can: usb_8dev: usb_8dev_start_xmit(): fix double dev_kfree_skb() in error path

commit 3d3925ff6433f98992685a9679613a2cc97f3ce2 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
because can_put_echo_skb() deletes original skb and
can_free_echo_skb() deletes the cloned skb.

Fixes: 0024d8ad1639 ("can: usb_8dev: Add support for USB2CAN interface from 8 devices")
Link: https://lore.kernel.org/all/20220311080614.45229-1-hbh25y@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
[DP: adjusted params of can_free_echo_skb() for 4.19 stable]
Signed-off-by: Dragos-Marian Panait <dragos.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/can/usb/usb_8dev.c b/drivers/net/can/usb/usb_8dev.c
index df99354ec12aaaf36f93e926107a290d3777b263..232f45f722f0c7e405ffeef27bb0afeafd95564d 100644 (file)
--- a/drivers/net/can/usb/usb_8dev.c
+++ b/drivers/net/can/usb/usb_8dev.c
@@ -681,9 +681,20 @@ static netdev_tx_t usb_8dev_start_xmit(struct sk_buff *skb,
        atomic_inc(&priv->active_tx_urbs);
 
        err = usb_submit_urb(urb, GFP_ATOMIC);
-       if (unlikely(err))
-               goto failed;
-       else if (atomic_read(&priv->active_tx_urbs) >= MAX_TX_URBS)
+       if (unlikely(err)) {
+               can_free_echo_skb(netdev, context->echo_index);
+
+               usb_unanchor_urb(urb);
+               usb_free_coherent(priv->udev, size, buf, urb->transfer_dma);
+
+               atomic_dec(&priv->active_tx_urbs);
+
+               if (err == -ENODEV)
+                       netif_device_detach(netdev);
+               else
+                       netdev_warn(netdev, "failed tx_urb %d\n", err);
+               stats->tx_dropped++;
+       } else if (atomic_read(&priv->active_tx_urbs) >= MAX_TX_URBS)
                /* Slow down tx path */
                netif_stop_queue(netdev);
 
@@ -702,19 +713,6 @@ static netdev_tx_t usb_8dev_start_xmit(struct sk_buff *skb,
 
        return NETDEV_TX_BUSY;
 
-failed:
-       can_free_echo_skb(netdev, context->echo_index);
-
-       usb_unanchor_urb(urb);
-       usb_free_coherent(priv->udev, size, buf, urb->transfer_dma);
-
-       atomic_dec(&priv->active_tx_urbs);
-
-       if (err == -ENODEV)
-               netif_device_detach(netdev);
-       else
-               netdev_warn(netdev, "failed tx_urb %d\n", err);
-
 nomembuf:
        usb_free_urb(urb);