static int spk_ttyio_ldisc_open(struct tty_struct *tty)
{
	struct spk_ldisc_data *ldisc_data;

	if (!tty->ops->write)
		return -EOPNOTSUPP;

	mutex_lock(&speakup_tty_mutex);
	if (speakup_tty) {
		mutex_unlock(&speakup_tty_mutex);
		return -EBUSY;
	}
	speakup_tty = tty;

	ldisc_data = kmalloc(sizeof(*ldisc_data), GFP_KERNEL);
	if (!ldisc_data) {
		speakup_tty = NULL;
		mutex_unlock(&speakup_tty_mutex);
		return -ENOMEM;
	}

	init_completion(&ldisc_data->completion);
	ldisc_data->buf_free = true;
	speakup_tty->disc_data = ldisc_data;
	mutex_unlock(&speakup_tty_mutex);

	return 0;
}
The application attempts to return a memory resource to the system, but calls the wrong release function or calls the appropriate release function incorrectly.