[patch 55/55] [PATCH] net: fix NULL dereferences in check_peer_redir()

[Greg KH <gregkh@linuxfoundation.org>]

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <eric.dumazet@gmail.com>

[ Upstream commit d3aaeb38c40e5a6c08dd31a1b64da65c4352be36, along
  with dependent backports of commits:
     69cce1d1404968f78b177a0314f5822d5afdbbfb
     9de79c127cccecb11ae6a21ab1499e87aa222880
     218fa90f072e4aeff9003d57e390857f4f35513e
     580da35a31f91a594f3090b7a2c39b85cb051a12
     f7e57044eeb1841847c24aa06766c8290c202583
     e049f28883126c689cf95859480d9ee4ab23b7fa ]

Gergely Kalman reported crashes in check_peer_redir().

It appears commit f39925dbde778 (ipv4: Cache learned redirect
information in inetpeer.) added a race, leading to possible NULL ptr
dereference.

Since we can now change dst neighbour, we should make sure a reader can
safely use a neighbour.

Add RCU protection to dst neighbour, and make sure check_peer_redir()
can be called safely by different cpus in parallel.

As neighbours are already freed after one RCU grace period, this patch
should not add typical RCU penalty (cache cold effects)

Many thanks to Gergely for providing a pretty report pointing to the
bug.

Reported-by: Gergely Kalman <synapse@hippy.csoma.elte.hu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/infiniband/core/addr.c                 |   16 ++++--
 drivers/infiniband/hw/cxgb3/iwch_cm.c          |   16 +++++-
 drivers/infiniband/hw/cxgb4/cm.c               |   46 ++++++++++---------
 drivers/infiniband/hw/mlx4/qp.c                |    2 
 drivers/infiniband/hw/nes/nes_cm.c             |    8 ++-
 drivers/infiniband/ulp/ipoib/ipoib_main.c      |   59 ++++++++++++++++---------
 drivers/infiniband/ulp/ipoib/ipoib_multicast.c |   24 ++++++----
 drivers/net/cxgb3/cxgb3_offload.c              |    8 +--
 drivers/s390/net/qeth_l3_main.c                |   23 +++++++--
 drivers/scsi/cxgbi/cxgb3i/cxgb3i.c             |    2 
 drivers/scsi/cxgbi/cxgb4i/cxgb4i.c             |    2 
 drivers/scsi/cxgbi/libcxgbi.c                  |    4 -
 include/net/arp.h                              |    1 
 include/net/dst.h                              |   27 ++++++++++-
 net/atm/clip.c                                 |   16 ++++--
 net/bridge/br_netfilter.c                      |    6 +-
 net/core/dst.c                                 |   15 ++++--
 net/core/neighbour.c                           |   19 +++++---
 net/decnet/dn_neigh.c                          |    8 +--
 net/decnet/dn_route.c                          |   18 ++++---
 net/ipv4/arp.c                                 |   28 +++++++----
 net/ipv4/ip_gre.c                              |    2 
 net/ipv4/ip_output.c                           |   22 +++++++--
 net/ipv4/route.c                               |   31 ++++++++-----
 net/ipv6/addrconf.c                            |    2 
 net/ipv6/ip6_fib.c                             |    2 
 net/ipv6/ip6_output.c                          |   40 +++++++++++++---
 net/ipv6/ndisc.c                               |    4 -
 net/ipv6/route.c                               |   59 +++++++++++++++----------
 net/ipv6/sit.c                                 |    4 -
 net/sched/sch_teql.c                           |   31 ++++++++-----
 net/xfrm/xfrm_policy.c                         |    2 
 32 files changed, 358 insertions(+), 189 deletions(-)

--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -215,7 +215,9 @@ static int addr4_resolve(struct sockaddr
 
 	neigh = neigh_lookup(&arp_tbl, &rt->rt_gateway, rt->dst.dev);
 	if (!neigh || !(neigh->nud_state & NUD_VALID)) {
-		neigh_event_send(rt->dst.neighbour, NULL);
+		rcu_read_lock();
+		neigh_event_send(dst_get_neighbour(&rt->dst), NULL);
+		rcu_read_unlock();
 		ret = -ENODATA;
 		if (neigh)
 			goto release;
@@ -273,14 +275,16 @@ static int addr6_resolve(struct sockaddr
 		goto put;
 	}
 
-	neigh = dst->neighbour;
+	rcu_read_lock();
+	neigh = dst_get_neighbour(dst);
 	if (!neigh || !(neigh->nud_state & NUD_VALID)) {
-		neigh_event_send(dst->neighbour, NULL);
+		if (neigh)
+			neigh_event_send(neigh, NULL);
 		ret = -ENODATA;
-		goto put;
+	} else {
+		ret = rdma_copy_addr(addr, dst->dev, neigh->ha);
 	}
-
-	ret = rdma_copy_addr(addr, dst->dev, neigh->ha);
+	rcu_read_unlock();
 put:
 	dst_release(dst);
 	return ret;
--- a/drivers/infiniband/hw/cxgb3/iwch_cm.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_cm.c
@@ -1328,6 +1328,7 @@ static int pass_accept_req(struct t3cdev
 	struct iwch_ep *child_ep, *parent_ep = ctx;
 	struct cpl_pass_accept_req *req = cplhdr(skb);
 	unsigned int hwtid = GET_TID(req);
+	struct neighbour *neigh;
 	struct dst_entry *dst;
 	struct l2t_entry *l2t;
 	struct rtable *rt;
@@ -1364,7 +1365,10 @@ static int pass_accept_req(struct t3cdev
 		goto reject;
 	}
 	dst = &rt->dst;
-	l2t = t3_l2t_get(tdev, dst->neighbour, dst->neighbour->dev);
+	rcu_read_lock();
+	neigh = dst_get_neighbour(dst);
+	l2t = t3_l2t_get(tdev, neigh, neigh->dev);
+	rcu_read_unlock();
 	if (!l2t) {
 		printk(KERN_ERR MOD "%s - failed to allocate l2t entry!\n",
 		       __func__);
@@ -1874,10 +1878,11 @@ static int is_loopback_dst(struct iw_cm_
 
 int iwch_connect(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
 {
-	int err = 0;
 	struct iwch_dev *h = to_iwch_dev(cm_id->device);
+	struct neighbour *neigh;
 	struct iwch_ep *ep;
 	struct rtable *rt;
+	int err = 0;
 
 	if (is_loopback_dst(cm_id)) {
 		err = -ENOSYS;
@@ -1933,9 +1938,12 @@ int iwch_connect(struct iw_cm_id *cm_id,
 	}
 	ep->dst = &rt->dst;
 
