1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index f09948b009dd..1d9940d4e8c7 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -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);