[PATCH 00/10 net-next] Convert CONFIG_IPV6 to built-in and remove stubs
From: Fernando Fernandez Mancera
Date: Sun Mar 08 2026 - 22:20:47 EST
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 provides little to
no practical benefit today.
To allow core networking, BPF, Netfilter, and various device drivers to
safely interact with a potentially unloaded IPv6 module, the kernel
relies on indirect call structures like ipv6_stub, ipv6_bpf_stub, and
nf_ipv6_ops, along with dynamic RCU registrations for things like ICMPv6
senders.
This patch series addresses this by changing CONFIG_IPV6 from a tristate
to a boolean, enforcing that IPv6 is either built-in or disabled. This
allows us to completely rip out the stub infrastructures and safely
replace them with direct function calls.
All the patches has been independently build tested. With allmodconfig
and allmodconfig + CONFIG_IPV6=n. In addition, IPv6 core network
selftest has been run against them.
The series applied as a whole as been tested with allyesconfig and also
allyesconfig + CONFIG_IPV6=n but not all patches has been independently
tested this way.
This will like need to wait for [1] and [2] to be applied to avoid
conflicts from net tree and rebased in top of them.
[1] https://lore.kernel.org/netdev/20260307-net-nd_tbl_fixes-v4-0-e2677e85628c@xxxxxxxx/
[2] https://lore.kernel.org/netdev/20260308032304.1841198-1-kuniyu@xxxxxxxxxx/
Fernando Fernandez Mancera (10):
ipv6: convert CONFIG_IPV6 to built-in only and clean up Kconfigs
ipv6: replace IS_BUILTIN(CONFIG_IPV6) with IS_ENABLED(CONFIG_IPV6)
ipv6: remove dynamic ICMPv6 sender registration infrastructure
ipv6: prepare headers for ipv6_stub removal
drivers: net: drop ipv6_stub usage and use direct function calls
ipv4: drop ipv6_stub usage and use direct function calls
net: convert remaining ipv6_stub users to direct function calls
bpf: remove ipv6_bpf_stub completely and use direct function calls
ipv6: remove ipv6_stub infrastructure completely
netfilter: remove nf_ipv6_ops and use direct function calls
arch/arm64/configs/defconfig | 2 +-
arch/m68k/configs/amiga_defconfig | 2 +-
arch/m68k/configs/apollo_defconfig | 2 +-
arch/m68k/configs/atari_defconfig | 2 +-
arch/m68k/configs/bvme6000_defconfig | 2 +-
arch/m68k/configs/hp300_defconfig | 2 +-
arch/m68k/configs/mac_defconfig | 2 +-
arch/m68k/configs/multi_defconfig | 2 +-
arch/m68k/configs/mvme147_defconfig | 2 +-
arch/m68k/configs/mvme16x_defconfig | 2 +-
arch/m68k/configs/q40_defconfig | 2 +-
arch/m68k/configs/sun3_defconfig | 2 +-
arch/m68k/configs/sun3x_defconfig | 2 +-
drivers/infiniband/Kconfig | 1 -
drivers/infiniband/core/addr.c | 3 +-
drivers/infiniband/hw/ocrdma/Kconfig | 2 +-
drivers/infiniband/sw/rxe/rxe_net.c | 6 +-
drivers/infiniband/ulp/ipoib/Kconfig | 2 +-
drivers/net/Kconfig | 9 --
drivers/net/ethernet/broadcom/Kconfig | 2 +-
drivers/net/ethernet/chelsio/Kconfig | 2 +-
.../mellanox/mlx5/core/en/rep/neigh.c | 11 +-
