xen/netfront: tolerate frags with no data

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. Tested-by: Dietmar Hahn <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: David S. Miller <[email protected]>
btm · Dec 19, 2018 · d81c505 · d81c505
1 parent 8742beb
commit d81c505
Showing 1 changed file with 1 addition and 1 deletion.
diff --git 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)) {