netdev - Re: possible issue between bridge igmp/multicast handling & bnx2x on kernel 2.6.34 and >

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Message-ID: <4D26EDA4.7060502@univ-nantes.fr>
Date:	Fri, 07 Jan 2011 11:40:36 +0100
From:	Yann Dupont <Yann.Dupont@...v-nantes.fr>
To:	netdev@...r.kernel.org
Subject: Re: possible issue between bridge igmp/multicast  handling & bnx2x
 on kernel 2.6.34 and >

Le 04/01/2011 14:40, Yann Dupont a écrit :
...
> We just added BCM57711 10G cards (bnx2x driver) on our blade servers 
> (connected to 10G Power Connect M8024).
> Since then, we are experiencing random lost of packets.
>
> Symptom : packets are lost on some vlans for a few seconds, then 
> things go back to normal (and stops again a few minutes later)
>

As I didn't had answer so far , I digged a little more and captured more 
packets.
I just noticed that an event trigger that problem : IPv6 neighbor 
discovery packet .

This is , of course, a multicast packet.

Just saw that 2.6.36.3 should include this fix :

> From: David Stevens<dlstevens@...ibm.com>
>
> [ Upstream commit 04bdf0c9a451863e50fff627713a900a2cabb998 ]
>
> This patch fixes a missing ntohs() for bridge IPv6 multicast snooping.
But in fact , I just tested, and this doesn't cure the problem :(

This bug
- only occurs with bnx2x with tagged vlans, attached to bridges. Other 
interfaces (bnx2 , for exemple) works fine. bnx2x without bridges works 
fine.
- only happens when bridge is compiled with CONFIG_BRIDGE_IGMP_SNOOPING 
(default setting)
- is triggered by IPv6 neighbor discovery packet. Just after that 
packet, others packets are discarded for some time.
- packets originating from same vlans are not affected, only packets 
previously routed are discarded. Examinating those packets, I don't 
undersand why, apart TTL (and mac address), they seems similar .
- has origin circa 2.6.33 :
fe2d7c70b747d5d968f4e8fa210676d49d40059 is the first bad commit
commit 3fe2d7c70b747d5d968f4e8fa210676d49d40059
Author: Herbert Xu <herbert@...dor.apana.org.au>
Date:   Sun Feb 28 00:49:38 2010 -0800

     bridge: Add multicast start/stop hooks

     This patch hooks up the bridge start/stop and add/delete/disable
     port functions to the new multicast module.

     Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
     Signed-off-by: David S. Miller <davem@...emloft.net>



What can I do to help fixing this bug ?
regards,

-- 
Yann Dupont - Service IRTS, DSI Université de Nantes
Tel : 02.53.48.49.20 - Mail/Jabber : Yann.Dupont@...v-nantes.fr

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