4 files changed, 27 insertions, 9 deletions

diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
index 0ccb021f1e78..10d580c3dea3 100644
--- a/drivers/net/xen-netback/hash.c
+++ b/drivers/net/xen-netback/hash.c
@@ -454,6 +454,8 @@ void xenvif_init_hash(struct xenvif *vif)
 	if (xenvif_hash_cache_size == 0)
 		return;
 
+	BUG_ON(vif->hash.cache.count);
+
 	spin_lock_init(&vif->hash.cache.lock);
 	INIT_LIST_HEAD(&vif->hash.cache.list);
 }
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 182d6770f102..6da12518e693 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -153,6 +153,13 @@ static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
 {
 	struct xenvif *vif = netdev_priv(dev);
 	unsigned int size = vif->hash.size;
+	unsigned int num_queues;
+
+	/* If queues are not set up internally - always return 0
+	 * as the packet going to be dropped anyway */
+	num_queues = READ_ONCE(vif->num_queues);
+	if (num_queues < 1)
+		return 0;
 
 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
 		return fallback(dev, skb, NULL) % dev->real_num_tx_queues;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 80aae3a32c2a..1d9940d4e8c7 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1072,11 +1072,6 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s
 		skb_frag_size_set(&frags[i], len);
 	}
 
-	/* Copied all the bits from the frag list -- free it. */
-	skb_frag_list_init(skb);
-	xenvif_skb_zerocopy_prepare(queue, nskb);
-	kfree_skb(nskb);
-
 	/* Release all the original (foreign) frags. */
 	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
 		skb_frag_unref(skb, f);
@@ -1145,6 +1140,8 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 		xenvif_fill_frags(queue, skb);
 
 		if (unlikely(skb_has_frag_list(skb))) {
+			struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
+			xenvif_skb_zerocopy_prepare(queue, nskb);
 			if (xenvif_handle_frag_list(queue, skb)) {
 				if (net_ratelimit())
 					netdev_err(queue->vif->dev,
@@ -1153,6 +1150,9 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 				kfree_skb(skb);
 				continue;
 			}
+			/* Copied all the bits from the frag list -- free it. */
+			skb_frag_list_init(skb);
+			kfree_skb(nskb);
 		}
 
 		skb->dev      = queue->vif->dev;
@@ -1169,15 +1169,24 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 			continue;
 		}
 
-		skb_probe_transport_header(skb, 0);
+		skb_probe_transport_header(skb);
 
 		/* If the packet is GSO then we will have just set up the
 		 * transport header offset in checksum_setup so it's now
 		 * straightforward to calculate gso_segs.
 		 */
 		if (skb_is_gso(skb)) {
-			int mss = skb_shinfo(skb)->gso_size;
-			int hdrlen = skb_transport_header(skb) -
+			int mss, hdrlen;
+
+			/* GSO implies having the L4 header. */
+			WARN_ON_ONCE(!skb_transport_header_was_set(skb));
+			if (unlikely(!skb_transport_header_was_set(skb))) {
+				kfree_skb(skb);
+				continue;
+			}
+
+			mss = skb_shinfo(skb)->gso_size;
+			hdrlen = skb_transport_header(skb) -
 				skb_mac_header(skb) +
 				tcp_hdrlen(skb);
 
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 2625740bdc4a..330ddb64930f 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -655,7 +655,7 @@ static void frontend_changed(struct xenbus_device *dev,
 		set_backend_state(be, XenbusStateClosed);
 		if (xenbus_dev_is_online(dev))
 			break;
-		/* fall through if not online */
+		/* fall through - if not online */
 	case XenbusStateUnknown:
 		set_backend_state(be, XenbusStateClosed);
 		device_unregister(&dev->dev);