int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
{
	int err;

	atomic_inc(&chip->usage_count);
	if (atomic_read(&chip->shutdown)) {
		err = -EIO;
		goto error;
	}
	err = snd_usb_autoresume(chip);
	if (err < 0)
		goto error;
	return 0;

 error:
	if (atomic_dec_and_test(&chip->usage_count))
		wake_up(&chip->shutdown_wait);
	return err;
}

The product reads data past the end, or before the beginning, of the intended buffer.