1 files changed, 21 insertions, 15 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 3b13d9e4030a..3086211829a7 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -630,7 +630,8 @@ static void tun_detach_all(struct net_device *dev)
 		module_put(THIS_MODULE);
 }
 
-static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
+static int tun_attach(struct tun_struct *tun, struct file *file,
+		      bool skip_filter, bool publish_tun)
 {
 	struct tun_file *tfile = file->private_data;
 	struct net_device *dev = tun->dev;
@@ -672,7 +673,8 @@ static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filte
 
 	tfile->queue_index = tun->numqueues;
 	tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
-	rcu_assign_pointer(tfile->tun, tun);
+	if (publish_tun)
+		rcu_assign_pointer(tfile->tun, tun);
 	rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
 	tun->numqueues++;
 
@@ -831,18 +833,8 @@ static void tun_net_uninit(struct net_device *dev)
 /* Net device open. */
 static int tun_net_open(struct net_device *dev)
 {
-	struct tun_struct *tun = netdev_priv(dev);
-	int i;
-
 	netif_tx_start_all_queues(dev);
 
-	for (i = 0; i < tun->numqueues; i++) {
-		struct tun_file *tfile;
-
-		tfile = rtnl_dereference(tun->tfiles[i]);
-		tfile->socket.sk->sk_write_space(tfile->socket.sk);
-	}
-
 	return 0;
 }
 
@@ -1360,6 +1352,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
 
 	skb_reserve(skb, pad - delta);
 	skb_put(skb, len + delta);
+	skb_set_owner_w(skb, tfile->socket.sk);
 	get_page(alloc_frag->page);
 	alloc_frag->offset += buflen;
 
@@ -2020,7 +2013,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		if (err < 0)
 			return err;
 
-		err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
+		err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER, true);
 		if (err < 0)
 			return err;
 
@@ -2109,13 +2102,17 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 				       NETIF_F_HW_VLAN_STAG_TX);
 
 		INIT_LIST_HEAD(&tun->disabled);
-		err = tun_attach(tun, file, false);
+		err = tun_attach(tun, file, false, false);
 		if (err < 0)
 			goto err_free_flow;
 
 		err = register_netdevice(tun->dev);
 		if (err < 0)
 			goto err_detach;
+		/* free_netdev() won't check refcnt, to aovid race
+		 * with dev_put() we need publish tun after registration.
+		 */
+		rcu_assign_pointer(tfile->tun, tun);
 	}
 
 	netif_carrier_on(tun->dev);
@@ -2261,7 +2258,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr)
 		ret = security_tun_dev_attach_queue(tun->security);
 		if (ret < 0)
 			goto unlock;
-		ret = tun_attach(tun, file, false);
+		ret = tun_attach(tun, file, false, true);
 	} else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
 		tun = rtnl_dereference(tfile->tun);
 		if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
@@ -2826,6 +2823,7 @@ static int tun_device_event(struct notifier_block *unused,
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct tun_struct *tun = netdev_priv(dev);
+	int i;
 
 	if (dev->rtnl_link_ops != &tun_link_ops)
 		return NOTIFY_DONE;
@@ -2835,6 +2833,14 @@ static int tun_device_event(struct notifier_block *unused,
 		if (tun_queue_resize(tun))
 			return NOTIFY_BAD;
 		break;
+	case NETDEV_UP:
+		for (i = 0; i < tun->numqueues; i++) {
+			struct tun_file *tfile;
+
+			tfile = rtnl_dereference(tun->tfiles[i]);
+			tfile->socket.sk->sk_write_space(tfile->socket.sk);
+		}
+		break;
 	default:
 		break;
 	}