Re: [PATCH net 1/3] bpf: bpf_out_neigh_v4: Fix nd_tbl NULL dereference when IPv6 is disabled

From: Jakub Kicinski

Date: Mon Mar 02 2026 - 20:11:42 EST


On Mon, 2 Mar 2026 06:58:46 +0100 Daniel Borkmann wrote:
> > } else if (nh->nh_family == AF_INET6) {
> > + if (!ipv6_stub->nd_tbl) {
> > + rcu_read_unlock();
> > + goto out_drop;
> > + }
>
> Can we just completely get rid of allowing IPv6 as a module?
> So either its built-in or not available at all, and then we
> can get rid of the stub completely rather than adding checks
> in various places which also brings a small performance benefit
> of not having indirect calls in some places.

+1 fwiw, if someone complains we can revert it back in
feels like a complete waste of everyone's time to maintain it
https://lore.kernel.org/all/20260224180544.3c865751@xxxxxxxxxx/