can: flexcan: don't touch skb after netif_receive_skb()

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.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 6201c5a1a8845f2e3e68f3921a2fcae8e4469217..b1e8d729851cbb5173c1bbec2b34c4893b2ff595 100644 (file)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -577,10 +577,10 @@ static int flexcan_poll_bus_err(struct net_device *dev, u32 reg_esr)
                return 0;
 
        do_bus_err(dev, cf, reg_esr);
-       netif_receive_skb(skb);
 
        dev->stats.rx_packets++;
        dev->stats.rx_bytes += cf->can_dlc;
+       netif_receive_skb(skb);
 
        return 1;
 }
@@ -622,10 +622,9 @@ static int flexcan_poll_state(struct net_device *dev, u32 reg_esr)
        if (unlikely(new_state == CAN_STATE_BUS_OFF))
                can_bus_off(dev);
 
-       netif_receive_skb(skb);
-
        dev->stats.rx_packets++;
        dev->stats.rx_bytes += cf->can_dlc;
+       netif_receive_skb(skb);
 
        return 1;
 }
@@ -670,10 +669,10 @@ static int flexcan_read_frame(struct net_device *dev)
        }
 
        flexcan_read_fifo(dev, cf);
-       netif_receive_skb(skb);
 
        stats->rx_packets++;
        stats->rx_bytes += cf->can_dlc;
+       netif_receive_skb(skb);
 
        can_led_event(dev, CAN_LED_EVENT_RX);