Re: [PATCH 00/10 net-next v3] Convert CONFIG_IPV6 to built-in and remove stubs

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

On 3/17/26 8:49 PM, Jakub Kicinski wrote:
> On Tue, 17 Mar 2026 15:00:56 +0100 Fernando Fernandez Mancera wrote:
>> Historically, the Linux kernel has supported compiling the IPv6 stack as
>> a loadable module. While this made sense in the early days of IPv6
>> adoption, modern deployments and distributions overwhelmingly either
>> build IPv6 directly into the kernel (CONFIG_IPV6=y) or disable it
>> entirely (CONFIG_IPV6=n). The modular IPv6 use-case offers image size
>> and memory savings for specific setups, this benefit is outweighed by
>> the architectural burden it imposes on the subsystems on implementation
>> and maintenance.
> 
> Hi Fernando,
> 
> NIPA flags a few failures, still:
> 
> https://netdev.bots.linux.dev/contest.html?pw-n=0&branch=net-next-2026-03-17--18-00&pw-n=0&pass=0
> 

Hi Jakub,

This is test is applying the series in top of bpf tree which has this 
commit 
https://github.com/kernel-patches/bpf/commit/972787479ee73006fddb5e59ab5c8e733810ff42

AFAICS, net-next tree do not have it yet. I do not think I can do much 
about it for now. Will wait until they are merged and rebase in top of it.

Thanks,
Fernando.

> See stderr for stack trace. The BPF build issue seems to be:
> 
>    ../net/bpf/test_run.c:1160:8: error: use of undeclared identifier 'ipv6_bpf_stub'
>     1160 |                 if (!ipv6_bpf_stub) {
>          |                      ^~~~~~~~~~~~~
>    1 error generated.
>    make[5]: *** [../scripts/Makefile.build:289: net/bpf/test_run.o] Error 1
>    make[4]: *** [../scripts/Makefile.build:546: net/bpf] Error 2
>    make[4]: *** Waiting for unfinished jobs....