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SubjectRe: [PATCH] can: usb_8dev: fix possible double dev_kfree_skb in usb_8dev_start_xmit
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Gentle ping.

On 2022/3/11 16:06, Hangyu Hua wrote:
> There is no need to call dev_kfree_skb when usb_submit_urb fails beacause
> 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")
> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
> ---
> drivers/net/can/usb/usb_8dev.c | 30 ++++++++++++++----------------
> 1 file changed, 14 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/net/can/usb/usb_8dev.c b/drivers/net/can/usb/usb_8dev.c
> index 431af1ec1e3c..b638604bf1ee 100644
> --- 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(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, 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 @@ 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, 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);
>

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