diff --git a/include/net/sock.h b/include/net/sock.h
index d200dfb..0bea25d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -363,6 +363,27 @@ static __inline__ int sk_del_node_init(struct sock *sk)
 	return rc;
 }
 
+static __inline__ int __sk_del_node_init_rcu(struct sock *sk)
+{
+	if (sk_hashed(sk)) {
+		hlist_del_init_rcu(&sk->sk_node);
+		return 1;
+	}
+	return 0;
+}
+
+static __inline__ int sk_del_node_init_rcu(struct sock *sk)
+{
+	int rc = __sk_del_node_init_rcu(sk);
+
+	if (rc) {
+		/* paranoid for a while -acme */
+		WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
+		__sock_put(sk);
+	}
+	return rc;
+}
+
 static __inline__ void __sk_add_node(struct sock *sk, struct hlist_head *list)
 {
 	hlist_add_head(&sk->sk_node, list);
@@ -374,6 +395,17 @@ static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list)
 	__sk_add_node(sk, list);
 }
 
+static __inline__ void __sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
+{
+	hlist_add_head_rcu(&sk->sk_node, list);
+}
+
+static __inline__ void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
+{
+	sock_hold(sk);
+	__sk_add_node_rcu(sk, list);
+}
+
 static __inline__ void __sk_del_bind_node(struct sock *sk)
 {
 	__hlist_del(&sk->sk_bind_node);
@@ -387,6 +419,8 @@ static __inline__ void sk_add_bind_node(struct sock *sk,
 
 #define sk_for_each(__sk, node, list) \
 	hlist_for_each_entry(__sk, node, list, sk_node)
+#define sk_for_each_rcu(__sk, node, list) \
+	hlist_for_each_entry_rcu(__sk, node, list, sk_node)
 #define sk_for_each_from(__sk, node) \
 	if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
 		hlist_for_each_entry_from(__sk, node, sk_node)
@@ -589,8 +623,9 @@ struct proto {
 	int			*sysctl_rmem;
 	int			max_header;
 
-	struct kmem_cache		*slab;
+	struct kmem_cache	*slab;
 	unsigned int		obj_size;
+	int			slab_flags;
 
 	atomic_t		*orphan_count;
 
diff --git a/net/core/sock.c b/net/core/sock.c
index 5e2a313..ded1eb5 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2042,7 +2042,8 @@ int proto_register(struct proto *prot, int alloc_slab)
 
 	if (alloc_slab) {
 		prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
-					       SLAB_HWCACHE_ALIGN, NULL);
+					SLAB_HWCACHE_ALIGN | prot->slab_flags,
+					NULL);
 
 		if (prot->slab == NULL) {
 			printk(KERN_CRIT "%s: Can't create sock SLAB cache!\n",
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b91cd0a..5c1cbe1 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -187,7 +187,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
 	inet_sk(sk)->num = snum;
 	sk->sk_hash = snum;
 	if (sk_unhashed(sk)) {
-		sk_add_node(sk, &hslot->head);
+		sk_add_node_rcu(sk, &hslot->head);
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	}
 	error = 0;
@@ -253,15 +253,24 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 		__be16 sport, __be32 daddr, __be16 dport,
 		int dif, struct udp_table *udptable)
 {
-	struct sock *sk, *result = NULL;
+	struct sock *sk, *result;
 	struct hlist_node *node;
 	unsigned short hnum = ntohs(dport);
 	unsigned int hash = udp_hashfn(net, hnum);
 	struct udp_hslot *hslot = &udptable->hash[hash];
-	int score, badness = -1;
+	int score, badness;
 
-	spin_lock(&hslot->lock);
-	sk_for_each(sk, node, &hslot->head) {
+	rcu_read_lock();
+begin:
+	result = NULL;
+	badness = -1;
+	sk_for_each_rcu(sk, node, &hslot->head) {
+		/*
+		 * lockless reader, and SLAB_DESTROY_BY_RCU items:
+		 * We must check this item was not moved to another chain
+		 */
+		if (udp_hashfn(net, sk->sk_hash) != hash)
+			goto begin;
 		score = compute_score(sk, net, saddr, hnum, sport,
 				      daddr, dport, dif);
 		if (score > badness) {
@@ -269,9 +278,16 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 			badness = score;
  		}
 	}
-	if (result)
-		sock_hold(result);
-	spin_unlock(&hslot->lock);
+	if (result) {
+		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+			result = NULL;
+		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
+				  daddr, dport, dif) < badness)) {
+			sock_put(result);
+			goto begin;
+		}
+	}
+	rcu_read_unlock();
 	return result;
 }
 
