From: Hangyu Hua <hbh25y@xxxxxxxxx> 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@xxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/can/usb/usb_8dev.c | 30 ++++++++++++++---------------- 1 file changed, 14 insertions(+), 16 deletions(-) --- a/drivers/net/can/usb/usb_8dev.c +++ b/drivers/net/can/usb/usb_8dev.c @@ -663,9 +663,20 @@ static netdev_tx_t usb_8dev_start_xmit(s 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, NULL); + + 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); @@ -684,19 +695,6 @@ nofreecontext: return NETDEV_TX_BUSY; -failed: - can_free_echo_skb(netdev, context->echo_index, NULL); - - 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); Patches currently in stable-queue which might be from hbh25y@xxxxxxxxx are queue-5.17/can-m_can-m_can_tx_handler-fix-use-after-free-of-skb.patch queue-5.17/can-usb_8dev-usb_8dev_start_xmit-fix-double-dev_kfree_skb-in-error-path.patch queue-5.17/can-ems_usb-ems_usb_start_xmit-fix-double-dev_kfree_skb-in-error-path.patch