From: Seth Forshee Date: Wed, 26 Nov 2014 02:28:24 +0000 (-0600) Subject: xen-netfront: Remove BUGs on paged skb data which crosses a page boundary X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=0a8c00c7edd66707bc60fb0dee21bdb2740baf4e;p=linux-edison.git xen-netfront: Remove BUGs on paged skb data which crosses a page boundary commit 8d609725d4357f499e2103e46011308b32f53513 upstream. These BUGs can be erroneously triggered by frags which refer to tail pages within a compound page. The data in these pages may overrun the hardware page while still being contained within the compound page, but since compound_order() evaluates to 0 for tail pages the assertion fails. The code already iterates through subsequent pages correctly in this scenario, so the BUGs are unnecessary and can be removed. Fixes: f36c374782e4 ("xen/netfront: handle compound page fragments on transmit") Signed-off-by: Seth Forshee Reviewed-by: David Vrabel Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 82e0f1fd225..a1db958df4a 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -459,9 +459,6 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev, len = skb_frag_size(frag); offset = frag->page_offset; - /* Data must not cross a page boundary. */ - BUG_ON(len + offset > PAGE_SIZE<> PAGE_SHIFT; offset &= ~PAGE_MASK; @@ -469,8 +466,6 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev, while (len > 0) { unsigned long bytes; - BUG_ON(offset >= PAGE_SIZE); - bytes = PAGE_SIZE - offset; if (bytes > len) bytes = len;