Hello,

On Sat, Nov 15, 2025 at 10:59:38AM +0100, Fernando Fernandez Mancera wrote:

When an IPv6 Router Advertisement (RA) is received for a prefix, the kernel creates the corresponding on-link route with flags RTF_ADDRCONF and RTF_PREFIX_RT configured and RTF_EXPIRES if lifetime is set.

If later a user configures a static IPv6 address on the same prefix the kernel clears the RTF_EXPIRES flag but it doesn't clear the RTF_ADDRCONF and RTF_PREFIX_RT. When the next RA for that prefix is received, the kernel sees the route as RA-learned and wrongly configures back the lifetime. This is problematic because if the route expires, the static address won't have the corresponding on-link route.

This fix clears the RTF_ADDRCONF and RTF_PREFIX_RT flags preventing that the lifetime is configured when the next RA arrives. If the static address is deleted, the route becomes RA-learned again.

Fixes: 14ef37b6d00e ("ipv6: fix route lookup in addrconf_prefix_rcv()") Reported-by: Garri Djavadyan g.djavadyan@gmail.com Closes: https://lore.kernel.org/netdev/ba807d39aca5b4dcf395cc11dca61a130a52cfd3.came... Signed-off-by: Fernando Fernandez Mancera fmancera@suse.de

this commit is in the mainline now as f72514b3c5698e4b900b25345e09f9ed33123de6 and is supposed to fix https://bugs.debian.org/1117959.

I would have expected this to get backported to stable (here: 6.12.x), but it's not in the list for 6.12.62-rc1[1].

Can we please have this patch backported?

[1] https://lore.kernel.org/all/20251210072948.125620687@linuxfoundation.org/

Thanks Uwe