The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3d3925ff6433f98992685a9679613a2cc97f3ce2 Mon Sep 17 00:00:00 2001 From: Hangyu Hua hbh25y@gmail.com Date: Fri, 11 Mar 2022 16:06:14 +0800 Subject: [PATCH] can: usb_8dev: usb_8dev_start_xmit(): fix double dev_kfree_skb() in error path

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

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);