+	rcu_read_lock();
+	neigh = dst_get_neighbour(ep->dst);
+
 	/* get a l2t entry */
-	ep->l2t = t3_l2t_get(ep->com.tdev, ep->dst->neighbour,
-			     ep->dst->neighbour->dev);
+	ep->l2t = t3_l2t_get(ep->com.tdev, neigh, neigh->dev);
+	rcu_read_unlock();
 	if (!ep->l2t) {
 		printk(KERN_ERR MOD "%s - cannot alloc l2e.\n", __func__);
 		err = -ENOMEM;
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -1325,6 +1325,7 @@ static int pass_accept_req(struct c4iw_d
 	unsigned int stid = GET_POPEN_TID(ntohl(req->tos_stid));
 	struct tid_info *t = dev->rdev.lldi.tids;
 	unsigned int hwtid = GET_TID(req);
+	struct neighbour *neigh;
 	struct dst_entry *dst;
 	struct l2t_entry *l2t;
 	struct rtable *rt;
@@ -1357,11 +1358,12 @@ static int pass_accept_req(struct c4iw_d
 		goto reject;
 	}
 	dst = &rt->dst;
-	if (dst->neighbour->dev->flags & IFF_LOOPBACK) {
+	rcu_read_lock();
+	neigh = dst_get_neighbour(dst);
+	if (neigh->dev->flags & IFF_LOOPBACK) {
 		pdev = ip_dev_find(&init_net, peer_ip);
 		BUG_ON(!pdev);
-		l2t = cxgb4_l2t_get(dev->rdev.lldi.l2t, dst->neighbour,
-				    pdev, 0);
+		l2t = cxgb4_l2t_get(dev->rdev.lldi.l2t, neigh, pdev, 0);
 		mtu = pdev->mtu;
 		tx_chan = cxgb4_port_chan(pdev);
 		smac_idx = (cxgb4_port_viid(pdev) & 0x7F) << 1;
@@ -1372,18 +1374,18 @@ static int pass_accept_req(struct c4iw_d
 		rss_qid = dev->rdev.lldi.rxq_ids[cxgb4_port_idx(pdev) * step];
 		dev_put(pdev);
 	} else {
-		l2t = cxgb4_l2t_get(dev->rdev.lldi.l2t, dst->neighbour,
-					dst->neighbour->dev, 0);
+		l2t = cxgb4_l2t_get(dev->rdev.lldi.l2t, neigh, neigh->dev, 0);
 		mtu = dst_mtu(dst);
-		tx_chan = cxgb4_port_chan(dst->neighbour->dev);
-		smac_idx = (cxgb4_port_viid(dst->neighbour->dev) & 0x7F) << 1;
+		tx_chan = cxgb4_port_chan(neigh->dev);
+		smac_idx = (cxgb4_port_viid(neigh->dev) & 0x7F) << 1;
 		step = dev->rdev.lldi.ntxq / dev->rdev.lldi.nchan;
-		txq_idx = cxgb4_port_idx(dst->neighbour->dev) * step;
-		ctrlq_idx = cxgb4_port_idx(dst->neighbour->dev);
+		txq_idx = cxgb4_port_idx(neigh->dev) * step;
+		ctrlq_idx = cxgb4_port_idx(neigh->dev);
 		step = dev->rdev.lldi.nrxq / dev->rdev.lldi.nchan;
 		rss_qid = dev->rdev.lldi.rxq_ids[
-			  cxgb4_port_idx(dst->neighbour->dev) * step];
+			  cxgb4_port_idx(neigh->dev) * step];
 	}
+	rcu_read_unlock();
 	if (!l2t) {
 		printk(KERN_ERR MOD "%s - failed to allocate l2t entry!\n",
 		       __func__);
@@ -1847,6 +1849,7 @@ int c4iw_connect(struct iw_cm_id *cm_id,
 	struct c4iw_ep *ep;
 	struct rtable *rt;
 	struct net_device *pdev;
+	struct neighbour *neigh;
 	int step;
 
 	if ((conn_param->ord > c4iw_max_read_depth) ||
@@ -1908,14 +1911,16 @@ int c4iw_connect(struct iw_cm_id *cm_id,
 	}
 	ep->dst = &rt->dst;
 
+	rcu_read_lock();
+	neigh = dst_get_neighbour(ep->dst);
+
 	/* get a l2t entry */
-	if (ep->dst->neighbour->dev->flags & IFF_LOOPBACK) {
+	if (neigh->dev->flags & IFF_LOOPBACK) {
 		PDBG("%s LOOPBACK\n", __func__);
 		pdev = ip_dev_find(&init_net,
 				   cm_id->remote_addr.sin_addr.s_addr);
 		ep->l2t = cxgb4_l2t_get(ep->com.dev->rdev.lldi.l2t,
-					ep->dst->neighbour,
-					pdev, 0);
+					neigh, pdev, 0);
 		ep->mtu = pdev->mtu;
 		ep->tx_chan = cxgb4_port_chan(pdev);
 		ep->smac_idx = (cxgb4_port_viid(pdev) & 0x7F) << 1;
@@ -1930,21 +1935,20 @@ int c4iw_connect(struct iw_cm_id *cm_id,
 		dev_put(pdev);
 	} else {
 		ep->l2t = cxgb4_l2t_get(ep->com.dev->rdev.lldi.l2t,
-					ep->dst->neighbour,
-					ep->dst->neighbour->dev, 0);
+					neigh, neigh->dev, 0);
 		ep->mtu = dst_mtu(ep->dst);
-		ep->tx_chan = cxgb4_port_chan(ep->dst->neighbour->dev);
-		ep->smac_idx = (cxgb4_port_viid(ep->dst->neighbour->dev) &
-				0x7F) << 1;
+		ep->tx_chan = cxgb4_port_chan(neigh->dev);
+		ep->smac_idx = (cxgb4_port_viid(neigh->dev) & 0x7F) << 1;
 		step = ep->com.dev->rdev.lldi.ntxq /
 		       ep->com.dev->rdev.lldi.nchan;
-		ep->txq_idx = cxgb4_port_idx(ep->dst->neighbour->dev) * step;
-		ep->ctrlq_idx = cxgb4_port_idx(ep->dst->neighbour->dev);
+		ep->txq_idx = cxgb4_port_idx(neigh->dev) * step;
+		ep->ctrlq_idx = cxgb4_port_idx(neigh->dev);
 		step = ep->com.dev->rdev.lldi.nrxq /
 		       ep->com.dev->rdev.lldi.nchan;
 		ep->rss_qid = ep->com.dev->rdev.lldi.rxq_ids[
-			      cxgb4_port_idx(ep->dst->neighbour->dev) * step];
+			      cxgb4_port_idx(neigh->dev) * step];
 	}
+	rcu_read_unlock();
 	if (!ep->l2t) {
 		printk(KERN_ERR MOD "%s - cannot alloc l2e.\n", __func__);
 		err = -ENOMEM;
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -1301,7 +1301,7 @@ static int build_mlx_header(struct mlx4_
 	int is_eth;
 	int is_vlan = 0;
 	int is_grh;
-	u16 vlan;
+	u16 vlan = 0;
 
 	send_size = 0;
 	for (i = 0; i < wr->num_sge; ++i)
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -1150,9 +1150,11 @@ static int nes_addr_resolve_neigh(struct
 		neigh_release(neigh);
 	}
 
-	if ((neigh == NULL) || (!(neigh->nud_state & NUD_VALID)))
-		neigh_event_send(rt->dst.neighbour, NULL);
-
+	if ((neigh == NULL) || (!(neigh->nud_state & NUD_VALID))) {
+		rcu_read_lock();
+		neigh_event_send(dst_get_neighbour(&rt->dst), NULL);
+		rcu_read_unlock();
+	}
 	ip_rt_put(rt);
 	return rc;
 }
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -555,14 +555,17 @@ static int path_rec_start(struct net_dev
 	return 0;
 }
 
+/* called with rcu_read_lock */
 static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	struct ipoib_path *path;
 	struct ipoib_neigh *neigh;
+	struct neighbour *n;
 	unsigned long flags;
 
-	neigh = ipoib_neigh_alloc(skb_dst(skb)->neighbour, skb->dev);
+	n = dst_get_neighbour(skb_dst(skb));
+	neigh = ipoib_neigh_alloc(n, skb->dev);
 	if (!neigh) {
 		++dev->stats.tx_dropped;
 		dev_kfree_skb_any(skb);
@@ -571,9 +574,9 @@ static void neigh_add_path(struct sk_buf
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	path = __path_find(dev, skb_dst(skb)->neighbour->ha + 4);
+	path = __path_find(dev, n->ha + 4);
 	if (!path) {
-		path = path_rec_create(dev, skb_dst(skb)->neighbour->ha + 4);
+		path = path_rec_create(dev, n->ha + 4);
 		if (!path)
 			goto err_path;
 
@@ -607,7 +610,7 @@ static void neigh_add_path(struct sk_buf
 			}
 		} else {
 			spin_unlock_irqrestore(&priv->lock, flags);
-			ipoib_send(dev, skb, path->ah, IPOIB_QPN(skb_dst(skb)->neighbour->ha));
+			ipoib_send(dev, skb, path->ah, IPOIB_QPN(n->ha));
 			return;
 		}
 	} else {
@@ -634,20 +637,24 @@ err_drop:
 	spin_unlock_irqrestore(&priv->lock, flags);
 }
 
