net: drop the packet when fails to do software segmentation or header check

Commit cecda693 ("net: keep original skb
which only needs header checking during software GSO") keeps the original
skb for packets that only needs header check, but it doesn't drop the
packet if software segmentation or header check were failed.

Fixes cecda693 ("net: keep original skb which only needs header checking during software GSO")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2673,7 +2673,7 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device
 
 		segs = skb_gso_segment(skb, features);
 		if (IS_ERR(segs)) {
-			segs = NULL;
+			goto out_kfree_skb;
 		} else if (segs) {
 			consume_skb(skb);
 			skb = segs;