.../ethernet/mellanox/mlx5/core/en/tc_tun.c | 3 +-
.../mellanox/mlx5/core/en/tc_tun_encap.c | 2 +-
.../mellanox/mlx5/core/en_accel/ipsec.c | 1 -
.../net/ethernet/mellanox/mlx5/core/en_rep.c | 1 -
.../net/ethernet/mellanox/mlx5/core/en_tc.c | 1 -
drivers/net/ethernet/mellanox/mlxsw/Kconfig | 1 -
.../ethernet/mellanox/mlxsw/spectrum_router.c | 8 +-
.../ethernet/mellanox/mlxsw/spectrum_span.c | 2 +-
drivers/net/ethernet/netronome/Kconfig | 1 -
.../ethernet/netronome/nfp/flower/action.c | 2 +-
.../netronome/nfp/flower/tunnel_conf.c | 9 +-
drivers/net/ethernet/sfc/tc_counters.c | 2 +-
drivers/net/ethernet/sfc/tc_encap_actions.c | 5 +-
drivers/net/geneve.c | 1 -
drivers/net/gtp.c | 2 +-
drivers/net/ovpn/peer.c | 3 +-
drivers/net/ovpn/udp.c | 3 +-
drivers/net/usb/cdc_mbim.c | 17 +--
drivers/net/vrf.c | 2 +-
drivers/net/vxlan/vxlan_core.c | 11 +-
drivers/net/vxlan/vxlan_multicast.c | 6 +-
drivers/net/wireguard/socket.c | 3 +-
drivers/net/wireless/intel/ipw2x00/ipw2100.c | 2 +-
drivers/scsi/bnx2fc/Kconfig | 1 -
drivers/scsi/bnx2i/Kconfig | 1 -
drivers/scsi/cxgbi/cxgb3i/Kconfig | 2 +-
drivers/scsi/cxgbi/cxgb4i/Kconfig | 2 +-
fs/dlm/Kconfig | 2 +-
fs/gfs2/Kconfig | 2 +-
include/linux/icmpv6.h | 26 +----
include/linux/indirect_call_wrapper.h | 2 +-
include/linux/netfilter_ipv6.h | 102 ++----------------
include/net/ip.h | 5 -
include/net/ip6_fib.h | 33 +++++-
include/net/ip6_route.h | 25 +++++
include/net/ipv6.h | 12 +++
include/net/ipv6_stubs.h | 102 ------------------
include/net/ndisc.h | 39 +++----
include/net/udp_tunnel.h | 3 +-
net/bridge/Kconfig | 1 -
net/bridge/br_arp_nd_proxy.c | 3 +-
net/bridge/br_netfilter_hooks.c | 12 +--
net/bridge/br_netfilter_ipv6.c | 7 +-
net/core/filter.c | 70 ++++++------
net/core/lwt_bpf.c | 10 +-
net/ieee802154/6lowpan/tx.c | 2 +-
net/ipv4/Kconfig | 9 +-
net/ipv4/fib_semantics.c | 11 +-
net/ipv4/icmp.c | 2 +-
net/ipv4/nexthop.c | 21 ++--
net/ipv4/route.c | 2 +-
net/ipv4/udp.c | 7 +-
net/ipv6/Kconfig | 6 +-
net/ipv6/addrconf.c | 10 +-
net/ipv6/addrconf_core.c | 91 ----------------
net/ipv6/af_inet6.c | 69 ++----------
net/ipv6/icmp.c | 6 --
net/ipv6/ip6_fib.c | 10 +-
net/ipv6/ip6_icmp.c | 46 +-------
net/ipv6/ip6_offload.c | 4 +-
net/ipv6/ip6_output.c | 5 +-
net/ipv6/ip6_udp_tunnel.c | 3 +-
net/ipv6/ndisc.c | 35 +++---
net/ipv6/netfilter.c | 48 ---------
net/ipv6/route.c | 13 +--
net/l2tp/Kconfig | 1 -
net/mpls/af_mpls.c | 3 +-
net/netfilter/Kconfig | 8 --
net/netfilter/core.c | 3 -
net/netfilter/nf_nat_masquerade.c | 21 +---
net/netfilter/nfnetlink_queue.c | 22 +++-
net/netfilter/utils.c | 1 -
net/openvswitch/actions.c | 3 +-
net/rxrpc/Kconfig | 2 +-
net/sched/sch_frag.c | 4 +-
net/sctp/Kconfig | 1 -
net/tipc/Kconfig | 1 -
net/tipc/udp_media.c | 9 +-
net/xfrm/espintcp.c | 5 +-
net/xfrm/xfrm_nat_keepalive.c | 4 +-
net/xfrm/xfrm_output.c | 3 +-
103 files changed, 310 insertions(+), 795 deletions(-)
delete mode 100644 include/net/ipv6_stubs.h
--
2.53.0