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

From: Jakub Kicinski <[email-masked]>
Date: Tue, 17 Mar 2026 12:49:04 -0700

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

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....
-- 
pw-bot: cr