From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: [PATCH 02/12] can: flexcan: don't touch skb after netif_receive_skb() Date: Wed, 15 Jul 2015 09:09:39 +0200 Message-ID: <1436944189-26618-3-git-send-email-mkl@pengutronix.de> References: <1436944189-26618-1-git-send-email-mkl@pengutronix.de> Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Marc Kleine-Budde To: netdev@vger.kernel.org Return-path: In-Reply-To: <1436944189-26618-1-git-send-email-mkl@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 --- drivers/net/can/flexcan.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 6201c5a1a884..b1e8d729851c 100644 --- 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); -- 2.1.4