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FAILED: patch "[PATCH] can: usb_8dev: usb_8dev_start_xmit(): fix double" failed to apply to 4.19-stable tree

PATCH [email protected] 1 participant 1 message Apr 1, 2022

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Stable branch CAN network drivers
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The patch below does not apply to the 4.19-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 <[email protected]>.

thanks,

greg k-h

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

From 3d3925ff6433f98992685a9679613a2cc97f3ce2 Mon Sep 17 00:00:00 2001
From: Hangyu Hua <[email protected]>
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/[email protected] open here
Cc [email protected]
Signed-off-by Hangyu Hua <[email protected]>
Signed-off-by Marc Kleine-Budde <[email protected]>
drivers/net/can/usb/usb_8dev.c +14 -16
index 431af1ec1e3c..b638604bf1ee 100644
@@ -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);