Re: [BUG] some temporary IPv6 address don't get regenerated

[Fernando Fernandez Mancera <fmancera@suse.de>]

On 4/17/26 5:23 PM, Łukasz Stelmach wrote:
> Hi,
> 
> Apparently, something in addrconf.c can go wrong and a temporary
> addresses may not get regenerated leaving users who wish to use them
> with only the stable ones. Below, 2a01:110f:4321:1002:abcc:78d7:2055:94ec
> while still valid is not preferred anymore. Even if it's not the only
> global temporary address it is the only usable to contact hosts on the
> Internet because the other temporary addresses are ULA.
> 

Hi,

I managed to reproduce this, it took me quite some time. It looks like a 
race condition somewhere. I am working on a fix and I will add a 
selftest covering this too.

Ideally, I will send a fix this week. I am now checking if this was 
introduced recently or was always broken.

> Neither received RAs nor adding and removing an address manually (one
> with a different prefix unrelated to these below) which as far as I
> understand, should trigger address maintenance code.
> 

Yup, same situation here.

Thanks,
Fernando.

> I noticed this phenomenon once or twice before. It seems to be very
> rare, yet quite undesirable I'd say. What might have triggered it today
> is a reboot of my router and (possible?) change in lifetime values it
> announced.
> 
> Even stranger is that there is a preferred fd89:: (ULA), but not 2a01::.
> 
> accept_ra as well as use_tempaddr are set to 2.
> 
> Of course, this ma be get fixed by a suspend/resume (no, it may not) or
> manual ifdown/ifup (of course it helped), but nevertheless I thought it
> was worth reporting.
> 
> --8<---------------cut here---------------start------------->8---
> 107: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
>      link/ether b8:ca:3a:d4:1e:97 brd ff:ff:ff:ff:ff:ff
>      inet 192.168.2.122/24 brd 192.168.2.255 scope global dynamic bond0
>         valid_lft 165585sec preferred_lft 165585sec
> 
>      inet6 fd89:82bb:420:2:cab3:d2d6:aeeb:e250/64 scope global temporary dynamic
>         valid_lft 597079sec preferred_lft 78177sec
> 
>      inet6 2a01:110f:4321:1002:abcc:78d7:2055:94ec/64 scope global temporary deprecated dynamic
>         valid_lft 60815sec preferred_lft 0sec
> 
>      inet6 2a01:110f:4321:1002:abac:3aff:fed4:beef/64 scope global dynamic mngtmpaddr proto kernel_ra
>         valid_lft 60815sec preferred_lft 60815sec
> 
>      inet6 fd89:82bb:420:2:24bf:fe8f:5c9c:c753/64 scope global temporary deprecated dynamic
>         valid_lft 511186sec preferred_lft 0sec
> 
>      inet6 fd89:82bb:420:2:abac:3aff:fed4:beef/64 scope global dynamic mngtmpaddr proto kernel_ra
>         valid_lft 2591805sec preferred_lft 604605sec
> 
>      inet6 fe80::abac:3aff:fed4:beef/64 scope link proto kernel_ll
>         valid_lft forever preferred_lft forever
> --8<---------------cut here---------------end--------------->8---
>