net: hisilicon: Fix potential use-after-free in hix5hd2_rx()

The skb is delivered to napi_gro_receive() which may free it, after
calling this, dereferencing skb may trigger use-after-free.

Fixes: 57c5bc9 ("net: hisilicon: add hix5hd2 mac driver")
Signed-off-by: Liu Jian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: liujian56

drivers/net/ethernet/hisilicon/hix5hd2_gmac.c

@@ -550,7 +550,7 @@ static int hix5hd2_rx(struct net_device *dev, int limit)
 		skb->protocol = eth_type_trans(skb, dev);
 		napi_gro_receive(&priv->napi, skb);
 		dev->stats.rx_packets++;
-		dev->stats.rx_bytes += skb->len;
+		dev->stats.rx_bytes += len;
 next:
 		pos = dma_ring_incr(pos, RX_DESC_NUM);
 	}