[Xen-devel] [PATCH] xen/netfront: tolerate frags with no data

[Juergen Gross <jgross@xxxxxxxx>]

At least old Xen net backends seem to send frags with no real data
sometimes. In case such a fragment happens to occur with the frag limit
already reached the frontend will BUG currently even if this situation
is easily recoverable.

Modify the BUG_ON() condition accordingly.

Cc: stable@xxxxxxxxxxxxxxx
Tested-by: Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 drivers/net/xen-netfront.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index f17f602e6171..5b97cc946d70 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -905,7 +905,7 @@ static RING_IDX xennet_fill_frags(struct netfront_queue 
*queue,
                if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
                        unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 
-                       BUG_ON(pull_to <= skb_headlen(skb));
+                       BUG_ON(pull_to < skb_headlen(skb));
                        __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
                }
                if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
-- 
2.16.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel