http://lists.xen.org/archives/html/xen-devel/2014-10/msg03111.html

netfront-bug-details.diff

--- a/drivers/net/xen-netfront.c	2014-10-31 15:33:16.000000000 -0400
+++ b/drivers/net/xen-netfront.c	2014-10-31 15:36:04.000000000 -0400
@@ -497,7 +497,13 @@
 		offset = frag->page_offset;

 		/* Data must not cross a page boundary. */
-		BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
+		// BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
+		if (len + offset > PAGE_SIZE<<compound_order(page)) {
+			netdev_err(queue->info->netdev, "len %d offset %d order %d PageHead %d i %d nr_frags %d \n",
+				   len, offset, compound_order(page),
+				   PageHead(page), i, skb_shinfo(skb)->nr_frags);
+			BUG();
+		}

 		/* Skip unused frames from start of page */
 		page += offset >> PAGE_SHIFT;

drivers/net/xen-netfront.c: In function ‘xennet_make_frags’:
drivers/net/xen-netfront.c:504:27: warning: passing argument 1 of ‘netdev_err’ from incompatible pointer type [enabled by default]
In file included from drivers/net/xen-netfront.c:36:0:
include/linux/netdevice.h:3535:5: note: expected ‘const struct net_device *’ but argument is of type ‘struct xenbus_device *’

Fixing by using queue->info->netdev instead of dev (previously considered queue->info->xbdev)