netdev - Re: [PATCH net-next v2] ipv6: clean up routes when manually removing address with a lifetime

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Message-ID: <aRXMnmTapb9VNbc4@shredder>
Date: Thu, 13 Nov 2025 14:18:38 +0200
From: Ido Schimmel <idosch@...dia.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: davem@...emloft.net, netdev@...r.kernel.org, edumazet@...gle.com,
	pabeni@...hat.com, andrew+netdev@...n.ch, horms@...nel.org,
	dsahern@...nel.org
Subject: Re: [PATCH net-next v2] ipv6: clean up routes when manually removing
 address with a lifetime

On Wed, Nov 12, 2025 at 07:17:00PM -0800, Jakub Kicinski wrote:
> When an IPv6 address with a finite lifetime (configured with valid_lft
> and preferred_lft) is manually deleted, the kernel does not clean up the
> associated prefix route. This results in orphaned routes (marked "proto
> kernel") remaining in the routing table even after their corresponding
> address has been deleted.
> 
> This is particularly problematic on networks using combination of SLAAC
> and bridges.
> 
> 1. Machine comes up and performs RA on eth0.
> 2. User creates a bridge
>    - does an ip -6 addr flush dev eth0;
>    - adds the eth0 under the bridge.
> 3. SLAAC happens on br0.
> 
> Even tho the address has "moved" to br0 there will still be a route
> pointing to eth0, but eth0 is not usable for IP any more.
> 
> Signed-off-by: Jakub Kicinski <kuba@...nel.org>

Reviewed-by: Ido Schimmel <idosch@...dia.com>