evtchn_port_t evtchn_from_irq(unsigned irq)
{
	const struct irq_info *info = NULL;

	if (likely(irq < nr_irqs))
		info = info_for_irq(irq);
	if (!info)
		return 0;

	return info->evtchn;
}
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.