On 10/03/12 04:10, David Miller wrote:

From: Julian Anastasov <ja@ssi.bg>
Date: Wed, 3 Oct 2012 02:24:53 +0300 (EEST)

quoted

	Can it be a problem related to fib_info reuse
from different routes. For example, when local IP address
is created for subnet we have:

broadcast 192.168.0.255 dev DEV  proto kernel  scope link  src 192.168.0.1
192.168.0.0/24 dev DEV  proto kernel  scope link  src 192.168.0.1
local 192.168.0.1 dev DEV  proto kernel  scope host  src 192.168.0.1

	The "dev DEV  proto kernel  scope link  src 192.168.0.1" is
a reused fib_info structure where we put cached routes.
The result can be same fib_info for 192.168.0.255 and
192.168.0.0/24. RTN_BROADCAST is cached only for input
routes. Incoming broadcast to 192.168.0.255 can be cached
and can cause problems for traffic forwarded to 192.168.0.0/24.
So, this patch should solve the problem because it
separates the broadcast from unicast traffic.

Now I understand the problem.

I think the way to fix this is to add cfg->fc_type as another
thing that fib_info objects are key'd by.

I think it also would fix your obscure output multicast case too.

I've seen the discussion about whether Eric's patch is OK or not, but 
thought I'd give it a spin anyway. It applies to 3.6.0 with some fuzz, 
but I can confirm that with the patch applied I can now ping my router 
and browse the internet from a KVM client, so the Eric's diagnosis 
matches the problem I reported.

However, after closing the client, I got an oops. I've taken a 
photograph of the screen and uploaded it to 
http://i714.photobucket.com/albums/ww149/chris2553/IMAG0059.jpg. As it's 
not the final patch, this may be a red herring, but I thought I'd better 
give a heads up anyway.

Chris