Share an instance between modules

Question

I have two autofac modules WorldModule and RegionModule (separte class that inherits Module) and overwrite the load function. Both must share a worldService, service that uses an world model (singleton).

This is the worldmodule class:

      builder.RegisterType<World>().AsSelf()
            .AsImplementedInterfaces()
            .SingleInstance();

        builder.RegisterType<WorldService>().AsImplementedInterfaces();

In the region i want to have the same worldservice instance. This is the region module class:

builder.RegisterBuildCallback(c =>
        {
            Task.Run(async () =>
            {
                while (true)
                {
                    var x = c.Resolve<IWorldService>() as WorldService;
                    if (x.RegionWasAssignedToRegionServers == true)
                    {
                     c.Resolve<IRegionService> ().AssignAreaMapToServer();
                        break;
                    }
                    await Task.Delay(200);
                }
            });
        });