+/* called with rcu_read_lock */
 static void ipoib_path_lookup(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = netdev_priv(skb->dev);
+	struct dst_entry *dst = skb_dst(skb);
+	struct neighbour *n;
 
 	/* Look up path record for unicasts */
-	if (skb_dst(skb)->neighbour->ha[4] != 0xff) {
+	n = dst_get_neighbour(dst);
+	if (n->ha[4] != 0xff) {
 		neigh_add_path(skb, dev);
 		return;
 	}
 
 	/* Add in the P_Key for multicasts */
-	skb_dst(skb)->neighbour->ha[8] = (priv->pkey >> 8) & 0xff;
-	skb_dst(skb)->neighbour->ha[9] = priv->pkey & 0xff;
-	ipoib_mcast_send(dev, skb_dst(skb)->neighbour->ha + 4, skb);
+	n->ha[8] = (priv->pkey >> 8) & 0xff;
+	n->ha[9] = priv->pkey & 0xff;
+	ipoib_mcast_send(dev, n->ha + 4, skb);
 }
 
 static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
@@ -712,18 +719,23 @@ static int ipoib_start_xmit(struct sk_bu
 {
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	struct ipoib_neigh *neigh;
+	struct neighbour *n = NULL;
 	unsigned long flags;
 
-	if (likely(skb_dst(skb) && skb_dst(skb)->neighbour)) {
-		if (unlikely(!*to_ipoib_neigh(skb_dst(skb)->neighbour))) {
+	rcu_read_lock();
+	if (likely(skb_dst(skb)))
+		n = dst_get_neighbour(skb_dst(skb));
+
+	if (likely(n)) {
+		if (unlikely(!*to_ipoib_neigh(n))) {
 			ipoib_path_lookup(skb, dev);
-			return NETDEV_TX_OK;
+			goto unlock;
 		}
 
-		neigh = *to_ipoib_neigh(skb_dst(skb)->neighbour);
+		neigh = *to_ipoib_neigh(n);
 
 		if (unlikely((memcmp(&neigh->dgid.raw,
-				     skb_dst(skb)->neighbour->ha + 4,
+				     n->ha + 4,
 				     sizeof(union ib_gid))) ||
 			     (neigh->dev != dev))) {
 			spin_lock_irqsave(&priv->lock, flags);
@@ -740,17 +752,17 @@ static int ipoib_start_xmit(struct sk_bu
 			ipoib_neigh_free(dev, neigh);
 			spin_unlock_irqrestore(&priv->lock, flags);
 			ipoib_path_lookup(skb, dev);
-			return NETDEV_TX_OK;
+			goto unlock;
 		}
 
 		if (ipoib_cm_get(neigh)) {
 			if (ipoib_cm_up(neigh)) {
 				ipoib_cm_send(dev, skb, ipoib_cm_get(neigh));
-				return NETDEV_TX_OK;
+				goto unlock;
 			}
 		} else if (neigh->ah) {
-			ipoib_send(dev, skb, neigh->ah, IPOIB_QPN(skb_dst(skb)->neighbour->ha));
-			return NETDEV_TX_OK;
+			ipoib_send(dev, skb, neigh->ah, IPOIB_QPN(n->ha));
+			goto unlock;
 		}
 
 		if (skb_queue_len(&neigh->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
@@ -784,13 +796,14 @@ static int ipoib_start_xmit(struct sk_bu
 					   phdr->hwaddr + 4);
 				dev_kfree_skb_any(skb);
 				++dev->stats.tx_dropped;
-				return NETDEV_TX_OK;
+				goto unlock;
 			}
 
 			unicast_arp_send(skb, dev, phdr);
 		}
 	}
-
+unlock:
+	rcu_read_unlock();
 	return NETDEV_TX_OK;
 }
 
@@ -812,6 +825,8 @@ static int ipoib_hard_header(struct sk_b
 			     const void *daddr, const void *saddr, unsigned len)
 {
 	struct ipoib_header *header;
+	struct dst_entry *dst;
+	struct neighbour *n;
 
 	header = (struct ipoib_header *) skb_push(skb, sizeof *header);
 
@@ -823,7 +838,11 @@ static int ipoib_hard_header(struct sk_b
 	 * destination address onto the front of the skb so we can
 	 * figure out where to send the packet later.
 	 */
-	if ((!skb_dst(skb) || !skb_dst(skb)->neighbour) && daddr) {
+	dst = skb_dst(skb);
+	n = NULL;
+	if (dst)
+		n = dst_get_neighbour_raw(dst);
+	if ((!dst || !n) && daddr) {
 		struct ipoib_pseudoheader *phdr =
 			(struct ipoib_pseudoheader *) skb_push(skb, sizeof *phdr);
 		memcpy(phdr->hwaddr, daddr, INFINIBAND_ALEN);
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -258,11 +258,15 @@ static int ipoib_mcast_join_finish(struc
 	netif_tx_lock_bh(dev);
 	while (!skb_queue_empty(&mcast->pkt_queue)) {
 		struct sk_buff *skb = skb_dequeue(&mcast->pkt_queue);
+		struct dst_entry *dst = skb_dst(skb);
+		struct neighbour *n = NULL;
+
 		netif_tx_unlock_bh(dev);
 
 		skb->dev = dev;
-
-		if (!skb_dst(skb) || !skb_dst(skb)->neighbour) {
+		if (dst)
+			n = dst_get_neighbour_raw(dst);
+		if (!dst || !n) {
 			/* put pseudoheader back on for next time */
 			skb_push(skb, sizeof (struct ipoib_pseudoheader));
 		}
@@ -715,11 +719,15 @@ void ipoib_mcast_send(struct net_device
 
 out:
 	if (mcast && mcast->ah) {
-		if (skb_dst(skb)		&&
-		    skb_dst(skb)->neighbour &&
-		    !*to_ipoib_neigh(skb_dst(skb)->neighbour)) {
-			struct ipoib_neigh *neigh = ipoib_neigh_alloc(skb_dst(skb)->neighbour,
-									skb->dev);
+		struct dst_entry *dst = skb_dst(skb);
+		struct neighbour *n = NULL;
+
+		rcu_read_lock();
+		if (dst)
+			n = dst_get_neighbour(dst);
+		if (n && !*to_ipoib_neigh(n)) {
+			struct ipoib_neigh *neigh = ipoib_neigh_alloc(n,
+								      skb->dev);
 
 			if (neigh) {
 				kref_get(&mcast->ah->ref);
@@ -727,7 +735,7 @@ out:
 				list_add_tail(&neigh->list, &mcast->neigh_list);
 			}
 		}
-
+		rcu_read_unlock();
 		spin_unlock_irqrestore(&priv->lock, flags);
 		ipoib_send(dev, skb, mcast->ah, IB_MULTICAST_QPN);
 		return;
--- a/drivers/net/cxgb3/cxgb3_offload.c
+++ b/drivers/net/cxgb3/cxgb3_offload.c
@@ -971,7 +971,7 @@ static int nb_callback(struct notifier_b
 	case (NETEVENT_REDIRECT):{
 		struct netevent_redirect *nr = ctx;
 		cxgb_redirect(nr->old, nr->new);
-		cxgb_neigh_update(nr->new->neighbour);
+		cxgb_neigh_update(dst_get_neighbour(nr->new));
 		break;
 	}
 	default:
@@ -1116,8 +1116,8 @@ static void cxgb_redirect(struct dst_ent
 	struct l2t_entry *e;
 	struct t3c_tid_entry *te;
 
-	olddev = old->neighbour->dev;
-	newdev = new->neighbour->dev;
+	olddev = dst_get_neighbour(old)->dev;
+	newdev = dst_get_neighbour(new)->dev;
 	if (!is_offloading(olddev))
 		return;
 	if (!is_offloading(newdev)) {
@@ -1134,7 +1134,7 @@ static void cxgb_redirect(struct dst_ent
 	}
 
