netdev - [PATCH 09/12] can: esd_usb2: don't touch skb after netif

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Message-Id: <1436944189-26618-10-git-send-email-mkl@pengutronix.de>
Date:	Wed, 15 Jul 2015 09:09:46 +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>,
	Thomas Körper <thomas.koerper@....eu>
Subject: [PATCH 09/12] can: esd_usb2: 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: Thomas Körper <thomas.koerper@....eu>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/usb/esd_usb2.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/usb/esd_usb2.c b/drivers/net/can/usb/esd_usb2.c
index 411c1af92c62..0e5a4493ba4f 100644
--- a/drivers/net/can/usb/esd_usb2.c
+++ b/drivers/net/can/usb/esd_usb2.c
@@ -301,13 +301,12 @@ static void esd_usb2_rx_event(struct esd_usb2_net_priv *priv,
 			cf->data[7] = rxerr;
 		}
 
-		netif_rx(skb);
-
 		priv->bec.txerr = txerr;
 		priv->bec.rxerr = rxerr;
 
 		stats->rx_packets++;
 		stats->rx_bytes += cf->can_dlc;
+		netif_rx(skb);
 	}
 }
 
@@ -347,10 +346,9 @@ static void esd_usb2_rx_can_msg(struct esd_usb2_net_priv *priv,
 				cf->data[i] = msg->msg.rx.data[i];
 		}
 
-		netif_rx(skb);
-
 		stats->rx_packets++;
 		stats->rx_bytes += cf->can_dlc;
+		netif_rx(skb);
 	}
 
 	return;
-- 
2.1.4

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