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From: Ben Greear <greearb@candelatech•com>
To: Vladislav Yasevich <vyasevich@gmail•com>
Cc: Cong Wang <cwang@twopensource•com>,
	Hannes Frederic Sowa <hannes@stressinduktion•org>,
	Hongmei Li <duckcncn@gmail•com>, netdev <netdev@vger•kernel.org>
Subject: Re: IPv6 FIB related crash with MACVLANs in 3.9.11+ kernel.
Date: Mon, 13 Oct 2014 11:06:12 -0700	[thread overview]
Message-ID: <543C1494.4090602@candelatech.com> (raw)
In-Reply-To: <CAGCdqXHh6AvabW2JwQEK5NcnTuxw9eMdRwd+JvYZUYqyHW4K7Q@mail.gmail.com>

On 10/12/2014 04:42 AM, Vladislav Yasevich wrote:
> On Mon, Sep 29, 2014 at 5:24 PM, Ben Greear <greearb@candelatech•com> wrote:
>> On 09/29/2014 01:39 PM, Cong Wang wrote:
>>> On Mon, Sep 29, 2014 at 12:48 PM, Ben Greear <greearb@candelatech•com> wrote:
>>>>
>>>> We are going to be running up to 20 concurrent scripts that
>>>> will be dumping routes & ips, and configuring ip addresses
>>>> and routes during bringup.
>>>>
>>>> I don't have a simple stand-alone way to reproduce this,
>>>> but at least when we reported the problem is was very easy
>>>> for us to reproduce with our tool.
>>>>
>>>> Maybe 20 scripts running in parallel that randomly configured and dumped routes
>>>> and ip addresses on random interfaces would do the trick?
>>>>
>>>
>>> I think the most important question is why is this related with macvlan?
>>> IPv6 is L3 while macvlan pure L2, if this is a IPv6 routing bug, it should
>>> not be limited to macvlan.
>>
>> We saw it using mac-vlans on top of ixgbe.  Probably it can be reproduced
>> elsewhere, but since we had a good test case, we didn't bother trying lots
>> of other combinations.
>>
>> Just enabling some debug code caused the problem to be much harder
>> to reproduce, so it is probably some sort of race.  Maybe lots of mac-vlans
>> make it easier to hit.
>>
>>> What does your IPv6 routing table look like? And how do you configure those
>>> macvlan interfaces?
>>
>> Each interface would have it's own routing table, with at least as subnet
>> route.  I'm not sure we were adding a default gateway or not.
>>
>> The main routing table would also have some auto-created routes
>> I think.
>>
>> It is configured using 'ip' to add and dump routes.
>>
> 
> Ben
> 
> Just saw this thread.  Can you check if this commit makes a difference:
> commit 40b8fe45d1f094e3babe7b2dc2b71557ab71401d
> Author: Vlad Yasevich <vyasevich@gmail•com>
> Date:   Mon Sep 22 16:34:17 2014 -0400
> 
>     macvtap: Fix race between device delete and open.

We can retest this, but we do not use macvtap, and we have higher-priority
things to test at the moment, so might be a while.

Thanks,
Ben

> 
> Thanks
> -vlad
> 
>> Thanks,
>> Ben
>>
>> --
>> Ben Greear <greearb@candelatech•com>
>> Candela Technologies Inc  http://www.candelatech.com
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majordomo@vger•kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 


-- 
Ben Greear <greearb@candelatech•com>
Candela Technologies Inc  http://www.candelatech.com

      reply	other threads:[~2014-10-13 18:06 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-03 20:37 IPv6 FIB related crash with MACVLANs in 3.9.11+ kernel Ben Greear
2014-02-03 22:03 ` Hannes Frederic Sowa
2014-02-03 22:06   ` Ben Greear
2014-02-08 16:43     ` Ben Greear
2014-02-08 17:23       ` Hannes Frederic Sowa
2014-09-25 22:24         ` Hongmei Li
2014-09-28 12:11           ` Hannes Frederic Sowa
2014-09-29 18:15             ` Hongmei Li
2014-09-29 18:44               ` Ben Greear
2014-09-29 19:03                 ` Hannes Frederic Sowa
2014-09-29 19:48                   ` Ben Greear
2014-09-29 20:39                     ` Cong Wang
2014-09-29 21:24                       ` Ben Greear
2014-10-12 11:42                         ` Vladislav Yasevich
2014-10-13 18:06                           ` Ben Greear [this message]

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