netdev - Re: [BUG] bonded interfaces drop bpdu (stp) frames

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Date:   Thu, 12 Jul 2018 18:37:15 +0200
From:   Michal Soltys <soltys@....info>
To:     Jay Vosburgh <jay.vosburgh@...onical.com>,
        Mahesh Bandewar (महेश बंडेवार) <maheshb@...gle.com>
Cc:     linux-netdev <netdev@...r.kernel.org>
Subject: Re: [BUG] bonded interfaces drop bpdu (stp) frames

On 07/12/2018 04:51 PM, Jay Vosburgh wrote:
> Mahesh Bandewar (महेश बंडेवार) wrote:
> 
>> On Wed, Jul 11, 2018 at 3:23 PM, Michal Soltys <soltys@....info> wrote:
>>>
>>> Hi,
>>>
>>> As weird as that sounds, this is what I observed today after bumping
>>> kernel version. I have a setup where 2 bonds are attached to linux
>>> bridge and physically are connected to two switches doing MSTP (and
>>> linux bridge is just passing them).
>>>
>>> Initially I suspected some changes related to bridge code - but quick
>>> peek at the code showed nothing suspicious - and the part of it that
>>> explicitly passes stp frames if stp is not enabled has seen little
>>> changes (e.g. per-port group_fwd_mask added recently). Furthermore - if
>>> regular non-bonded interfaces are attached everything works fine.
>>>
>>> Just to be sure I detached the bond (802.3ad mode) and checked it with
>>> simple tcpdump (ether proto \\stp) - and indeed no hello packets were
>>> there (with them being present just fine on active enslaved interface,
>>> or on the bond device in earlier kernels).
>>>
>>> If time permits I'll bisect tommorow to pinpoint the commit, but from
>>> quick todays test - 4.9.x is working fine, while 4.16.16 (tested on
>>> debian) and 4.17.3 (tested on archlinux) are failing.
>>>
>>> Unless this is already a known issue (or you have any suggestions what
>>> could be responsible).
>>>
>> I believe these are link-local-multicast messages and sometime back a
>> change went into to not pass those frames to the bonding master. This
>> could be the side effect of that.
> 
> 	Mahesh, I suspect you're thinking of:
> 
> commit b89f04c61efe3b7756434d693b9203cc0cce002e
> Author: Chonggang Li <chonggangli@...gle.com>
> Date:   Sun Apr 16 12:02:18 2017 -0700
> 
>      bonding: deliver link-local packets with skb->dev set to link that packets arrived on
> 
> 	Michal, are you able to revert this patch and test?
> 
> 	-J
> 
> ---
> 	-Jay Vosburgh, jay.vosburgh@...onical.com
> 


Just tested - yes, reverting that patch solves the issues.