int snd_timer_close(struct snd_timer_instance *timeri)
{
	struct snd_timer *timer = NULL;
	struct snd_timer_instance *slave, *tmp;

	if (snd_BUG_ON(!timeri))
		return -ENXIO;

	/* force to stop the timer */
	snd_timer_stop(timeri);

	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
		/* wait, until the active callback is finished */
		spin_lock_irq(&slave_active_lock);
		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
			spin_unlock_irq(&slave_active_lock);
			udelay(10);
			spin_lock_irq(&slave_active_lock);
		}
		spin_unlock_irq(&slave_active_lock);
		mutex_lock(&register_mutex);
		list_del(&timeri->open_list);
		mutex_unlock(&register_mutex);
	} else {
		timer = timeri->timer;
		if (snd_BUG_ON(!timer))
			goto out;
		/* wait, until the active callback is finished */
		spin_lock_irq(&timer->lock);
		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
			spin_unlock_irq(&timer->lock);
			udelay(10);
			spin_lock_irq(&timer->lock);
		}
		spin_unlock_irq(&timer->lock);
		mutex_lock(&register_mutex);
		list_del(&timeri->open_list);
		if (timer && list_empty(&timer->open_list_head) &&
 		    timer->hw.close)
 			timer->hw.close(timer);
 		/* remove slave links */
 		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
 					 open_list) {
			spin_lock_irq(&slave_active_lock);
			_snd_timer_stop(slave, 1, SNDRV_TIMER_EVENT_RESOLUTION);
 			list_move_tail(&slave->open_list, &snd_timer_slave_list);
 			slave->master = NULL;
 			slave->timer = NULL;
			spin_unlock_irq(&slave_active_lock);
 		}
 		mutex_unlock(&register_mutex);
 	}
  out:
	if (timeri->private_free)
		timeri->private_free(timeri);
	kfree(timeri->owner);
	kfree(timeri);
	if (timer)
		module_put(timer->module);
	return 0;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.