 	/* Add new L2T entry */
-	e = t3_l2t_get(tdev, new->neighbour, newdev);
+	e = t3_l2t_get(tdev, dst_get_neighbour(new), newdev);
 	if (!e) {
 		printk(KERN_ERR "%s: couldn't allocate new l2t entry!\n",
 		       __func__);
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2742,9 +2742,14 @@ static int qeth_l3_do_ioctl(struct net_d
 int inline qeth_l3_get_cast_type(struct qeth_card *card, struct sk_buff *skb)
 {
 	int cast_type = RTN_UNSPEC;
+	struct neighbour *n = NULL;
+	struct dst_entry *dst;
 
-	if (skb_dst(skb) && skb_dst(skb)->neighbour) {
-		cast_type = skb_dst(skb)->neighbour->type;
+	dst = skb_dst(skb);
+	if (dst)
+		n = dst_get_neighbour(dst);
+	if (n) {
+		cast_type = n->type;
 		if ((cast_type == RTN_BROADCAST) ||
 		    (cast_type == RTN_MULTICAST) ||
 		    (cast_type == RTN_ANYCAST))
@@ -2787,6 +2792,9 @@ int inline qeth_l3_get_cast_type(struct
 static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
 		struct sk_buff *skb, int ipv, int cast_type)
 {
+	struct neighbour *n = NULL;
+	struct dst_entry *dst;
+
 	memset(hdr, 0, sizeof(struct qeth_hdr));
 	hdr->hdr.l3.id = QETH_HEADER_TYPE_LAYER3;
 	hdr->hdr.l3.ext_flags = 0;
@@ -2804,13 +2812,16 @@ static void qeth_l3_fill_header(struct q
 	}
 
 	hdr->hdr.l3.length = skb->len - sizeof(struct qeth_hdr);
+	dst = skb_dst(skb);
+	if (dst)
+		n = dst_get_neighbour(dst);
 	if (ipv == 4) {
 		/* IPv4 */
 		hdr->hdr.l3.flags = qeth_l3_get_qeth_hdr_flags4(cast_type);
 		memset(hdr->hdr.l3.dest_addr, 0, 12);
-		if ((skb_dst(skb)) && (skb_dst(skb)->neighbour)) {
+		if (n) {
 			*((u32 *) (&hdr->hdr.l3.dest_addr[12])) =
-			    *((u32 *) skb_dst(skb)->neighbour->primary_key);
+			    *((u32 *) n->primary_key);
 		} else {
 			/* fill in destination address used in ip header */
 			*((u32 *) (&hdr->hdr.l3.dest_addr[12])) =
@@ -2821,9 +2832,9 @@ static void qeth_l3_fill_header(struct q
 		hdr->hdr.l3.flags = qeth_l3_get_qeth_hdr_flags6(cast_type);
 		if (card->info.type == QETH_CARD_TYPE_IQD)
 			hdr->hdr.l3.flags &= ~QETH_HDR_PASSTHRU;
-		if ((skb_dst(skb)) && (skb_dst(skb)->neighbour)) {
+		if (n) {
 			memcpy(hdr->hdr.l3.dest_addr,
-			       skb_dst(skb)->neighbour->primary_key, 16);
+			       n->primary_key, 16);
 		} else {
 			/* fill in destination address used in ip header */
 			memcpy(hdr->hdr.l3.dest_addr,
--- a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
+++ b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
@@ -985,7 +985,7 @@ static int init_act_open(struct cxgbi_so
 		csk->saddr.sin_addr.s_addr = chba->ipv4addr;
 
 	csk->rss_qid = 0;
-	csk->l2t = t3_l2t_get(t3dev, dst->neighbour, ndev);
+	csk->l2t = t3_l2t_get(t3dev, dst_get_neighbour(dst), ndev);
 	if (!csk->l2t) {
 		pr_err("NO l2t available.\n");
 		return -EINVAL;
--- a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
+++ b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
@@ -1160,7 +1160,7 @@ static int init_act_open(struct cxgbi_so
 	cxgbi_sock_set_flag(csk, CTPF_HAS_ATID);
 	cxgbi_sock_get(csk);
 
-	csk->l2t = cxgb4_l2t_get(lldi->l2t, csk->dst->neighbour, ndev, 0);
+	csk->l2t = cxgb4_l2t_get(lldi->l2t, dst_get_neighbour(csk->dst), ndev, 0);
 	if (!csk->l2t) {
 		pr_err("%s, cannot alloc l2t.\n", ndev->name);
 		goto rel_resource;
--- a/drivers/scsi/cxgbi/libcxgbi.c
+++ b/drivers/scsi/cxgbi/libcxgbi.c
@@ -492,7 +492,7 @@ static struct cxgbi_sock *cxgbi_check_ro
 		goto err_out;
 	}
 	dst = &rt->dst;
-	ndev = dst->neighbour->dev;
+	ndev = dst_get_neighbour(dst)->dev;
 
 	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
 		pr_info("multi-cast route %pI4, port %u, dev %s.\n",
@@ -506,7 +506,7 @@ static struct cxgbi_sock *cxgbi_check_ro
 		ndev = ip_dev_find(&init_net, daddr->sin_addr.s_addr);
 		mtu = ndev->mtu;
 		pr_info("rt dev %s, loopback -> %s, mtu %u.\n",
-			dst->neighbour->dev->name, ndev->name, mtu);
+			dst_get_neighbour(dst)->dev->name, ndev->name, mtu);
 	}
 
 	cdev = cxgbi_device_find_by_netdev(ndev, &port);
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -16,6 +16,7 @@ extern void     arp_send(int type, int p
 			 const unsigned char *dest_hw,
 			 const unsigned char *src_hw, const unsigned char *th);
 extern int	arp_bind_neighbour(struct dst_entry *dst);
+extern struct neighbour *__arp_bind_neighbour(struct dst_entry *dst, __be32 nexthop);
 extern int	arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);
 extern void	arp_ifdown(struct net_device *dev);
 
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -37,7 +37,7 @@ struct dst_entry {
 	unsigned long		_metrics;
 	unsigned long		expires;
 	struct dst_entry	*path;
-	struct neighbour	*neighbour;
+	struct neighbour __rcu	*_neighbour;
 	struct hh_cache		*hh;
 #ifdef CONFIG_XFRM
 	struct xfrm_state	*xfrm;
@@ -86,6 +86,21 @@ struct dst_entry {
 	};
 };
 
+static inline struct neighbour *dst_get_neighbour(struct dst_entry *dst)
+{
+	return rcu_dereference(dst->_neighbour);
+}
+
+static inline struct neighbour *dst_get_neighbour_raw(struct dst_entry *dst)
+{
+	return rcu_dereference_raw(dst->_neighbour);
+}
+
+static inline void dst_set_neighbour(struct dst_entry *dst, struct neighbour *neigh)
+{
+	rcu_assign_pointer(dst->_neighbour, neigh);
+}
+
 extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
 extern const u32 dst_default_metrics[RTAX_MAX];
 
