1 files changed, 37 insertions, 8 deletions

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 15f68842ac6b..e31ab1f9c91d 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -145,6 +145,17 @@ static void ops_free(const struct pernet_operations *ops, struct net *net)
 	}
 }
 
+static void ops_pre_exit_list(const struct pernet_operations *ops,
+			      struct list_head *net_exit_list)
+{
+	struct net *net;
+
+	if (ops->pre_exit) {
+		list_for_each_entry(net, net_exit_list, exit_list)
+			ops->pre_exit(net);
+	}
+}
+
 static void ops_exit_list(const struct pernet_operations *ops,
 			  struct list_head *net_exit_list)
 {
@@ -227,11 +238,11 @@ static int __peernet2id(struct net *net, struct net *peer)
 	return __peernet2id_alloc(net, peer, &no);
 }
 
-static void rtnl_net_notifyid(struct net *net, int cmd, int id);
+static void rtnl_net_notifyid(struct net *net, int cmd, int id, gfp_t gfp);
 /* This function returns the id of a peer netns. If no id is assigned, one will
  * be allocated and returned.
  */
-int peernet2id_alloc(struct net *net, struct net *peer)
+int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp)
 {
 	bool alloc = false, alive = false;
 	int id;
@@ -250,7 +261,7 @@ int peernet2id_alloc(struct net *net, struct net *peer)
 	id = __peernet2id_alloc(net, peer, &alloc);
 	spin_unlock_bh(&net->nsid_lock);
 	if (alloc && id >= 0)
-		rtnl_net_notifyid(net, RTM_NEWNSID, id);
+		rtnl_net_notifyid(net, RTM_NEWNSID, id, gfp);
 	if (alive)
 		put_net(peer);
 	return id;
@@ -330,6 +341,12 @@ out_undo:
 	list_add(&net->exit_list, &net_exit_list);
 	saved_ops = ops;
 	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
+		ops_pre_exit_list(ops, &net_exit_list);
+
+	synchronize_rcu();
+
+	ops = saved_ops;
+	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 		ops_exit_list(ops, &net_exit_list);
 
 	ops = saved_ops;
@@ -496,7 +513,8 @@ static void unhash_nsid(struct net *net, struct net *last)
 			idr_remove(&tmp->netns_ids, id);
 		spin_unlock_bh(&tmp->nsid_lock);
 		if (id >= 0)
-			rtnl_net_notifyid(tmp, RTM_DELNSID, id);
+			rtnl_net_notifyid(tmp, RTM_DELNSID, id,
+					  GFP_KERNEL);
 		if (tmp == last)
 			break;
 	}
@@ -541,10 +559,15 @@ static void cleanup_net(struct work_struct *work)
 		list_add_tail(&net->exit_list, &net_exit_list);
 	}
 
+	/* Run all of the network namespace pre_exit methods */
+	list_for_each_entry_reverse(ops, &pernet_list, list)
+		ops_pre_exit_list(ops, &net_exit_list);
+
 	/*
 	 * Another CPU might be rcu-iterating the list, wait for it.
 	 * This needs to be before calling the exit() notifiers, so
 	 * the rcu_barrier() below isn't sufficient alone.
+	 * Also the pre_exit() and exit() methods need this barrier.
 	 */
 	synchronize_rcu();
 
@@ -722,7 +745,7 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
 	err = alloc_netid(net, peer, nsid);
 	spin_unlock_bh(&net->nsid_lock);
 	if (err >= 0) {
-		rtnl_net_notifyid(net, RTM_NEWNSID, err);
+		rtnl_net_notifyid(net, RTM_NEWNSID, err, GFP_KERNEL);
 		err = 0;
 	} else if (err == -ENOSPC && nsid >= 0) {
 		err = -EEXIST;
@@ -1009,7 +1032,7 @@ end:
 	return err < 0 ? err : skb->len;
 }
 
-static void rtnl_net_notifyid(struct net *net, int cmd, int id)
+static void rtnl_net_notifyid(struct net *net, int cmd, int id, gfp_t gfp)
 {
 	struct net_fill_args fillargs = {
 		.cmd = cmd,
@@ -1018,7 +1041,7 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id)
 	struct sk_buff *msg;
 	int err = -ENOMEM;
 
-	msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
+	msg = nlmsg_new(rtnl_net_get_size(), gfp);
 	if (!msg)
 		goto out;
 
@@ -1026,7 +1049,7 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id)
 	if (err < 0)
 		goto err_out;
 
-	rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0);
+	rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, gfp);
 	return;
 
 err_out:
@@ -1101,6 +1124,8 @@ static int __register_pernet_operations(struct list_head *list,
 out_undo:
 	/* If I have an error cleanup all namespaces I initialized */
 	list_del(&ops->list);
+	ops_pre_exit_list(ops, &net_exit_list);
+	synchronize_rcu();
 	ops_exit_list(ops, &net_exit_list);
 	ops_free_list(ops, &net_exit_list);
 	return error;
@@ -1115,6 +1140,8 @@ static void __unregister_pernet_operations(struct pernet_operations *ops)
 	/* See comment in __register_pernet_operations() */
 	for_each_net(net)
 		list_add_tail(&net->exit_list, &net_exit_list);
+	ops_pre_exit_list(ops, &net_exit_list);
+	synchronize_rcu();
 	ops_exit_list(ops, &net_exit_list);
 	ops_free_list(ops, &net_exit_list);
 }
@@ -1139,6 +1166,8 @@ static void __unregister_pernet_operations(struct pernet_operations *ops)
 	} else {
 		LIST_HEAD(net_exit_list);
 		list_add(&init_net.exit_list, &net_exit_list);
+		ops_pre_exit_list(ops, &net_exit_list);
+		synchronize_rcu();
 		ops_exit_list(ops, &net_exit_list);
 		ops_free_list(ops, &net_exit_list);
 	}