[PATCH 4.9 011/103] can: peak_usb: fix potential double kfree_skb()

Greg Kroah-Hartman
2019-08-22T17:45:02Z

From: Stephane Grosjean <s.grosjean@peak-system.com>

commit fee6a8923ae0d318a7f7950c6c6c28a96cea099b upstream.

When closing the CAN device while tx skbs are inflight, echo skb could
be released twice. By calling close_candev() before unlinking all
pending tx urbs, then the internal echo_skb[] array is fully and
correctly cleared before the USB write callback and, therefore,
can_get_echo_skb() are called, for each aborted URB.

Fixes: bb4785551f64 ("can: usb: PEAK-System Technik USB adapters driver core")
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/can/usb/peak_usb/pcan_usb_core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -592,16 +592,16 @@ static int peak_usb_ndo_stop(struct net_
dev->state &= ~PCAN_USB_STATE_STARTED;
netif_stop_queue(netdev);

+ close_candev(netdev);
+
+ dev->can.state = CAN_STATE_STOPPED;
+
/* unlink all pending urbs and free used memory */
peak_usb_unlink_all_urbs(dev);

if (dev->adapter->dev_stop)
dev->adapter->dev_stop(dev);

- close_candev(netdev);
-
- dev->can.state = CAN_STATE_STOPPED;
-
/* can set bus off now */
if (dev->adapter->dev_set_bus) {
int err = dev->adapter->dev_set_bus(dev, 0);