@@ -371,8 +386,14 @@ static inline void dst_rcu_free(struct r
 
 static inline void dst_confirm(struct dst_entry *dst)
 {
-	if (dst)
-		neigh_confirm(dst->neighbour);
+	if (dst) {
+		struct neighbour *n;
+
+		rcu_read_lock();
+		n = dst_get_neighbour(dst);
+		neigh_confirm(n);
+		rcu_read_unlock();
+	}
 }
 
 static inline void dst_link_failure(struct sk_buff *skb)
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -364,33 +364,37 @@ static netdev_tx_t clip_start_xmit(struc
 				   struct net_device *dev)
 {
 	struct clip_priv *clip_priv = PRIV(dev);
+	struct dst_entry *dst = skb_dst(skb);
 	struct atmarp_entry *entry;
+	struct neighbour *n;
 	struct atm_vcc *vcc;
 	int old;
 	unsigned long flags;
 
 	pr_debug("(skb %p)\n", skb);
-	if (!skb_dst(skb)) {
+	if (!dst) {
 		pr_err("skb_dst(skb) == NULL\n");
 		dev_kfree_skb(skb);
 		dev->stats.tx_dropped++;
 		return NETDEV_TX_OK;
 	}
-	if (!skb_dst(skb)->neighbour) {
+	n = dst_get_neighbour(dst);
+	if (!n) {
 #if 0
-		skb_dst(skb)->neighbour = clip_find_neighbour(skb_dst(skb), 1);
-		if (!skb_dst(skb)->neighbour) {
+		n = clip_find_neighbour(skb_dst(skb), 1);
+		if (!n) {
 			dev_kfree_skb(skb);	/* lost that one */
 			dev->stats.tx_dropped++;
 			return 0;
 		}
+		dst_set_neighbour(dst, n);
 #endif
 		pr_err("NO NEIGHBOUR !\n");
 		dev_kfree_skb(skb);
 		dev->stats.tx_dropped++;
 		return NETDEV_TX_OK;
 	}
-	entry = NEIGH2ENTRY(skb_dst(skb)->neighbour);
+	entry = NEIGH2ENTRY(n);
 	if (!entry->vccs) {
 		if (time_after(jiffies, entry->expires)) {
 			/* should be resolved */
@@ -407,7 +411,7 @@ static netdev_tx_t clip_start_xmit(struc
 	}
 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
-	pr_debug("using neighbour %p, vcc %p\n", skb_dst(skb)->neighbour, vcc);
+	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
 	if (entry->vccs->encap) {
 		void *here;
 
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -343,24 +343,26 @@ static int br_nf_pre_routing_finish_ipv6
 static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
 {
 	struct nf_bridge_info *nf_bridge = skb->nf_bridge;
+	struct neighbour *neigh;
 	struct dst_entry *dst;
 
 	skb->dev = bridge_parent(skb->dev);
 	if (!skb->dev)
 		goto free_skb;
 	dst = skb_dst(skb);
+	neigh = dst_get_neighbour(dst);
 	if (dst->hh) {
 		neigh_hh_bridge(dst->hh, skb);
 		skb->dev = nf_bridge->physindev;
 		return br_handle_frame_finish(skb);
-	} else if (dst->neighbour) {
+	} else if (neigh) {
 		/* the neighbour function below overwrites the complete
 		 * MAC header, so we save the Ethernet source address and
 		 * protocol number. */
 		skb_copy_from_linear_data_offset(skb, -(ETH_HLEN-ETH_ALEN), skb->nf_bridge->data, ETH_HLEN-ETH_ALEN);
 		/* tell br_dev_xmit to continue with forwarding */
 		nf_bridge->mask |= BRNF_BRIDGED_DNAT;
-		return dst->neighbour->output(skb);
+		return neigh->output(skb);
 	}
 free_skb:
 	kfree_skb(skb);
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -171,7 +171,7 @@ void *dst_alloc(struct dst_ops *ops, str
 	dst_init_metrics(dst, dst_default_metrics, true);
 	dst->expires = 0UL;
 	dst->path = dst;
-	dst->neighbour = NULL;
+	RCU_INIT_POINTER(dst->_neighbour, NULL);
 	dst->hh = NULL;
 #ifdef CONFIG_XFRM
 	dst->xfrm = NULL;
@@ -231,7 +231,7 @@ struct dst_entry *dst_destroy(struct dst
 	smp_rmb();
 
 again:
-	neigh = dst->neighbour;
+	neigh = rcu_dereference_protected(dst->_neighbour, 1);
 	hh = dst->hh;
 	child = dst->child;
 
@@ -240,7 +240,7 @@ again:
 		hh_cache_put(hh);
 
 	if (neigh) {
-		dst->neighbour = NULL;
+		RCU_INIT_POINTER(dst->_neighbour, NULL);
 		neigh_release(neigh);
 	}
 
@@ -367,14 +367,19 @@ static void dst_ifdown(struct dst_entry
 	if (!unregister) {
 		dst->input = dst->output = dst_discard;
 	} else {
+		struct neighbour *neigh;
+
 		dst->dev = dev_net(dst->dev)->loopback_dev;
 		dev_hold(dst->dev);
 		dev_put(dev);
-		if (dst->neighbour && dst->neighbour->dev == dev) {
-			dst->neighbour->dev = dst->dev;
+		rcu_read_lock();
+		neigh = dst_get_neighbour(dst);
+		if (neigh && neigh->dev == dev) {
+			neigh->dev = dst->dev;
 			dev_hold(dst->dev);
 			dev_put(dev);
 		}
+		rcu_read_unlock();
 	}
 }
 
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1173,12 +1173,17 @@ int neigh_update(struct neighbour *neigh
 
 		while (neigh->nud_state & NUD_VALID &&
 		       (skb = __skb_dequeue(&neigh->arp_queue)) != NULL) {
-			struct neighbour *n1 = neigh;
+			struct dst_entry *dst = skb_dst(skb);
+			struct neighbour *n2, *n1 = neigh;
 			write_unlock_bh(&neigh->lock);
+
+			rcu_read_lock();
 			/* On shaper/eql skb->dst->neighbour != neigh :( */
-			if (skb_dst(skb) && skb_dst(skb)->neighbour)
-				n1 = skb_dst(skb)->neighbour;
+			if (dst && (n2 = dst_get_neighbour(dst)) != NULL)
+				n1 = n2;
 			n1->output(skb);
+			rcu_read_unlock();
+
 			write_lock_bh(&neigh->lock);
 		}
 		skb_queue_purge(&neigh->arp_queue);
@@ -1300,10 +1305,10 @@ EXPORT_SYMBOL(neigh_compat_output);
 int neigh_resolve_output(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct neighbour *neigh;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	int rc = 0;
 
-	if (!dst || !(neigh = dst->neighbour))
+	if (!dst)
 		goto discard;
 
 	__skb_pull(skb, skb_network_offset(skb));
@@ -1333,7 +1338,7 @@ out:
 	return rc;
 discard:
 	NEIGH_PRINTK1("neigh_resolve_output: dst=%p neigh=%p\n",
-		      dst, dst ? dst->neighbour : NULL);
+		      dst, neigh);
 out_kfree_skb:
 	rc = -EINVAL;
 	kfree_skb(skb);
@@ -1347,7 +1352,7 @@ int neigh_connected_output(struct sk_buf
 {
 	int err;
 	struct dst_entry *dst = skb_dst(skb);
-	struct neighbour *neigh = dst->neighbour;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	struct net_device *dev = neigh->dev;
 	unsigned int seq;
 
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -208,7 +208,7 @@ static int dn_neigh_output_packet(struct
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct dn_route *rt = (struct dn_route *)dst;
-	struct neighbour *neigh = dst->neighbour;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	struct net_device *dev = neigh->dev;
 	char mac_addr[ETH_ALEN];
 
@@ -227,7 +227,7 @@ static int dn_neigh_output_packet(struct
 static int dn_long_output(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct neighbour *neigh = dst->neighbour;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 	unsigned char *data;
@@ -274,7 +274,7 @@ static int dn_long_output(struct sk_buff
 static int dn_short_output(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct neighbour *neigh = dst->neighbour;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 	struct dn_short_packet *sp;
@@ -318,7 +318,7 @@ static int dn_short_output(struct sk_buf
 static int dn_phase3_output(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct neighbour *neigh = dst->neighbour;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 	struct dn_short_packet *sp;
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -241,9 +241,11 @@ static int dn_dst_gc(struct dst_ops *ops
  */
 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 {
+	struct neighbour *n = dst_get_neighbour(dst);
 	u32 min_mtu = 230;
-	struct dn_dev *dn = dst->neighbour ?
-			    rcu_dereference_raw(dst->neighbour->dev->dn_ptr) : NULL;
+	struct dn_dev *dn;
+
+	dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
 
 	if (dn && dn->use_long == 0)
 		min_mtu -= 6;
@@ -715,7 +717,7 @@ static int dn_output(struct sk_buff *skb
 
 	int err = -EINVAL;
 
