static void put_ucounts(struct ucounts *ucounts)
{
	unsigned long flags;

	spin_lock_irqsave(&ucounts_lock, flags);
	ucounts->count -= 1;
	if (!ucounts->count)
		hlist_del_init(&ucounts->node);
	else
		ucounts = NULL;
	spin_unlock_irqrestore(&ucounts_lock, flags);

	kfree(ucounts);
}
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.