void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
			       struct kvm_io_device *dev)
{
	int i;
	struct kvm_io_bus *new_bus, *bus;

	bus = kvm_get_bus(kvm, bus_idx);
	if (!bus)
		return;

	for (i = 0; i < bus->dev_count; i++)
		if (bus->range[i].dev == dev) {
			break;
		}

	if (i == bus->dev_count)
		return;

	new_bus = kmalloc(sizeof(*bus) + ((bus->dev_count - 1) *
			  sizeof(struct kvm_io_range)), GFP_KERNEL);
	if (!new_bus)  {
		pr_err("kvm: failed to shrink bus, removing it completely\n");
		goto broken;
	}

	memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
	new_bus->dev_count--;
	memcpy(new_bus->range + i, bus->range + i + 1,
	       (new_bus->dev_count - i) * sizeof(struct kvm_io_range));

broken:
	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
	synchronize_srcu_expedited(&kvm->srcu);
	kfree(bus);
	return;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.