-	if ((neigh = dst->neighbour) == NULL)
+	if ((neigh = dst_get_neighbour(dst)) == NULL)
 		goto error;
 
 	skb->dev = dev;
@@ -750,7 +752,7 @@ static int dn_forward(struct sk_buff *sk
 	struct dst_entry *dst = skb_dst(skb);
 	struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 	struct dn_route *rt;
-	struct neighbour *neigh = dst->neighbour;
+	struct neighbour *neigh = dst_get_neighbour(dst);
 	int header_len;
 #ifdef CONFIG_NETFILTER
 	struct net_device *dev = skb->dev;
@@ -833,11 +835,11 @@ static int dn_rt_set_next_hop(struct dn_
 	}
 	rt->rt_type = res->type;
 
-	if (dev != NULL && rt->dst.neighbour == NULL) {
+	if (dev != NULL && dst_get_neighbour(&rt->dst) == NULL) {
 		n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 		if (IS_ERR(n))
 			return PTR_ERR(n);
-		rt->dst.neighbour = n;
+		dst_set_neighbour(&rt->dst, n);
 	}
 
 	if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
@@ -1144,7 +1146,7 @@ make_route:
 	rt->rt_dst_map    = fld.daddr;
 	rt->rt_src_map    = fld.saddr;
 
-	rt->dst.neighbour = neigh;
+	dst_set_neighbour(&rt->dst, neigh);
 	neigh = NULL;
 
 	rt->dst.lastuse = jiffies;
@@ -1416,7 +1418,7 @@ make_route:
 	rt->fld.flowidn_iif  = in_dev->ifindex;
 	rt->fld.flowidn_mark = fld.flowidn_mark;
 
-	rt->dst.neighbour = neigh;
+	dst_set_neighbour(&rt->dst, neigh);
 	rt->dst.lastuse = jiffies;
 	rt->dst.output = dn_rt_bug;
 	switch(res.type) {
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -518,26 +518,32 @@ EXPORT_SYMBOL(arp_find);
 
 /* END OF OBSOLETE FUNCTIONS */
 
+struct neighbour *__arp_bind_neighbour(struct dst_entry *dst, __be32 nexthop)
+{
+	struct net_device *dev = dst->dev;
+
+	if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
+		nexthop = 0;
+	return __neigh_lookup_errno(
+#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
+		dev->type == ARPHRD_ATM ?
+		clip_tbl_hook :
+#endif
+		&arp_tbl, &nexthop, dev);
+}
+
 int arp_bind_neighbour(struct dst_entry *dst)
 {
 	struct net_device *dev = dst->dev;
-	struct neighbour *n = dst->neighbour;
+	struct neighbour *n = dst_get_neighbour(dst);
 
 	if (dev == NULL)
 		return -EINVAL;
 	if (n == NULL) {
-		__be32 nexthop = ((struct rtable *)dst)->rt_gateway;
-		if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
-			nexthop = 0;
-		n = __neigh_lookup_errno(
-#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
-					 dev->type == ARPHRD_ATM ?
-					 clip_tbl_hook :
-#endif
-					 &arp_tbl, &nexthop, dev);
+		n = __arp_bind_neighbour(dst, ((struct rtable *)dst)->rt_gateway);
 		if (IS_ERR(n))
 			return PTR_ERR(n);
-		dst->neighbour = n;
+		dst_set_neighbour(dst, n);
 	}
 	return 0;
 }
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -731,9 +731,9 @@ static netdev_tx_t ipgre_tunnel_xmit(str
 		}
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 		else if (skb->protocol == htons(ETH_P_IPV6)) {
+			struct neighbour *neigh = dst_get_neighbour(skb_dst(skb));
 			const struct in6_addr *addr6;
 			int addr_type;
-			struct neighbour *neigh = skb_dst(skb)->neighbour;
 
 			if (neigh == NULL)
 				goto tx_error;
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -182,6 +182,8 @@ static inline int ip_finish_output2(stru
 	struct rtable *rt = (struct rtable *)dst;
 	struct net_device *dev = dst->dev;
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
+	struct neighbour *neigh;
+	int res;
 
 	if (rt->rt_type == RTN_MULTICAST) {
 		IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len);
@@ -202,11 +204,23 @@ static inline int ip_finish_output2(stru
 		kfree_skb(skb);
 		skb = skb2;
 	}
+
+	rcu_read_lock();
+	if (dst->hh) {
+		int res = neigh_hh_output(dst->hh, skb);
 
-	if (dst->hh)
-		return neigh_hh_output(dst->hh, skb);
-	else if (dst->neighbour)
-		return dst->neighbour->output(skb);
+		rcu_read_unlock();
+		return res;
+	} else {
+		neigh = dst_get_neighbour(dst);
+		if (neigh) {
+			res = neigh->output(skb);
+
+			rcu_read_unlock();
+			return res;
+		}
+		rcu_read_unlock();
+	}
 
 	if (net_ratelimit())
 		printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n");
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -416,7 +416,13 @@ static int rt_cache_seq_show(struct seq_
 			   "HHUptod\tSpecDst");
 	else {
 		struct rtable *r = v;
-		int len;
+		struct neighbour *n;
+		int len, HHUptod;
+
+		rcu_read_lock();
+		n = dst_get_neighbour(&r->dst);
+		HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0;
+		rcu_read_unlock();
 
 		seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
 			      "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
@@ -431,8 +437,7 @@ static int rt_cache_seq_show(struct seq_
 			      dst_metric(&r->dst, RTAX_RTTVAR)),
 			r->rt_key_tos,
 			r->dst.hh ? atomic_read(&r->dst.hh->hh_refcnt) : -1,
-			r->dst.hh ? (r->dst.hh->hh_output ==
-				       dev_queue_xmit) : 0,
+			HHUptod,
 			r->rt_spec_dst, &len);
 
 		seq_printf(seq, "%*s\n", 127 - len, "");
@@ -1688,23 +1693,25 @@ static int check_peer_redir(struct dst_e
 {
 	struct rtable *rt = (struct rtable *) dst;
 	__be32 orig_gw = rt->rt_gateway;
+	struct neighbour *n, *old_n;
 
 	dst_confirm(&rt->dst);
 
-	neigh_release(rt->dst.neighbour);
-	rt->dst.neighbour = NULL;
-
 	rt->rt_gateway = peer->redirect_learned.a4;
-	if (arp_bind_neighbour(&rt->dst) ||
-	    !(rt->dst.neighbour->nud_state & NUD_VALID)) {
-		if (rt->dst.neighbour)
-			neigh_event_send(rt->dst.neighbour, NULL);
+	n = __arp_bind_neighbour(&rt->dst, rt->rt_gateway);
+	if (IS_ERR(n))
+		return PTR_ERR(n);
+	old_n = xchg(&rt->dst._neighbour, n);
+	if (old_n)
+		neigh_release(old_n);
+	if (!n || !(n->nud_state & NUD_VALID)) {
+		if (n)
+			neigh_event_send(n, NULL);
 		rt->rt_gateway = orig_gw;
 		return -EAGAIN;
 	} else {
 		rt->rt_flags |= RTCF_REDIRECTED;
-		call_netevent_notifiers(NETEVENT_NEIGH_UPDATE,
-					rt->dst.neighbour);
+		call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 	}
 	return 0;
 }
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -656,7 +656,7 @@ ipv6_add_addr(struct inet6_dev *idev, co
 	 * layer address of our nexhop router
 	 */
 
-	if (rt->rt6i_nexthop == NULL)
+	if (dst_get_neighbour_raw(&rt->dst) == NULL)
 		ifa->flags &= ~IFA_F_OPTIMISTIC;
 
 	ifa->idev = idev;
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1455,7 +1455,7 @@ static int fib6_age(struct rt6_info *rt,
 			RT6_TRACE("aging clone %p\n", rt);
 			return -1;
 		} else if ((rt->rt6i_flags & RTF_GATEWAY) &&
-			   (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
+			   (!(dst_get_neighbour_raw(&rt->dst)->flags & NTF_ROUTER))) {
 			RT6_TRACE("purging route %p via non-router but gateway\n",
 				  rt);
 			return -1;
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -100,6 +100,8 @@ static int ip6_finish_output2(struct sk_
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct net_device *dev = dst->dev;
+	struct neighbour *neigh;
+	int res;
 
 	skb->protocol = htons(ETH_P_IPV6);
 	skb->dev = dev;
@@ -134,10 +136,22 @@ static int ip6_finish_output2(struct sk_
 				skb->len);
 	}
 
