usbtest_ioctl(struct usb_interface *intf, unsigned int code, void *buf)
{

	struct usbtest_dev	*dev = usb_get_intfdata(intf);
	struct usbtest_param_64 *param_64 = buf;
	struct usbtest_param_32 temp;
	struct usbtest_param_32 *param_32 = buf;
	struct timespec64 start;
	struct timespec64 end;
	struct timespec64 duration;
	int retval = -EOPNOTSUPP;

	/* FIXME USBDEVFS_CONNECTINFO doesn't say how fast the device is. */

	pattern = mod_pattern;

	if (mutex_lock_interruptible(&dev->lock))
		return -ERESTARTSYS;

	/* FIXME: What if a system sleep starts while a test is running? */

	/* some devices, like ez-usb default devices, need a non-default
	 * altsetting to have any active endpoints.  some tests change
	 * altsettings; force a default so most tests don't need to check.
	 */
	if (dev->info->alt >= 0) {
		if (intf->altsetting->desc.bInterfaceNumber) {
			retval = -ENODEV;
			goto free_mutex;
		}
		retval = set_altsetting(dev, dev->info->alt);
		if (retval) {
			dev_err(&intf->dev,
					"set altsetting to %d failed, %d\n",
					dev->info->alt, retval);
			goto free_mutex;
		}
	}

	switch (code) {
	case USBTEST_REQUEST_64:
		temp.test_num = param_64->test_num;
		temp.iterations = param_64->iterations;
		temp.length = param_64->length;
		temp.sglen = param_64->sglen;
		temp.vary = param_64->vary;
		param_32 = &temp;
		break;

	case USBTEST_REQUEST_32:
		break;

	default:
		retval = -EOPNOTSUPP;
		goto free_mutex;
	}

	ktime_get_ts64(&start);

	retval = usbtest_do_ioctl(intf, param_32);
	if (retval < 0)
		goto free_mutex;

	ktime_get_ts64(&end);

	duration = timespec64_sub(end, start);

	temp.duration_sec = duration.tv_sec;
	temp.duration_usec = duration.tv_nsec/NSEC_PER_USEC;

	switch (code) {
	case USBTEST_REQUEST_32:
		param_32->duration_sec = temp.duration_sec;
		param_32->duration_usec = temp.duration_usec;
		break;

	case USBTEST_REQUEST_64:
		param_64->duration_sec = temp.duration_sec;
		param_64->duration_usec = temp.duration_usec;
		break;
	}

free_mutex:
	mutex_unlock(&dev->lock);
	return retval;
}

The product dereferences a pointer that it expects to be valid but is NULL.