@@ -953,7 +969,7 @@ void udp_lib_unhash(struct sock *sk)
 	struct udp_hslot *hslot = &udptable->hash[hash];
 
 	spin_lock(&hslot->lock);
-	if (sk_del_node_init(sk)) {
+	if (sk_del_node_init_rcu(sk)) {
 		inet_sk(sk)->num = 0;
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	}
@@ -1517,6 +1533,7 @@ struct proto udp_prot = {
 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
 	.obj_size	   = sizeof(struct udp_sock),
+	.slab_flags	   = SLAB_DESTROY_BY_RCU,
 	.h.udp_table	   = &udp_table,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_udp_setsockopt,
diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c
index d8ea8e5..c784891 100644
--- a/net/ipv4/udplite.c
+++ b/net/ipv4/udplite.c
@@ -51,6 +51,7 @@ struct proto 	udplite_prot = {
 	.unhash		   = udp_lib_unhash,
 	.get_port	   = udp_v4_get_port,
 	.obj_size	   = sizeof(struct udp_sock),
+	.slab_flags	   = SLAB_DESTROY_BY_RCU,
 	.h.udp_table	   = &udplite_table,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_udp_setsockopt,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ccee724..df78ddc 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -97,24 +97,40 @@ static struct sock *__udp6_lib_lookup(struct net *net,
 				      struct in6_addr *daddr, __be16 dport,
 				      int dif, struct udp_table *udptable)
 {
-	struct sock *sk, *result = NULL;
+	struct sock *sk, *result;
 	struct hlist_node *node;
 	unsigned short hnum = ntohs(dport);
 	unsigned int hash = udp_hashfn(net, hnum);
 	struct udp_hslot *hslot = &udptable->hash[hash];
-	int score, badness = -1;
+	int score, badness;
 
-	spin_lock(&hslot->lock);
-	sk_for_each(sk, node, &hslot->head) {
+	rcu_read_lock();
+begin:
+	result = NULL;
+	badness = -1;
+	sk_for_each_rcu(sk, node, &hslot->head) {
+		/*
+		 * lockless reader, and SLAB_DESTROY_BY_RCU items:
+		 * We must check this item was not moved to another chain
+		 */
+		if (udp_hashfn(net, sk->sk_hash) != hash)
+			goto begin;
 		score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
 		if (score > badness) {
 			result = sk;
 			badness = score;
 		}
 	}
-	if (result)
-		sock_hold(result);
-	spin_unlock(&hslot->lock);
+	if (result) {
+		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+			result = NULL;
+		else if (unlikely(compute_score(result, net, hnum, saddr, sport,
+					daddr, dport, dif) < badness)) {
+			sock_put(result);
+			goto begin;
+ 		}
+	}
+	rcu_read_unlock();
 	return result;
 }
 
@@ -1062,6 +1078,7 @@ struct proto udpv6_prot = {
 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
 	.obj_size	   = sizeof(struct udp6_sock),
+	.slab_flags	   = SLAB_DESTROY_BY_RCU,
 	.h.udp_table	   = &udp_table,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_udpv6_setsockopt,
diff --git a/net/ipv6/udplite.c b/net/ipv6/udplite.c
index f1e892a..05ab176 100644
--- a/net/ipv6/udplite.c
+++ b/net/ipv6/udplite.c
@@ -49,6 +49,7 @@ struct proto udplitev6_prot = {
 	.unhash		   = udp_lib_unhash,
 	.get_port	   = udp_v6_get_port,
 	.obj_size	   = sizeof(struct udp6_sock),
+ 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
 	.h.udp_table	   = &udplite_table,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_udpv6_setsockopt,