-	if (dst->hh)
-		return neigh_hh_output(dst->hh, skb);
-	else if (dst->neighbour)
-		return dst->neighbour->output(skb);
+	rcu_read_lock();
+	if (dst->hh) {
+		res = neigh_hh_output(dst->hh, skb);
+
+		rcu_read_unlock();
+		return res;
+	} else {
+		neigh = dst_get_neighbour(dst);
+		if (neigh) {
+			res = neigh->output(skb);
+
+			rcu_read_unlock();
+			return res;
+		}
+		rcu_read_unlock();
+	}
 
 	IP6_INC_STATS_BH(dev_net(dst->dev),
 			 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
@@ -385,6 +399,7 @@ int ip6_forward(struct sk_buff *skb)
 	struct ipv6hdr *hdr = ipv6_hdr(skb);
 	struct inet6_skb_parm *opt = IP6CB(skb);
 	struct net *net = dev_net(dst->dev);
+	struct neighbour *n;
 	u32 mtu;
 
 	if (net->ipv6.devconf_all->forwarding == 0)
@@ -459,11 +474,10 @@ int ip6_forward(struct sk_buff *skb)
 	   send redirects to source routed frames.
 	   We don't send redirects to frames decapsulated from IPsec.
 	 */
-	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0 &&
-	    !skb_sec_path(skb)) {
+	n = dst_get_neighbour(dst);
+	if (skb->dev == dst->dev && n && opt->srcrt == 0 && !skb_sec_path(skb)) {
 		struct in6_addr *target = NULL;
 		struct rt6_info *rt;
-		struct neighbour *n = dst->neighbour;
 
 		/*
 		 *	incoming and outgoing devices are the same
@@ -949,8 +963,11 @@ out:
 static int ip6_dst_lookup_tail(struct sock *sk,
 			       struct dst_entry **dst, struct flowi6 *fl6)
 {
-	int err;
 	struct net *net = sock_net(sk);
+#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
+	struct neighbour *n;
+#endif
+	int err;
 
 	if (*dst == NULL)
 		*dst = ip6_route_output(net, sk, fl6);
@@ -976,11 +993,14 @@ static int ip6_dst_lookup_tail(struct so
 	 * dst entry and replace it instead with the
 	 * dst entry of the nexthop router
 	 */
-	if ((*dst)->neighbour && !((*dst)->neighbour->nud_state & NUD_VALID)) {
+	rcu_read_lock();
+	n = dst_get_neighbour(*dst);
+	if (n && !(n->nud_state & NUD_VALID)) {
 		struct inet6_ifaddr *ifp;
 		struct flowi6 fl_gw6;
 		int redirect;
 
+		rcu_read_unlock();
 		ifp = ipv6_get_ifaddr(net, &fl6->saddr,
 				      (*dst)->dev, 1);
 
@@ -1000,6 +1020,8 @@ static int ip6_dst_lookup_tail(struct so
 			if ((err = (*dst)->error))
 				goto out_err_release;
 		}
+	} else {
+		rcu_read_unlock();
 	}
 #endif
 
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1244,7 +1244,7 @@ static void ndisc_router_discovery(struc
 	rt = rt6_get_dflt_router(&ipv6_hdr(skb)->saddr, skb->dev);
 
 	if (rt)
-		neigh = rt->rt6i_nexthop;
+		neigh = dst_get_neighbour(&rt->dst);
 
 	if (rt && lifetime == 0) {
 		neigh_clone(neigh);
@@ -1265,7 +1265,7 @@ static void ndisc_router_discovery(struc
 			return;
 		}
 
-		neigh = rt->rt6i_nexthop;
+		neigh = dst_get_neighbour(&rt->dst);
 		if (neigh == NULL) {
 			ND_PRINTK0(KERN_ERR
 				   "ICMPv6 RA: %s() got default router without neighbour.\n",
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -356,7 +356,7 @@ out:
 #ifdef CONFIG_IPV6_ROUTER_PREF
 static void rt6_probe(struct rt6_info *rt)
 {
-	struct neighbour *neigh = rt ? rt->rt6i_nexthop : NULL;
+	struct neighbour *neigh;
 	/*
 	 * Okay, this does not seem to be appropriate
 	 * for now, however, we need to check if it
@@ -365,8 +365,10 @@ static void rt6_probe(struct rt6_info *r
 	 * Router Reachability Probe MUST be rate-limited
 	 * to no more than one per minute.
 	 */
+	rcu_read_lock();
+	neigh = rt ? dst_get_neighbour(&rt->dst) : NULL;
 	if (!neigh || (neigh->nud_state & NUD_VALID))
-		return;
+		goto out;
 	read_lock_bh(&neigh->lock);
 	if (!(neigh->nud_state & NUD_VALID) &&
 	    time_after(jiffies, neigh->updated + rt->rt6i_idev->cnf.rtr_probe_interval)) {
@@ -379,8 +381,11 @@ static void rt6_probe(struct rt6_info *r
 		target = (struct in6_addr *)&neigh->primary_key;
 		addrconf_addr_solict_mult(target, &mcaddr);
 		ndisc_send_ns(rt->rt6i_dev, NULL, target, &mcaddr, NULL);
-	} else
+	} else {
 		read_unlock_bh(&neigh->lock);
+	}
+out:
+	rcu_read_unlock();
 }
 #else
 static inline void rt6_probe(struct rt6_info *rt)
@@ -404,8 +409,11 @@ static inline int rt6_check_dev(struct r
 
 static inline int rt6_check_neigh(struct rt6_info *rt)
 {
-	struct neighbour *neigh = rt->rt6i_nexthop;
+	struct neighbour *neigh;
 	int m;
+
+	rcu_read_lock();
+	neigh = dst_get_neighbour(&rt->dst);
 	if (rt->rt6i_flags & RTF_NONEXTHOP ||
 	    !(rt->rt6i_flags & RTF_GATEWAY))
 		m = 1;
@@ -422,6 +430,7 @@ static inline int rt6_check_neigh(struct
 		read_unlock_bh(&neigh->lock);
 	} else
 		m = 0;
+	rcu_read_unlock();
 	return m;
 }
 
@@ -745,8 +754,7 @@ static struct rt6_info *rt6_alloc_cow(st
 			dst_free(&rt->dst);
 			return NULL;
 		}
-		rt->rt6i_nexthop = neigh;
-
+		dst_set_neighbour(&rt->dst, neigh);
 	}
 
 	return rt;
@@ -760,7 +768,7 @@ static struct rt6_info *rt6_alloc_clone(
 		rt->rt6i_dst.plen = 128;
 		rt->rt6i_flags |= RTF_CACHE;
 		rt->dst.flags |= DST_HOST;
-		rt->rt6i_nexthop = neigh_clone(ort->rt6i_nexthop);
+		dst_set_neighbour(&rt->dst, neigh_clone(dst_get_neighbour_raw(&ort->dst)));
 	}
 	return rt;
 }
@@ -794,7 +802,7 @@ restart:
 	dst_hold(&rt->dst);
 	read_unlock_bh(&table->tb6_lock);
 
