Re: [PATCH net v4 2/2] vxlan: reject VNI add when the default fdb entry is nexthop-backed

[henry martin]

Build failure confirmed: vxlan->cfg became an RCU-managed pointer in
current net/main, so .cfg.remote_ip no longer compiles.

v5 uses the function-local cfg pointer (&cfg->remote_ip) instead.
[1/2] unchanged, both dry-run applied on net/main, checkpatch clean.

Regards,
Henry

kernel test robot <lkp@xxxxxxxxx> 于2026年10月28日周三 17:38写道：
>
> Hi Henry,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on net/main]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Henry-Martin/vxlan-reject-VNI-add-when-the-default-fdb-entry-is-nexthop-backed/20261027-184713
> base:   net/main
> patch link:    https://lore.kernel.org/r/20261027104713.328028-2-bsdhenrymartin%40gmail.com
> patch subject: [PATCH net v4 2/2] vxlan: reject VNI add when the default fdb entry is nexthop-backed
> config: riscv-defconfig (https://download.01.org/0day-ci/archive/20261028/202610281752.nKGCORKp-lkp@xxxxxxxxx/config)
> compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 1da436a23e613c425fc9b868fc8deb979ede47a4)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261028/202610281752.nKGCORKp-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202610281752.nKGCORKp-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
> >> drivers/net/vxlan/vxlan_vnifilter.c:846:33: error: member reference type 'struct vxlan_config *' is a pointer; did you mean to use '->'?
>      846 |             !vxlan_addr_any(&vxlan->cfg.remote_ip)) {
>          |                              ~~~~~~~~~~^
>          |                                        ->
>    1 error generated.
>
>
> vim +846 drivers/net/vxlan/vxlan_vnifilter.c
>
>    819
>    820  static int vxlan_vni_add(struct vxlan_dev *vxlan,
>    821                           struct vxlan_vni_group *vg,
>    822                           u32 vni, union vxlan_addr *group,
>    823                           struct netlink_ext_ack *extack)
>    824  {
>    825          const struct vxlan_config *cfg = rtnl_dereference(vxlan->cfg);
>    826          struct vxlan_vni_node *vninode;
>    827          __be32 v = cpu_to_be32(vni);
>    828          bool changed = false;
>    829          int err = 0;
>    830
>    831          if (vxlan_vnifilter_lookup(vxlan, v))
>    832                  return vxlan_vni_update(vxlan, vg, v, group, &changed, extack);
>    833
>    834          err = vxlan_vni_in_use(vxlan->net, vxlan, cfg, v);
>    835          if (err) {
>    836                  NL_SET_ERR_MSG(extack, "VNI in use");
>    837                  return err;
>    838          }
>    839
>    840          /* A default fdb entry that is backed by a nexthop group can
>    841           * never take a remote; reject before the VNI is installed,
>    842           * otherwise a failure in vxlan_vni_update_group() would leave
>    843           * the VNI half-installed.
>    844           */
>    845          if ((group && !vxlan_addr_any(group)) ||
>  > 846              !vxlan_addr_any(&vxlan->cfg.remote_ip)) {
>    847                  if (vxlan_fdb_entry_nh_backed(vxlan, all_zeros_mac, v)) {
>    848                          NL_SET_ERR_MSG(extack,
>    849                                         "Cannot add a remote to a nexthop fdb entry");
>    850                          return -EOPNOTSUPP;
>    851                  }
>    852          }
>    853
>    854          vninode = vxlan_vni_alloc(vxlan, v);
>    855          if (!vninode)
>    856                  return -ENOMEM;
>    857
>    858          err = rhashtable_lookup_insert_fast(&vg->vni_hash,
>    859                                              &vninode->vnode,
>    860                                              vxlan_vni_rht_params);
>    861          if (err) {
>    862                  vxlan_vni_free(vninode);
>    863                  return err;
>    864          }
>    865
>    866          __vxlan_vni_add_list(vxlan, vg, vninode);
>    867
>    868          if (vxlan->dev->flags & IFF_UP)
>    869                  vxlan_vs_add_del_vninode(vxlan, vninode, false);
>    870
>    871          err = vxlan_vni_update_group(vxlan, vninode, group, true, &changed,
>    872                                       extack);
>    873
>    874          vxlan_vnifilter_notify(vxlan, vninode, RTM_NEWTUNNEL);
>    875
>    876          return err;
>    877  }
>    878
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki