diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 618ed88..e4141d6 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -824,6 +824,33 @@ static int ipvlan_addr6_event(struct notifier_block *unused,
 	return NOTIFY_OK;
 }
 
+static int ipvlan_addr6_validator_event(struct notifier_block *unused,
+					unsigned long event, void *ptr)
+{
+	struct in6_validator_info *i6vi = (struct in6_validator_info *)ptr;
+	struct net_device *dev = (struct net_device *)i6vi->i6vi_dev->dev;
+	struct ipvl_dev *ipvlan = netdev_priv(dev);
+
+	/* FIXME IPv6 autoconf calls us from bh without RTNL */
+	if (in_softirq())
+		return NOTIFY_DONE;
+
+	if (!netif_is_ipvlan(dev))
+		return NOTIFY_DONE;
+
+	if (!ipvlan || !ipvlan->port)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UP:
+		if (ipvlan_addr_busy(ipvlan->port, &i6vi->i6vi_addr, true))
+			return notifier_from_errno(-EADDRINUSE);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
 static int ipvlan_add_addr4(struct ipvl_dev *ipvlan, struct in_addr *ip4_addr)
 {
 	if (ipvlan_addr_busy(ipvlan->port, ip4_addr, false)) {
@@ -871,10 +898,37 @@ static int ipvlan_addr4_event(struct notifier_block *unused,
 	return NOTIFY_OK;
 }
 
+static int ipvlan_addr4_validator_event(struct notifier_block *unused,
+					unsigned long event, void *ptr)
+{
+	struct in_validator_info *ivi = (struct in_validator_info *)ptr;
+	struct net_device *dev = (struct net_device *)ivi->ivi_dev->dev;
+	struct ipvl_dev *ipvlan = netdev_priv(dev);
+
+	if (!netif_is_ipvlan(dev))
+		return NOTIFY_DONE;
+
+	if (!ipvlan || !ipvlan->port)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UP:
+		if (ipvlan_addr_busy(ipvlan->port, &ivi->ivi_addr, false))
+			return notifier_from_errno(-EADDRINUSE);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
 static struct notifier_block ipvlan_addr4_notifier_block __read_mostly = {
 	.notifier_call = ipvlan_addr4_event,
 };
 
+static struct notifier_block ipvlan_addr4_vtor_notifier_block __read_mostly = {
+	.notifier_call = ipvlan_addr4_validator_event,
+};
+
 static struct notifier_block ipvlan_notifier_block __read_mostly = {
 	.notifier_call = ipvlan_device_event,
 };
@@ -883,6 +937,10 @@ static struct notifier_block ipvlan_addr6_notifier_block __read_mostly = {
 	.notifier_call = ipvlan_addr6_event,
 };
 
+static struct notifier_block ipvlan_addr6_vtor_notifier_block __read_mostly = {
+	.notifier_call = ipvlan_addr6_validator_event,
+};
+
 static void ipvlan_ns_exit(struct net *net)
 {
 	struct ipvlan_netns *vnet = net_generic(net, ipvlan_netid);
@@ -907,7 +965,10 @@ static int __init ipvlan_init_module(void)
 	ipvlan_init_secret();
 	register_netdevice_notifier(&ipvlan_notifier_block);
 	register_inet6addr_notifier(&ipvlan_addr6_notifier_block);
+	register_inet6addr_validator_notifier(
+	    &ipvlan_addr6_vtor_notifier_block);
 	register_inetaddr_notifier(&ipvlan_addr4_notifier_block);
+	register_inetaddr_validator_notifier(&ipvlan_addr4_vtor_notifier_block);
 
 	err = register_pernet_subsys(&ipvlan_net_ops);
 	if (err < 0)
@@ -922,7 +983,11 @@ static int __init ipvlan_init_module(void)
 	return 0;
 error:
 	unregister_inetaddr_notifier(&ipvlan_addr4_notifier_block);
+	unregister_inetaddr_validator_notifier(
+	    &ipvlan_addr4_vtor_notifier_block);
 	unregister_inet6addr_notifier(&ipvlan_addr6_notifier_block);
+	unregister_inet6addr_validator_notifier(
+	    &ipvlan_addr6_vtor_notifier_block);
 	unregister_netdevice_notifier(&ipvlan_notifier_block);
 	return err;
 }
@@ -933,7 +998,11 @@ static void __exit ipvlan_cleanup_module(void)
 	unregister_pernet_subsys(&ipvlan_net_ops);
 	unregister_netdevice_notifier(&ipvlan_notifier_block);
 	unregister_inetaddr_notifier(&ipvlan_addr4_notifier_block);
+	unregister_inetaddr_validator_notifier(
+	    &ipvlan_addr4_vtor_notifier_block);
 	unregister_inet6addr_notifier(&ipvlan_addr6_notifier_block);
+	unregister_inet6addr_validator_notifier(
+	    &ipvlan_addr6_vtor_notifier_block);
 }
 
 module_init(ipvlan_init_module);
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index a2e9d6e..e7c04c4 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -150,8 +150,15 @@ struct in_ifaddr {
 	unsigned long		ifa_tstamp; /* updated timestamp */
 };
 
+struct in_validator_info {
+	__be32			ivi_addr;
+	struct in_device	*ivi_dev;
+};
+
 int register_inetaddr_notifier(struct notifier_block *nb);
 int unregister_inetaddr_notifier(struct notifier_block *nb);
+int register_inetaddr_validator_notifier(struct notifier_block *nb);
+int unregister_inetaddr_validator_notifier(struct notifier_block *nb);
 
 void inet_netconf_notify_devconf(struct net *net, int event, int type,
 				 int ifindex, struct ipv4_devconf *devconf);
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index b43a4ee..d0889cb 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -48,11 +48,15 @@ struct prefix_info {
 	struct in6_addr		prefix;
 };
 
-
 #include <linux/netdevice.h>
 #include <net/if_inet6.h>
 #include <net/ipv6.h>
 
+struct in6_validator_info {
+	struct in6_addr		i6vi_addr;
+	struct inet6_dev	*i6vi_dev;
+};
+
 #define IN6_ADDR_HSIZE_SHIFT	4
 #define IN6_ADDR_HSIZE		(1 << IN6_ADDR_HSIZE_SHIFT)
 
@@ -278,6 +282,10 @@ int register_inet6addr_notifier(struct notifier_block *nb);
 int unregister_inet6addr_notifier(struct notifier_block *nb);
 int inet6addr_notifier_call_chain(unsigned long val, void *v);
 
+int register_inet6addr_validator_notifier(struct notifier_block *nb);
+int unregister_inet6addr_validator_notifier(struct notifier_block *nb);
+int inet6addr_validator_notifier_call_chain(unsigned long val, void *v);
+
 void inet6_netconf_notify_devconf(struct net *net, int event, int type,
 				  int ifindex, struct ipv6_devconf *devconf);
 
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index df14815..a7dd088 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -176,6 +176,7 @@ EXPORT_SYMBOL(__ip_dev_find);
 static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);
 
 static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
+static BLOCKING_NOTIFIER_HEAD(inetaddr_validator_chain);
 static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
 			 int destroy);
 #ifdef CONFIG_SYSCTL
@@ -441,6 +442,8 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 {
 	struct in_device *in_dev = ifa->ifa_dev;
 	struct in_ifaddr *ifa1, **ifap, **last_primary;
+	struct in_validator_info ivi;
+	int ret;
 
 	ASSERT_RTNL();
 
@@ -471,6 +474,23 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 		}
 	}
 
+	/* Allow any devices that wish to register ifaddr validtors to weigh
+	 * in now, before changes are committed.  The rntl lock is serializing
+	 * access here, so the state should not change between a validator call
+	 * and a final notify on commit.  This isn't invoked on promotion under
+	 * the assumption that validators are checking the address itself, and
+	 * not the flags.
+	 */
+	ivi.ivi_addr = ifa->ifa_address;
+	ivi.ivi_dev = ifa->ifa_dev;
+	ret = blocking_notifier_call_chain(&inetaddr_validator_chain,
+					   NETDEV_UP, &ivi);
+	ret = notifier_to_errno(ret);
+	if (ret) {
+		inet_free_ifa(ifa);
+		return ret;
+	}
+
 	if (!(ifa->ifa_flags & IFA_F_SECONDARY)) {
 		prandom_seed((__force u32) ifa->ifa_local);
 		ifap = last_primary;
@@ -1356,6 +1376,19 @@ int unregister_inetaddr_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_inetaddr_notifier);
 
+int register_inetaddr_validator_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&inetaddr_validator_chain, nb);
+}
+EXPORT_SYMBOL(register_inetaddr_validator_notifier);
+
+int unregister_inetaddr_validator_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&inetaddr_validator_chain,
+	    nb);
+}
+EXPORT_SYMBOL(unregister_inetaddr_validator_notifier);
+
 /* Rename ifa_labels for a device name change. Make some effort to preserve
  * existing alias numbering and to create unique labels if possible.
 */
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 25443fd..0aa36b0 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -963,6 +963,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 	struct net *net = dev_net(idev->dev);
 	struct inet6_ifaddr *ifa = NULL;
 	struct rt6_info *rt;
+	struct in6_validator_info i6vi;
 	unsigned int hash;
 	int err = 0;
 	int addr_type = ipv6_addr_type(addr);
@@ -974,6 +975,9 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 		return ERR_PTR(-EADDRNOTAVAIL);
 
 	rcu_read_lock_bh();
+
+	in6_dev_hold(idev);
+
 	if (idev->dead) {
 		err = -ENODEV;			/*XXX*/
 		goto out2;
@@ -984,6 +988,17 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 		goto out2;
 	}
 
+	i6vi.i6vi_addr = *addr;
+	i6vi.i6vi_dev = idev;
+	rcu_read_unlock_bh();
+
+	err = inet6addr_validator_notifier_call_chain(NETDEV_UP, &i6vi);
+
+	rcu_read_lock_bh();
+	err = notifier_to_errno(err);
+	if (err)
+		goto out2;
+
 	spin_lock(&addrconf_hash_lock);
 
 	/* Ignore adding duplicate addresses on an interface */
@@ -1034,7 +1049,6 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 	ifa->rt = rt;
 
 	ifa->idev = idev;
-	in6_dev_hold(idev);
 	/* For caller */
 	in6_ifa_hold(ifa);
 
@@ -1062,6 +1076,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 		inet6addr_notifier_call_chain(NETDEV_UP, ifa);
 	else {
 		kfree(ifa);
+		in6_dev_put(idev);
 		ifa = ERR_PTR(err);
 	}
 
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index bfa941f..9e3488d 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -88,6 +88,7 @@ int __ipv6_addr_type(const struct in6_addr *addr)
 EXPORT_SYMBOL(__ipv6_addr_type);
 
 static ATOMIC_NOTIFIER_HEAD(inet6addr_chain);
+static ATOMIC_NOTIFIER_HEAD(inet6addr_validator_chain);
 
 int register_inet6addr_notifier(struct notifier_block *nb)
 {
@@ -107,6 +108,24 @@ int inet6addr_notifier_call_chain(unsigned long val, void *v)
 }
 EXPORT_SYMBOL(inet6addr_notifier_call_chain);
 
+int register_inet6addr_validator_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&inet6addr_validator_chain, nb);
+}
+EXPORT_SYMBOL(register_inet6addr_validator_notifier);
+
+int unregister_inet6addr_validator_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&inet6addr_validator_chain, nb);
+}
+EXPORT_SYMBOL(unregister_inet6addr_validator_notifier);
+
+int inet6addr_validator_notifier_call_chain(unsigned long val, void *v)
+{
+	return atomic_notifier_call_chain(&inet6addr_validator_chain, val, v);
+}
+EXPORT_SYMBOL(inet6addr_validator_notifier_call_chain);
+
 static int eafnosupport_ipv6_dst_lookup(struct net *net, struct sock *u1,
 					struct dst_entry **u2,
 					struct flowi6 *u3)