Subject: Re: bridge not getting ip since 3.11.5 and 3.4.66

From: Vlad Yasevich <[email-masked]>
Date: Tue, 26 Nov 2013 10:25:23 -0500

On 11/26/2013 08:27 AM, Mark Trompell wrote:
> Answering my own mail again and even top posting, sorry, but makes
> more sense to me in that case).
> I reverted bridge related patches from 3.11.5 and it boils down to
> commit 0e308361d7ca0bf8b23fd472b90aae0fb10a1c32
> Author: Herbert Xu <[email-masked]>
> Date:   Thu Sep 12 17:12:05 2013 +1000
> 
>     bridge: Clamp forward_delay when enabling STP
> 
>     [ Upstream commit be4f154d5ef0ca147ab6bcd38857a774133f5450 ]
> 
>     At some point limits were added to forward_delay.  However, the
>     limits are only enforced when STP is enabled.  This created a
>     scenario where you could have a value outside the allowed range
>     while STP is disabled, which then stuck around even after STP
>     is enabled.
> 
>     This patch fixes this by clamping the value when we enable STP.
> 
>     I had to move the locking around a bit to ensure that there is
>     no window where someone could insert a value outside the range
>     while we're in the middle of enabling STP.
> 
> Causing the issue for me. Reverting that patch and br0 comes up again
> and gets an ip.

yes, that patch introduced a bug where we always used the
max_forward delay value.

you have 2 options:
 1) disable STP.  Since you are just running VMs and you have a single
    physical connection on the bridge, you can safely disable STP since
    your system is a leaf node.

 2) Get the latest stable kernel.  The bug has been fixed there.

-vlad

> 
> On Tue, Nov 12, 2013 at 11:57 AM, Mark Trompell <[email-masked]> wrote:
>> On Mon, Nov 11, 2013 at 1:52 PM, Mark Trompell <[email-masked]> wrote:
>>> On Mon, Nov 11, 2013 at 12:07 PM, Veaceslav Falico <[email-masked]> wrote:
>>>> On Mon, Nov 11, 2013 at 11:29 AM, Mark Trompell <[email-masked]> wrote:
>>>>> my bridge br0 doesn't get an ip from dhcp anymore after 3.11.5 and 3.4.66,
>>>>> What information would be helpful and required to find out what's going wrong.
>>>>
>>>> CC netdev
>>>>
>>>> First thing would be to provide the network scheme. Do you use vlans?
>>>> Which network
>>>> cards/drivers are you using? Do you use some kind of virtualization?
>>>> Is bonding involved?
>>>>
>>> Actually this is my desktop machine using kvm for a virtual machine
>>> that uses eth0 which is connected to the bridge
>>> which is used as interface for the host.
>>>
>>> $ ip addr
>>> 2. eth0: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc pfifo_fast
>>> master br0 qlen 1000
>>> ...
>>> 3. br0: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc noqueue
>>> ...
>>>
>>> Anything else?
>>
>> Okay more about my hardware and configuration:
>> from lspci:
>> 00:19.0 Ethernet controller: Intel Corporation 82579V Gigabit Network
>> Connection (rev 04)
>>
>> /etc/sysconfig/network-scripts/ifcfg-br0
>> DEVICE=br0
>> ONBOOT=yes
>> MACADDR=00:19:99:ac:b3:24
>> TYPE=Bridge
>> BOOTPROTO=dhcp
>> STP=on
>> NM_CONTROLLED=no
>> DELAY=0
>>
>> /etc/sysconfig/network-scripts/ifcfg-eth0
>> DEVICE=eth0
>> HWADDR=00:19:99:cd:a5:e6
>> #BOOTPROTO=dhcp
>> ONBOOT=yes
>> BRIDGE=br0
>> TYPE=Ethernet
>> NM_CONTROLLED=no
>>
>>
>>> Greetings
>>> Mark
> 
> 
>