From: Thomas Gleixner Date: Fri, 11 Apr 2014 08:13:12 +0000 (+0000) Subject: can: c_can: Do not access skb after net_receive_skb() X-Git-Tag: v3.15-rc5~17^2~39^2~22 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=9c64863a49bd23c5a3a983680eb500f7796c81be;p=~emulex%2Finfiniband.git can: c_can: Do not access skb after net_receive_skb() There is no guarantee that the skb is in the same state after calling net_receive_skb(). 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. The whole can subsystem is full of this. Copy and paste .... Signed-off-by: Thomas Gleixner Tested-by: Alexander Stein Signed-off-by: Marc Kleine-Budde --- diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 8c725f40bc1..603876109ba 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -429,10 +429,10 @@ static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl) } } - netif_receive_skb(skb); - stats->rx_packets++; stats->rx_bytes += frame->can_dlc; + + netif_receive_skb(skb); return 0; } @@ -960,9 +960,9 @@ static int c_can_handle_state_change(struct net_device *dev, break; } - netif_receive_skb(skb); stats->rx_packets++; stats->rx_bytes += cf->can_dlc; + netif_receive_skb(skb); return 1; } @@ -1033,10 +1033,9 @@ static int c_can_handle_bus_err(struct net_device *dev, /* set a `lec` value so that we can check for updates later */ priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED); - netif_receive_skb(skb); stats->rx_packets++; stats->rx_bytes += cf->can_dlc; - + netif_receive_skb(skb); return 1; }