staging: usbip: vhci: refuse to enqueue for dead connections

There can be requests to enqueue URBs while we are shutting
down a connection.

Signed-off-by: Max Vozeler <[e-mail]>
Tested-by: Mark Wehby <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/usbip/vhci_hcd.c

···
 	struct device *dev = &urb->dev->dev;
 	int ret = 0;
 	unsigned long flags;
+	struct vhci_device *vdev;
 
 	usbip_dbg_vhci_hc("enter, usb_hcd %p urb %p mem_flags %d\n",
 		    hcd, urb, mem_flags);
···
 		spin_unlock_irqrestore(&the_controller->lock, flags);
 		return urb->status;
 	}
+
+	vdev = port_to_vdev(the_controller->pending_port);
+
+	/* refuse enqueue for dead connection */
+	spin_lock(&vdev->ud.lock);
+	if (vdev->ud.status == VDEV_ST_NULL || vdev->ud.status == VDEV_ST_ERROR) {
+		usbip_uerr("enqueue for inactive port %d\n", vdev->rhport);
+		spin_unlock(&vdev->ud.lock);
+		spin_unlock_irqrestore(&the_controller->lock, flags);
+		return -ENODEV;
+	}
+	spin_unlock(&vdev->ud.lock);
 
 	ret = usb_hcd_link_urb_to_ep(hcd, urb);
 	if (ret)
···
 		__u8 type = usb_pipetype(urb->pipe);
 		struct usb_ctrlrequest *ctrlreq =
 				(struct usb_ctrlrequest *) urb->setup_packet;
-		struct vhci_device *vdev =
-				port_to_vdev(the_controller->pending_port);
 
 		if (type != PIPE_CONTROL || !ctrlreq) {
 			dev_err(dev, "invalid request to devnum 0\n");