From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
To: John Nielsen <lists@jnielsen.net>, netdev@vger.kernel.org
Subject: Re: vxlan regression: multiple VXLANs on a single multicast group broken in kernel 4.1
Date: Tue, 25 Aug 2015 15:52:08 -0300 [thread overview]
Message-ID: <55DCB958.3080904@gmail.com> (raw)
In-Reply-To: <1F0A5B2B-5C6D-426F-91E9-A7A2F11A98A9@jnielsen.net>
Em 25-08-2015 14:35, John Nielsen escreveu:
> After updating the kernel on a KVM host, I discovered yesterday that I can no longer use more than one vxlan interface on a single multicast group/address. The interfaces can be created but only the first one may be brought up:
>
> # ip link add vx100 type vxlan id 100 group 239.0.0.1 dev eth0
> # ip link add vx200 type vxlan id 200 group 239.0.0.1 dev eth0
> # ip link set up dev vx100
> # ip link set up dev vx200
> RTNETLINK answers: Address already in use
>
> Using unique group addresses (one VNI per group) still works as expected. The problem is not present in kernel 4.0.5 but it is in kernel 4.1.0.
>
> I suspect (but have not verified) that the regression was caused by this commit:
> vxlan: Move socket initialization to within rtnl scope 56ef9c909b40483d2c8cb63fcbf83865f162d5ec
>
> https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/drivers/net/vxlan.c?id=56ef9c909b40483d2c8cb63fcbf83865f162d5ec
>
> I am working to verify that that is the culprit but I thought I’d see in the mean time if anyone else has encountered and/or fixed this, or can at least shed more light on the problem.
Yes that commit is the culprit. Previously it was ignoring igmp_join
errors, and now it's not but at the same time, it's trying to double
join that group on the socket that is reused.
Will try to cook a patch here, thanks for the report!
If you need a hack for now, just ignore vxlan_igmp_join() return value
at vxlan_open() and it should be fine.
Marcelo
next prev parent reply other threads:[~2015-08-25 18:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-25 17:35 vxlan regression: multiple VXLANs on a single multicast group broken in kernel 4.1 John Nielsen
2015-08-25 18:52 ` Marcelo Ricardo Leitner [this message]
2015-08-25 23:22 ` [PATCH net] vxlan: re-ignore EADDRINUSE from igmp_join Marcelo Ricardo Leitner
2015-08-25 23:25 ` David Miller
2015-09-01 21:02 ` John Nielsen
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