CUDA - Creating objects in kernel and using them at host [duplicate]

I need to use polymorphism in my kernels. The only way of doing this is to create those objects on the device (to make a virtual mehod table available at the device). Here's the object being created

class Production {
    Vertex * boundVertex;
}


class Vertex {
    Vertex * leftChild;
    Vertex * rightChild;
}

Then on the host I do:

Production* dProd;
cudaMalloc(&dProd, sizeof(Production *));
createProduction<<<1,1>>>(dProd);

where

__global__ void createProduction(Production * prod) {
    prod = new Production();
    prod->leftChild = new Vertex();
    prod->rightChild = new Vertex();
}

The question is how do I get both left and right vertices of the production created on the device back on the host? I know using pointers in classes makes them very hard to handle but... no other way of creating such tree structure.