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[Xen-devel] [PATCH] xen: netback: Drop GSO SKBs which do not have csum_b

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Subject: [Xen-devel] [PATCH] xen: netback: Drop GSO SKBs which do not have csum_blank.
From: Ian Campbell <ian.campbell@xxxxxxxxxx>
Date: Wed, 5 Jan 2011 12:54:14 +0000
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, Ian Campbell <ian.campbell@xxxxxxxxxx>
Delivery-date: Wed, 05 Jan 2011 04:55:58 -0800
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The Linux network stack expects all GSO SKBs to have ip_summed ==
CHECKSUM_PARTIAL (which implies that the frame contains a partial
checksum) and the Xen network ring protocol similarly expects an SKB
which has GSO set to also have NETRX_csum_blank (which also implies a
partial checksum). Therefore drop such frames on receive otherwise
they will trigger the warning in skb_gso_segment.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
 drivers/xen/netback/netback.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/netback/netback.c b/drivers/xen/netback/netback.c
index 1e362f7..851721a 100644
--- a/drivers/xen/netback/netback.c
+++ b/drivers/xen/netback/netback.c
@@ -1513,6 +1513,10 @@ static void net_tx_submit(struct xen_netbk *netbk)
+               } else if (skb_is_gso(skb)) {
+                       DPRINTK("Dropping GSO but not CHECKSUM_PARTIAL skb\n");
+                       kfree_skb(skb);
+                       continue;
                if (unlikely(netbk_copy_skb_mode == NETBK_ALWAYS_COPY_SKB) &&

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