drivers: net: xgene: fix possible use after free

Once TX has been enabled on a NIC, it is illegal to access skb,
as this skb might have been freed by another cpu, from TX completion
handler.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: Iyappan Subramanian <isubramanian@apm.com>
Acked-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index 1adfe70..9147a01 100644 (file)
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -450,12 +450,12 @@ static netdev_tx_t xgene_enet_start_xmit(struct sk_buff *skb,
                return NETDEV_TX_OK;
        }
 
-       pdata->ring_ops->wr_cmd(tx_ring, count);
        skb_tx_timestamp(skb);
 
        pdata->stats.tx_packets++;
        pdata->stats.tx_bytes += skb->len;
 
+       pdata->ring_ops->wr_cmd(tx_ring, count);
        return NETDEV_TX_OK;
 }