Re: [PATCH] net: dwc-xlgmac: set skb to NULL after freeing it

[David Miller]

From: Pan Bian <bianpan2016@xxxxxxx>
Date: Wed, 28 Nov 2018 17:20:53 +0800

> @@ -1180,6 +1180,7 @@ static int xlgmac_rx_poll(struct xlgmac_channel *channel, int budget)
>  				netif_err(pdata, rx_err, netdev,
>  					  "error in received packet\n");
>  			dev_kfree_skb(skb);
> +			skb = NULL;
>  			goto next_packet;
>  		}
>  
> @@ -1227,6 +1228,7 @@ static int xlgmac_rx_poll(struct xlgmac_channel *channel, int budget)
>  			netif_err(pdata, rx_err, netdev,
>  				  "packet length exceeds configured MTU\n");
>  			dev_kfree_skb(skb);
> +			skb = NULL;
>  			goto next_packet;
>  		}

Same problem as your amd-xgbe patch, the condition you say can occurr is
actually impossible.