From 02581e536c3e62cedb465fd101b61b9142e87adb Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Fri, 20 Jun 2008 22:16:51 -0700
Subject: [PATCH] --- yaml --- r: 98367 b: refs/heads/master c:
 b9f75f45a6b46a0ab4eb0857d437a0845871f314 h: refs/heads/master i:   98365:
 f79468a952b98e3300bf2a8ec25b9dd978a6df64   98363:
 9c5454a4717116db9bd17f34b78726bde6fb4b15   98359:
 141e1489b26cbf9a0e7879c00bcf72ecffd5688e   98351:
 a1cfff810ed2c485fd8285e942aea1d3cd13b01a   98335:
 741e0d1f6a9015bd2db21426a27b634767960f18   98303:
 8d3fd52306c01a77327e5a8547cc363fa60bb45f v: v3

---
 [refs]                            |  2 +-
 trunk/include/net/net_namespace.h | 11 +++++++++++
 trunk/net/core/dev.c              |  4 ++++
 trunk/net/core/net_namespace.c    |  3 +++
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 545e2a01e0be..fac6026a7c77 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 735ce972fbc8a65fb17788debd7bbe7b4383cc62
+refs/heads/master: b9f75f45a6b46a0ab4eb0857d437a0845871f314
diff --git a/trunk/include/net/net_namespace.h b/trunk/include/net/net_namespace.h
index aa540e6be502..d9dd0f707296 100644
--- a/trunk/include/net/net_namespace.h
+++ b/trunk/include/net/net_namespace.h
@@ -95,6 +95,11 @@ extern struct list_head net_namespace_list;
 #ifdef CONFIG_NET_NS
 extern void __put_net(struct net *net);
 
+static inline int net_alive(struct net *net)
+{
+	return net && atomic_read(&net->count);
+}
+
 static inline struct net *get_net(struct net *net)
 {
 	atomic_inc(&net->count);
@@ -125,6 +130,12 @@ int net_eq(const struct net *net1, const struct net *net2)
 	return net1 == net2;
 }
 #else
+
+static inline int net_alive(struct net *net)
+{
+	return 1;
+}
+
 static inline struct net *get_net(struct net *net)
 {
 	return net;
diff --git a/trunk/net/core/dev.c b/trunk/net/core/dev.c
index 68d8df0992ab..c421a1f8f0b9 100644
--- a/trunk/net/core/dev.c
+++ b/trunk/net/core/dev.c
@@ -2077,6 +2077,10 @@ int netif_receive_skb(struct sk_buff *skb)
 
 	rcu_read_lock();
 
+	/* Don't receive packets in an exiting network namespace */
+	if (!net_alive(dev_net(skb->dev)))
+		goto out;
+
 #ifdef CONFIG_NET_CLS_ACT
 	if (skb->tc_verd & TC_NCLS) {
 		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
diff --git a/trunk/net/core/net_namespace.c b/trunk/net/core/net_namespace.c
index 72b4c184dd84..7c52fe277b62 100644
--- a/trunk/net/core/net_namespace.c
+++ b/trunk/net/core/net_namespace.c
@@ -140,6 +140,9 @@ static void cleanup_net(struct work_struct *work)
 	struct pernet_operations *ops;
 	struct net *net;
 
+	/* Be very certain incoming network packets will not find us */
+	rcu_barrier();
+
 	net = container_of(work, struct net, work);
 
 	mutex_lock(&net_mutex);