Re: [PATCH net-next v3] selftests: net: add IPv4 and IPv6 address order check

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

On 9/14/26 8:58 AM, Martin Jabůrek wrote:
> Introduce the following new tests: `ipv4_verify_same_scope_addr_order`,
> `ipv4_verify_inter_scope_addr_order`, `ipv6_verify_same_scope_addr_order`,
> `ipv6_verify_inter_scope_addr_order` to check the ordering of a
> set of IP addresses after being inserted.
> 
> The implementations of these protocols are inconsistent
> in regard to address ordering. IPv4 addresses stay in the
> same order as inserted while IPv6 addresses appear in
> reverse order. This inconsistency has prompted attempts
> to unify the ordering, so both protocols act the same
> (as IPv4). This however caused user-space regressions in
> certain applications, which relied on the order as it
> was prior to the change (particularly NetworkManager).
> A similar inconsistency occurs when inserting different
> scope addresses, where IPv4 puts link local ones before global
> and IPv6 does the opposite. Attempts were already made
> to unify this also, risking further regressions.
> 
> The addition of these tests aims to consolidate current
> behaviour to prevent regressions in the future.
> The expected behaviour is the initial one, where each
> protocol acts differently. The same goes for inter scope
> addresses.
> 
> Conversations detailing the decision processes for creating
> these tests are linked below.
> 
> Link: https://lore.kernel.org/netdev/20260521135310.GC977@cmadams.net/
> Link: https://lore.kernel.org/netdev/20260529112357.5079-1-fmancera@suse.de/
> Link: https://lore.kernel.org/netdev/20260721090114.GA2510713@shredder/
> Suggested-by: Fernando Fernandez Mancera <fmancera@suse.de>
> Signed-off-by: Martin Jabůrek <martin.jaburek@suse.com>
The comments are a bit verbose IMHO but given that this already caused 
confusion it is likely to have it well documented on the tests.

Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>