4.14-stable review patch. If anyone has any objections, please let me know.
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From: Roopa Prabhu roopa@cumulusnetworks.com
[ Upstream commit e99465b952861533d9ba748fdbecc96d9a36da3e ]
Problem: In vxlan_newlink, a default fdb entry is added before register_netdev. The default fdb creation function also notifies user-space of the fdb entry on the vxlan device which user-space does not know about yet. (RTM_NEWNEIGH goes before RTM_NEWLINK for the same ifindex).
This patch fixes the user-space netlink notification ordering issue with the following changes: - decouple fdb notify from fdb create. - Move fdb notify after register_netdev. - Call rtnl_configure_link in vxlan newlink handler to notify userspace about the newlink before fdb notify and hence avoiding the user-space race.
Fixes: afbd8bae9c79 ("vxlan: add implicit fdb entry for default destination") Signed-off-by: Roopa Prabhu roopa@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/vxlan.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)
--- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -3192,6 +3192,7 @@ static int __vxlan_dev_create(struct net { struct vxlan_net *vn = net_generic(net, vxlan_net_id); struct vxlan_dev *vxlan = netdev_priv(dev); + struct vxlan_fdb *f = NULL; int err;
err = vxlan_dev_configure(net, dev, conf, false, extack); @@ -3202,27 +3203,38 @@ static int __vxlan_dev_create(struct net
/* create an fdb entry for a valid default destination */ if (!vxlan_addr_any(&vxlan->default_dst.remote_ip)) { - err = vxlan_fdb_update(vxlan, all_zeros_mac, + err = vxlan_fdb_create(vxlan, all_zeros_mac, &vxlan->default_dst.remote_ip, NUD_REACHABLE | NUD_PERMANENT, - NLM_F_EXCL | NLM_F_CREATE, vxlan->cfg.dst_port, vxlan->default_dst.remote_vni, vxlan->default_dst.remote_vni, vxlan->default_dst.remote_ifindex, - NTF_SELF); + NTF_SELF, &f); if (err) return err; }
err = register_netdevice(dev); + if (err) + goto errout; + + err = rtnl_configure_link(dev, NULL); if (err) { - vxlan_fdb_delete_default(vxlan, vxlan->default_dst.remote_vni); - return err; + unregister_netdevice(dev); + goto errout; }
+ /* notify default fdb entry */ + if (f) + vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH); + list_add(&vxlan->next, &vn->vxlan_list); return 0; +errout: + if (f) + vxlan_fdb_destroy(vxlan, f, false); + return err; }
static int vxlan_nl2conf(struct nlattr *tb[], struct nlattr *data[], @@ -3451,6 +3463,7 @@ static int vxlan_changelink(struct net_d struct vxlan_rdst *dst = &vxlan->default_dst; struct vxlan_rdst old_dst; struct vxlan_config conf; + struct vxlan_fdb *f = NULL; int err;
err = vxlan_nl2conf(tb, data, @@ -3476,19 +3489,19 @@ static int vxlan_changelink(struct net_d old_dst.remote_ifindex, 0);
if (!vxlan_addr_any(&dst->remote_ip)) { - err = vxlan_fdb_update(vxlan, all_zeros_mac, + err = vxlan_fdb_create(vxlan, all_zeros_mac, &dst->remote_ip, NUD_REACHABLE | NUD_PERMANENT, - NLM_F_CREATE | NLM_F_APPEND, vxlan->cfg.dst_port, dst->remote_vni, dst->remote_vni, dst->remote_ifindex, - NTF_SELF); + NTF_SELF, &f); if (err) { spin_unlock_bh(&vxlan->hash_lock); return err; } + vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH); } spin_unlock_bh(&vxlan->hash_lock); }