How to allocate memory for an array of pointers within a structure

I have these structures:

struct generic_attribute{
    int current_value;
    int previous_value;
};

union union_attribute{
    struct complex_attribute *complex;
    struct generic_attribute *generic;
};

struct tagged_attribute{
    enum{GENERIC_ATTRIBUTE, COMPLEX_ATTRIBUTE} code;
    union union_attribute *attribute;
};

I keep getting segmentation fault errors because I am not allocating memory properly when creating an object of type tagged_attribute.

struct tagged_attribute* construct_tagged_attribute(int num_args, int *args){
    struct tagged_attribute *ta_ptr;
    ta_ptr = malloc (sizeof(struct tagged_attribute));
    ta_ptr->code = GENERIC_ATTRIBUTE;
    //the problem is here:
    ta_ptr->attribute->generic = malloc (sizeof(struct generic_attribute));
    ta_ptr->attribute->generic = construct_generic_attribute(args[0]);
    return  ta_ptr;
}

Construct_generic_attribute returns a pointer to a generic_attribute object. I want ta_ptr->attribute->generic to contain a pointer to a generic_attribute object. This pointer to a generic_attribute object is output by the construct_generic_attribute function.

What would be the proper way to do this?