static void ib_uverbs_add_one(struct ib_device *device)
{
	int devnum;
	dev_t base;
	struct ib_uverbs_device *uverbs_dev;
	int ret;

	if (!device->ops.alloc_ucontext)
		return;

	uverbs_dev = kzalloc(sizeof(*uverbs_dev), GFP_KERNEL);
	if (!uverbs_dev)
		return;

	ret = init_srcu_struct(&uverbs_dev->disassociate_srcu);
	if (ret) {
		kfree(uverbs_dev);
		return;
	}

	device_initialize(&uverbs_dev->dev);
	uverbs_dev->dev.class = uverbs_class;
	uverbs_dev->dev.parent = device->dev.parent;
	uverbs_dev->dev.release = ib_uverbs_release_dev;
	uverbs_dev->groups[0] = &dev_attr_group;
	uverbs_dev->dev.groups = uverbs_dev->groups;
	atomic_set(&uverbs_dev->refcount, 1);
	init_completion(&uverbs_dev->comp);
	uverbs_dev->xrcd_tree = RB_ROOT;
	mutex_init(&uverbs_dev->xrcd_tree_mutex);
	mutex_init(&uverbs_dev->lists_mutex);
	INIT_LIST_HEAD(&uverbs_dev->uverbs_file_list);
	INIT_LIST_HEAD(&uverbs_dev->uverbs_events_file_list);
	rcu_assign_pointer(uverbs_dev->ib_dev, device);
	uverbs_dev->num_comp_vectors = device->num_comp_vectors;

	devnum = ida_alloc_max(&uverbs_ida, IB_UVERBS_MAX_DEVICES - 1,
			       GFP_KERNEL);
	if (devnum < 0)
		goto err;
	uverbs_dev->devnum = devnum;
	if (devnum >= IB_UVERBS_NUM_FIXED_MINOR)
		base = dynamic_uverbs_dev + devnum - IB_UVERBS_NUM_FIXED_MINOR;
	else
		base = IB_UVERBS_BASE_DEV + devnum;

	if (ib_uverbs_create_uapi(device, uverbs_dev))
		goto err_uapi;

	uverbs_dev->dev.devt = base;
	dev_set_name(&uverbs_dev->dev, "uverbs%d", uverbs_dev->devnum);

	cdev_init(&uverbs_dev->cdev,
		  device->ops.mmap ? &uverbs_mmap_fops : &uverbs_fops);
	uverbs_dev->cdev.owner = THIS_MODULE;

	ret = cdev_device_add(&uverbs_dev->cdev, &uverbs_dev->dev);
	if (ret)
		goto err_uapi;

	ib_set_client_data(device, &uverbs_client, uverbs_dev);
	return;

err_uapi:
	ida_free(&uverbs_ida, devnum);
err:
	if (atomic_dec_and_test(&uverbs_dev->refcount))
		ib_uverbs_comp_dev(uverbs_dev);
	wait_for_completion(&uverbs_dev->comp);
	put_device(&uverbs_dev->dev);
	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.