From: Eric Dumazet <edumazet@google.com>
Date: Wed, 25 Nov 2015 17:02:10 +0000 (-0800)
Subject: drivers: net: xgene: fix possible use after free
X-Git-Tag: v4.9.8~3093^2~31
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9ffad80a9c65d7c2ab5ad6cb8b4b0559b9ed8b8c;p=platform%2Fkernel%2Flinux-rpi3.git

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
--- 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;
 }