3.16.62-rc1 review patch. If anyone has any objections, please let me know.
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From: Roopa Prabhu roopa@cumulusnetworks.com
commit 0241b836732f5f43c3f0fd9e9073c1fb24ea6757 upstream.
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 [bwh: Backported to 3.16: - Drop changes to vxlan_changelink() - Drop last argument to vxlan_fdb_destroy() - Adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2614,6 +2614,7 @@ static int vxlan_newlink(struct net *net struct vxlan_net *vn = net_generic(net, vxlan_net_id); struct vxlan_dev *vxlan = netdev_priv(dev), *tmp; struct vxlan_rdst *dst = &vxlan->default_dst; + struct vxlan_fdb *f = NULL; __u32 vni; int err; bool use_ipv6 = false; @@ -2751,27 +2752,38 @@ static int vxlan_newlink(struct net *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->dst_port, 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); - 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); + return err; }
static void vxlan_dellink(struct net_device *dev, struct list_head *head)