ipv6: addrconf: fix temp address generation after prefix deprecation

Browse source

When a router temporarily deprecates an IPv6 prefix (either by sending a
Router Advertisement with Preferred Lifetime = 0 or by letting the
lifetime expire) and later restores it, the kernel permanently loses its
ability to generate temporary privacy addresses (RFC 8981) for that
prefix.

This happens because the address worker attempts to generate a
replacement temporary address when the current one nears expiration. As
the base prefix is deprecated already, the generation fails after
marking the temporary address as already having spawned a replacement
(ifp->regen_count++).

When the router eventually restores the prefix, the temporary address
becomes active again. However, once it naturally expires, the address
worker sees this temporary address already tried to generate one and
skips the regeneration.

Fix the issue by resetting the regen_count check of the latest temp
address generated for the prefix updated by the incoming RA.

Reported-by: Łukasz Stelmach <steelman@post.pl>
Closes: https://lore.kernel.org/netdev/87340td30q.fsf%25steelman@post.pl/
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260523103811.3790-1-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Fernando Fernandez Mancera 2026-05-23 12:38:10 +02:00 • committed by Jakub Kicinski

parent 7599c13dbe

commit e20d8922aa

1 changed files with 9 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

10

net/ipv6/addrconf.c

View file