo 08:
May 31 09:28:11 porvoo 00
May 31 09:49:06 espoo -- MARK --

I ran a tcpdump on the sending machine to verify(?) what goes out but in
that case the 2.6.17-rc4 kernel starts to report "protocol 0000 is buggy":

[...]



The message means that there was recursion and netpoll fell back
to dev_queue_xmit This patch should fix the "protocol is buggy"
messages, netpoll didn't set skb->nh.raw. Please try if it also
makes the other problem go away.

"protocol 0000 is buggy" is gone. The other problem is still there.

--
Frank
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Relevant Pages

  • Re: 2.6.17-rc4: netfilter LOG messages truncated via NETCONSOLE
    ... has netconsole configured to send kernel messages to UDP port 514 ... the netconsole messages which originate from netfilter to be truncated ... May 31 09:28:11 porvoo MAC= ... I ran a tcpdump on the sending machine to verifywhat goes out but in ...
    (Linux-Kernel)
  • 2.6.17-rc4: netfilter LOG messages truncated via NETCONSOLE
    ... has netconsole configured to send kernel messages to UDP port 514 ... the netconsole messages which originate from netfilter to be truncated ... May 31 09:28:11 porvoo MAC= ... I ran a tcpdump on the sending machine to verifywhat goes out but in ...
    (Linux-Kernel)