From ffc7c7cb9b2117b23e27877af59003c6fb513b88 Mon Sep 17 00:00:00 2001 From: Seth Forshee <seth.forshee@canonical.com> Date: Tue, 25 Nov 2014 20:28:24 -0600 Subject: [PATCH] xen-netfront: Remove BUGs on paged skb data which crosses a page boundary 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: c08d206e4297 ("xen/netfront: handle compound page fragments on transmit") Cc: <stable@vger.kernel.org> # 3.7+ Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- drivers/net/xen-netfront.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index cca871346a0ff..ece8d1804d136 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -496,9 +496,6 @@ static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue *queue, len = skb_frag_size(frag); offset = frag->page_offset; - /* Data must not cross a page boundary. */ - BUG_ON(len + offset > PAGE_SIZE<<compound_order(page)); - /* Skip unused frames from start of page */ page += offset >> PAGE_SHIFT; offset &= ~PAGE_MASK; @@ -506,8 +503,6 @@ static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue *queue, while (len > 0) { unsigned long bytes; - BUG_ON(offset >= PAGE_SIZE); - bytes = PAGE_SIZE - offset; if (bytes > len) bytes = len; -- 2.39.5