netdev - [PATCH 07/12] can: cc770: don't touch skb after netif

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Message-Id: <1436944189-26618-8-git-send-email-mkl@pengutronix.de>
Date:	Wed, 15 Jul 2015 09:09:44 +0200
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, linux-can@...r.kernel.org,
	kernel@...gutronix.de, Marc Kleine-Budde <mkl@...gutronix.de>,
	Wolfgang Grandegger <wg@...ndegger.com>
Subject: [PATCH 07/12] can: cc770: don't touch skb after netif_rx()

There is no guarantee that the skb is in the same state after calling
net_receive_skb() or netif_rx(). It might be freed or reused. Not really
harmful as its a read access, except you turn on the proper debugging options
which catch a use after free.

Cc: Wolfgang Grandegger <wg@...ndegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/cc770/cc770.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c
index c11d44984036..70a8cbb29e75 100644
--- a/drivers/net/can/cc770/cc770.c
+++ b/drivers/net/can/cc770/cc770.c
@@ -504,10 +504,10 @@ static void cc770_rx(struct net_device *dev, unsigned int mo, u8 ctrl1)
 		for (i = 0; i < cf->can_dlc; i++)
 			cf->data[i] = cc770_read_reg(priv, msgobj[mo].data[i]);
 	}
-	netif_rx(skb);
 
 	stats->rx_packets++;
 	stats->rx_bytes += cf->can_dlc;
+	netif_rx(skb);
 }
 
 static int cc770_err(struct net_device *dev, u8 status)
@@ -584,10 +584,10 @@ static int cc770_err(struct net_device *dev, u8 status)
 		}
 	}
 
-	netif_rx(skb);
 
 	stats->rx_packets++;
 	stats->rx_bytes += cf->can_dlc;
+	netif_rx(skb);
 
 	return 0;
 }
-- 
2.1.4

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