From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Sat, 11 Jul 2015 19:16:08 +0000 (+0200)
Subject: can: grcan: don't touch skb after netif_rx()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=83537b6fd6c3752bcb578d2bd46312d1e2c4a73a;p=linux-beck.git

can: grcan: 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: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---

diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index e3d7e22a4fa0..db9538d4b358 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -1216,11 +1216,12 @@ static int grcan_receive(struct net_device *dev, int budget)
 				cf->data[i] = (u8)(slot[j] >> shift);
 			}
 		}
-		netif_receive_skb(skb);
 
 		/* Update statistics and read pointer */
 		stats->rx_packets++;
 		stats->rx_bytes += cf->can_dlc;
+		netif_receive_skb(skb);
+
 		rd = grcan_ring_add(rd, GRCAN_MSG_SIZE, dma->rx.size);
 	}