can: kvaser_usb: kvaser_usb_read_bulk_callback(): fix URB memory leak

commit 248e8e1 upstream.

Fix similar memory leak as in commit 7352e1d ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").

In kvaser_usb_set_{,data_}bittiming() -> kvaser_usb_setup_rx_urbs(), the
URBs for USB-in transfers are allocated, added to the dev->rx_submitted
anchor and submitted. In the complete callback
kvaser_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
kvaser_usb_remove_interfaces() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).

However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in usb_kill_anchored_urbs().

Fix the memory leak by anchoring the URB in the
kvaser_usb_read_bulk_callback() to the dev->rx_submitted anchor.

Fixes: 080f40a ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260116-can_usb-fix-memory-leak-v2-3-4b8cb2915571@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: marckleinebudde

drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c

@@ -361,15 +361,22 @@ static void kvaser_usb_read_bulk_callback(struct urb *urb)
 			  urb->transfer_buffer, KVASER_USB_RX_BUFFER_SIZE,
 			  kvaser_usb_read_bulk_callback, dev);
 
+	usb_anchor_urb(urb, &dev->rx_submitted);
+
 	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (!err)
+		return;
+
+	usb_unanchor_urb(urb);
+
 	if (err == -ENODEV) {
 		for (i = 0; i < dev->nchannels; i++) {
 			if (!dev->nets[i])
 				continue;
 
 			netif_device_detach(dev->nets[i]->netdev);
 		}
-	} else if (err) {
+	} else {
 		dev_err(&dev->intf->dev,
 			"Failed resubmitting read bulk urb: %d\n", err);
 	}