Comment 7 for bug 1120617

I'm now running 13.04-to-be Raring Ringtail daily version (so 2013-02-12), with Linux 3.8.0-6-generic, and ... exactly the same behaviour:

After connecting to the Wifi, two public IPv6 address appear on the wlan0, and then disappear within a second or so. And dmesg says:

[ 280.076792] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:1dc0:6e87:d414:43ad detected!
[ 280.485760] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:1af4:6aff:fe9c:ced4 detected!
[ 280.894809] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:94b4:2566:5e86:dfc2 detected!
[ 281.099125] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:6d25:db13:c7bd:e28d detected!
[ 281.099132] IPv6: ipv6_create_tempaddr: regeneration time exceeded - disabled temporary address support
[ 433.114565] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:1af4:6aff:fe9c:ced4 detected!
[ 589.423402] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:1af4:6aff:fe9c:ced4 detected!
[ 773.027247] IPv6: wlan0: IPv6 duplicate address 2a00:cd8:blabla:1af4:6aff:fe9c:ced4 detected!

So, my conclusion: NOT fixed in upstream. I will add the tag 'kernel-bug-exists-upstream'.

FWIW: I did

sudo sysctl net.ipv6.conf.wlan0.accept_dad=0

and after a few minutes, one public IPv6 address (the MAC-based one) appeared on wlan0. So ... same behaviour again.

After disabling Wifi (but still net.ipv6.conf.wlan0.accept_dad=0) and enabling it again, two IPv6 addresses appeared: the MAC-based one, and another one (so: with privacy extensions).

ubuntu@ubuntu:~$ uname -a
Linux ubuntu 3.8.0-6-generic #11-Ubuntu SMP Mon Feb 11 16:02:49 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

ubuntu@ubuntu:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Raring Ringtail (development branch)
Release: 13.04
Codename: raring
ubuntu@ubuntu:~$