-	if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
+	if (!dst_get_neighbour_raw(&rt->dst) && !(rt->rt6i_flags & RTF_NONEXTHOP))
 		nrt = rt6_alloc_cow(rt, &fl6->daddr, &fl6->saddr);
 	else if (!(rt->dst.flags & DST_HOST))
 		nrt = rt6_alloc_clone(rt, &fl6->daddr);
@@ -1058,7 +1066,7 @@ struct dst_entry *icmp6_dst_alloc(struct
 	}
 
 	rt->rt6i_idev     = idev;
-	rt->rt6i_nexthop  = neigh;
+	dst_set_neighbour(&rt->dst, neigh);
 	atomic_set(&rt->dst.__refcnt, 1);
 	dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 255);
 	rt->dst.output  = ip6_output;
@@ -1338,12 +1346,12 @@ int ip6_route_add(struct fib6_config *cf
 		rt->rt6i_prefsrc.plen = 0;
 
 	if (cfg->fc_flags & (RTF_GATEWAY | RTF_NONEXTHOP)) {
-		rt->rt6i_nexthop = __neigh_lookup_errno(&nd_tbl, &rt->rt6i_gateway, dev);
-		if (IS_ERR(rt->rt6i_nexthop)) {
-			err = PTR_ERR(rt->rt6i_nexthop);
-			rt->rt6i_nexthop = NULL;
+		struct neighbour *neigh = __neigh_lookup_errno(&nd_tbl, &rt->rt6i_gateway, dev);
+		if (IS_ERR(neigh)) {
+			err = PTR_ERR(neigh);
 			goto out;
 		}
+		dst_set_neighbour(&rt->dst, neigh);
 	}
 
 	rt->rt6i_flags = cfg->fc_flags;
@@ -1574,7 +1582,7 @@ void rt6_redirect(const struct in6_addr
 	dst_confirm(&rt->dst);
 
 	/* Duplicate redirect: silently ignore. */
-	if (neigh == rt->dst.neighbour)
+	if (neigh == dst_get_neighbour_raw(&rt->dst))
 		goto out;
 
 	nrt = ip6_rt_copy(rt);
@@ -1590,7 +1598,7 @@ void rt6_redirect(const struct in6_addr
 	nrt->dst.flags |= DST_HOST;
 
 	ipv6_addr_copy(&nrt->rt6i_gateway, (struct in6_addr*)neigh->primary_key);
-	nrt->rt6i_nexthop = neigh_clone(neigh);
+	dst_set_neighbour(&nrt->dst, neigh_clone(neigh));
 
 	if (ip6_ins_rt(nrt))
 		goto out;
@@ -1670,7 +1678,7 @@ again:
 	   1. It is connected route. Action: COW
 	   2. It is gatewayed route or NONEXTHOP route. Action: clone it.
 	 */
-	if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
+	if (!dst_get_neighbour_raw(&rt->dst) && !(rt->rt6i_flags & RTF_NONEXTHOP))
 		nrt = rt6_alloc_cow(rt, daddr, saddr);
 	else
 		nrt = rt6_alloc_clone(rt, daddr);
@@ -2035,7 +2043,7 @@ struct rt6_info *addrconf_dst_alloc(stru
 
 		return ERR_CAST(neigh);
 	}
-	rt->rt6i_nexthop = neigh;
+	dst_set_neighbour(&rt->dst, neigh);
 
 	ipv6_addr_copy(&rt->rt6i_dst.addr, addr);
 	rt->rt6i_dst.plen = 128;
@@ -2312,6 +2320,7 @@ static int rt6_fill_node(struct net *net
 	struct nlmsghdr *nlh;
 	long expires;
 	u32 table;
+	struct neighbour *n;
 
 	if (prefix) {	/* user wants prefix routes only */
 		if (!(rt->rt6i_flags & RTF_PREFIX_RT)) {
@@ -2400,8 +2409,11 @@ static int rt6_fill_node(struct net *net
 	if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
 		goto nla_put_failure;
 
-	if (rt->dst.neighbour)
-		NLA_PUT(skb, RTA_GATEWAY, 16, &rt->dst.neighbour->primary_key);
+	rcu_read_lock();
+	n = dst_get_neighbour(&rt->dst);
+	if (n)
+		NLA_PUT(skb, RTA_GATEWAY, 16, &n->primary_key);
+	rcu_read_unlock();
 
 	if (rt->dst.dev)
 		NLA_PUT_U32(skb, RTA_OIF, rt->rt6i_dev->ifindex);
@@ -2585,6 +2597,7 @@ struct rt6_proc_arg
 static int rt6_info_route(struct rt6_info *rt, void *p_arg)
 {
 	struct seq_file *m = p_arg;
+	struct neighbour *n;
 
 	seq_printf(m, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
 
@@ -2593,12 +2606,14 @@ static int rt6_info_route(struct rt6_inf
 #else
 	seq_puts(m, "00000000000000000000000000000000 00 ");
 #endif
-
-	if (rt->rt6i_nexthop) {
-		seq_printf(m, "%pi6", rt->rt6i_nexthop->primary_key);
+	rcu_read_lock();
+	n = dst_get_neighbour(&rt->dst);
+	if (n) {
+		seq_printf(m, "%pi6", n->primary_key);
 	} else {
 		seq_puts(m, "00000000000000000000000000000000");
 	}
+	rcu_read_unlock();
 	seq_printf(m, " %08x %08x %08x %08x %8s\n",
 		   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
 		   rt->dst.__use, rt->rt6i_flags,
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -679,7 +679,7 @@ static netdev_tx_t ipip6_tunnel_xmit(str
 		struct neighbour *neigh = NULL;
 
 		if (skb_dst(skb))
-			neigh = skb_dst(skb)->neighbour;
+			neigh = dst_get_neighbour(skb_dst(skb));
 
 		if (neigh == NULL) {
 			if (net_ratelimit())
@@ -704,7 +704,7 @@ static netdev_tx_t ipip6_tunnel_xmit(str
 		struct neighbour *neigh = NULL;
 
 		if (skb_dst(skb))
-			neigh = skb_dst(skb)->neighbour;
+			neigh = dst_get_neighbour(skb_dst(skb));
 
 		if (neigh == NULL) {
 			if (net_ratelimit())
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -225,11 +225,11 @@ static int teql_qdisc_init(struct Qdisc
 
 
 static int
-__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
+__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
+	       struct net_device *dev, struct netdev_queue *txq,
+	       struct neighbour *mn)
 {
-	struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
-	struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
-	struct neighbour *mn = skb_dst(skb)->neighbour;
+	struct teql_sched_data *q = qdisc_priv(txq->qdisc);
 	struct neighbour *n = q->ncache;
 
 	if (mn->tbl == NULL)
@@ -262,17 +262,26 @@ __teql_resolve(struct sk_buff *skb, stru
 }
 
 static inline int teql_resolve(struct sk_buff *skb,
-			       struct sk_buff *skb_res, struct net_device *dev)
+			       struct sk_buff *skb_res,
+			       struct net_device *dev,
+			       struct netdev_queue *txq)
 {
-	struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
+	struct dst_entry *dst = skb_dst(skb);
+	struct neighbour *mn;
+	int res;
+
 	if (txq->qdisc == &noop_qdisc)
 		return -ENODEV;
 
-	if (dev->header_ops == NULL ||
-	    skb_dst(skb) == NULL ||
-	    skb_dst(skb)->neighbour == NULL)
+	if (!dev->header_ops || !dst)
 		return 0;
-	return __teql_resolve(skb, skb_res, dev);
+
+	rcu_read_lock();
+	mn = dst_get_neighbour(dst);
+	res = mn ? __teql_resolve(skb, skb_res, dev, txq, mn) : 0;
+	rcu_read_unlock();
+
+	return res;
 }
 
 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -307,7 +316,7 @@ restart:
 			continue;
 		}
 
-		switch (teql_resolve(skb, skb_res, slave)) {
+		switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
 		case 0:
 			if (__netif_tx_trylock(slave_txq)) {
 				unsigned int length = qdisc_pkt_len(skb);
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1497,7 +1497,7 @@ static struct dst_entry *xfrm_bundle_cre
 		goto free_dst;
 
 	/* Copy neighbour for reachability confirmation */
-	dst0->neighbour = neigh_clone(dst->neighbour);
+	dst_set_neighbour(dst0, neigh_clone(dst_get_neighbour(dst)));
 
 	xfrm_init_path((struct xfrm_dst *)dst0, dst, nfheader_len);
 	xfrm_init_pmtu(dst_prev);