Re: [REGRESSION] Kernel 3.6 drops network packets instead offorwarding

From: Eric Dumazet
Date: Sat Oct 06 2012 - 09:53:34 EST


On Sat, 2012-10-06 at 11:52 +0000, Chini, Georg (HP App Services) wrote:
> Hello,
>
> I have a network issue with kernel 3.6. My machine is set
> up as router and with 3.6 it sometimes silently drops reply
> packets instead of forwarding.
> Example tcpdump on the router for ping www.heise.de from a
> machine in my network (NAT is done elsewhere):
>
> 12:37:54.746627 IP 192.168.255.150 > 193.99.144.85: ICMP echo request, id 16414, seq 1, length 64 (eth0)
> 12:37:54.746681 IP 192.168.255.150 > 193.99.144.85: ICMP echo request, id 16414, seq 1, length 64 (GRE tunnel)
> 12:37:54.782195 IP 193.99.144.85 > 192.168.255.150: ICMP echo reply, id 16414, seq 1, length 64 (GRE tunnel)
> 12:37:54.782335 IP 193.99.144.85 > 192.168.255.150: ICMP echo reply, id 16414, seq 1, length 64 (eth0)
> 12:37:55.785974 IP 192.168.255.150 > 193.99.144.85: ICMP echo request, id 16416, seq 1, length 64 (eth0)
> 12:37:55.786023 IP 192.168.255.150 > 193.99.144.85: ICMP echo request, id 16416, seq 1, length 64 (GRE tunnel)
> 12:37:55.822529 IP 193.99.144.85 > 192.168.255.150: ICMP echo reply, id 16416, seq 1, length 64 (GRE tunnel)
> NO forwarded packet on eth0
>
> Then this goes on for an arbitrary period (between a few seconds and
> more then half an hour) and suddenly returns to normal. During that
> time no communication is possible between a host on my network and
> any external host. Connections from the router itself still work.
> With kernel 3.4.3 everything works fine. Had the same issue with
> -rc6 and -rc7.
>
> There are no messages in the logs. Any idea what might cause this
> or how I can debug it any further?
> I will supply more details on my setup if needed. Please CC me in
> your reply as I am not subscribed to the list.

Looks like the bug fixed by :

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=f4ef85bbda96324785097356336bc79cdd37db0a

(David Miller will send it to stable team shortly)



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