Messages in this thread | | | From | Maciej Rutecki <> | Subject | Re: IPv6 flapping with kernel 3.3 (regression from 3.2.9) | Date | Sun, 25 Mar 2012 08:43:44 +0200 |
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On czwartek, 22 marca 2012 o 08:34:28 Marc Haber wrote: > Hi, > > I have a host which has IPv6 misbehaving when running with Linux 3.3. > It is flawlessly working with Linux 3.2.9. > > The host > - is running Debian stable (x64_64) with a few locally built and/or > backported packages, including the kernel. > - has native IPv6 connectivity on eth0 > - is not doing SLAAC on eth0, both IP address (from 2a01/16) and > default gateway (fe80::1) are statically configured > - is running a handful of VMs using KVM/libvirt > - has IPv6 forwarding enabled > - does IPv4 NAT > - has a handful of iptables rules, both for v4 and v6. ICMP and ICMPv6 > are fully open > > - the gateway is not under my control > - the VMs are either bridged to br0 or to br1 > - both br0 and br1 have an IPv6 /64 and radvd running to provide IPv6 > to the VMs > > This setup is unique in my machine list, my other machines either are > no KVM hosts or do only have IPv6 tunneled. > > When I run the box with kernel 3.3, it drops off the IPv6 network > every few minutes and is not responding to pings any more. This state > stays like 30 seconds to a minute and then IPv6 resumes. It looks to > me that the box does not lose its default route though. Once in a > while, I see "fe80::1 dev eth0 router FAILED" in the ip neigh output. > > Running a continuous ping in either direction doesn't seem to help. > > Booting the box back to 3.2.9 immediately fixes the issue. > > I have not yet re-tried going back to 3.3 since a few of the VMs are > too important to reboot again today. I tried running tcpdump on eth0 > over night but hit br1 instead, so I don't have any packet dumps to > show. > > I guess that something goes wrong with neighbor detection regarding > the IPv6 gateway. > > Was there a relevant change between 3.2.9 and 3.3? Where do I look for > the issue? > > Greetings > Marc
I created a Bugzilla entry at https://bugzilla.kernel.org/show_bug.cgi?id=42991 for your bug/regression report, please add your address to the CC list in there, thanks!
-- Maciej Rutecki http://www.mrutecki.pl
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