static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
				enum kvm_bus bus_idx,
				struct kvm_ioeventfd *args)
{

	struct eventfd_ctx *eventfd;
	struct _ioeventfd *p;
	int ret;

	eventfd = eventfd_ctx_fdget(args->fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	p = kzalloc(sizeof(*p), GFP_KERNEL);
	if (!p) {
		ret = -ENOMEM;
		goto fail;
	}

	INIT_LIST_HEAD(&p->list);
	p->addr    = args->addr;
	p->bus_idx = bus_idx;
	p->length  = args->len;
	p->eventfd = eventfd;

	/* The datamatch feature is optional, otherwise this is a wildcard */
	if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
		p->datamatch = args->datamatch;
	else
		p->wildcard = true;

	mutex_lock(&kvm->slots_lock);

	/* Verify that there isn't a match already */
	if (ioeventfd_check_collision(kvm, p)) {
		ret = -EEXIST;
		goto unlock_fail;
	}

	kvm_iodevice_init(&p->dev, &ioeventfd_ops);

	ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
				      &p->dev);
	if (ret < 0)
		goto unlock_fail;

	kvm_get_bus(kvm, bus_idx)->ioeventfd_count++;
	list_add_tail(&p->list, &kvm->ioeventfds);

	mutex_unlock(&kvm->slots_lock);

	return 0;

unlock_fail:
	mutex_unlock(&kvm->slots_lock);

fail:
	kfree(p);
	eventfd_ctx_put(eventfd);

	return ret;
}

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.