From: Jakub Kicinski <kuba@kernel.org>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: "Fernando Fernandez Mancera" <fmancera@suse.de>,
"David Ahern" <dsahern@kernel.org>,
"Ricardo B. Marlière" <rbm@suse.com>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"John Fastabend" <john.fastabend@gmail.com>,
"Stanislav Fomichev" <sdf@fomichev.me>,
"Alexei Starovoitov" <ast@kernel.org>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Song Liu" <song@kernel.org>,
"Yonghong Song" <yonghong.song@linux.dev>,
"KP Singh" <kpsingh@kernel.org>, "Hao Luo" <haoluo@google.com>,
"Jiri Olsa" <jolsa@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Jay Vosburgh" <jv@jvosburgh.net>,
"Andrew Lunn" <andrew+netdev@lunn.ch>,
"Hangbin Liu" <liuhangbin@gmail.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net 1/3] bpf: bpf_out_neigh_v4: Fix nd_tbl NULL dereference when IPv6 is disabled
Date: Wed, 4 Mar 2026 17:43:27 -0800 [thread overview]
Message-ID: <20260304174327.0a48ff45@kernel.org> (raw)
In-Reply-To: <525dab04-4e64-49cf-94d9-12084e146b80@iogearbox.net>
On Thu, 5 Mar 2026 02:34:00 +0100 Daniel Borkmann wrote:
> > Maybe I am missing something here, but I believe this won't solve
> > the problem. Even if ipv6 is built-in, it should be possible to
> > pass ipv6.disable=1 during boot and therefore nd_tbl would still be
> > uninitialized, not NULL tho.
>
> I presume you mean disable_ipv6_mod which then bails out during the module
> load process without error, right? It could be deprecated with a warning so
> that it turns into a no-op:
I believe disabling ipv6 may be legit. Some admins on ipv4 networks may
be paranoid and not want to allow any ipv6 traffic if their "firewalls"
can only understand IPv6? This is just a guess on my side, but I'm less
confident of deprecating the disable knob than =m. I'd be happy if I'm
wrong.
To answer the earlier question -- I would prefer to take the fixes now
and make IPv6 bool in net-next, feels like too big of a change for rc3
:(
next prev parent reply other threads:[~2026-03-05 1:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-28 17:46 [PATCH net 0/3] {net,bpf}: nd_tbl fixes for when ipv6.disable=1 Ricardo B. Marlière
2026-02-28 17:46 ` [PATCH net 1/3] bpf: bpf_out_neigh_v4: Fix nd_tbl NULL dereference when IPv6 is disabled Ricardo B. Marlière
2026-03-02 5:58 ` Daniel Borkmann
2026-03-03 1:11 ` Jakub Kicinski
2026-03-03 11:18 ` Fernando Fernandez Mancera
2026-03-04 4:49 ` Daniel Borkmann
2026-03-04 15:49 ` David Ahern
2026-03-04 16:13 ` Fernando Fernandez Mancera
2026-03-05 1:34 ` Daniel Borkmann
2026-03-05 1:43 ` Jakub Kicinski [this message]
2026-03-05 1:59 ` Daniel Borkmann
2026-03-05 2:50 ` Jakub Kicinski
2026-03-05 12:42 ` Ricardo B. Marlière
2026-02-28 17:46 ` [PATCH net 2/3] bpf: bpf_out_neigh_v6: " Ricardo B. Marlière
2026-02-28 17:46 ` [PATCH net 3/3] net: bonding: " Ricardo B. Marlière
2026-03-02 1:25 ` Hangbin Liu
2026-03-01 18:29 ` [PATCH net 0/3] {net,bpf}: nd_tbl fixes for when ipv6.disable=1 Fernando Fernandez Mancera
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