Problem when adding and removing item from a stack with linked lists in C

I have a problem adding and removing items from a stack with linked lists. My push function adds but when I want to pop them out with pop it tells me it's empty. Here is the code:

BOOLEAN lpila_push(LPila p, void* valor){
    /*Agregue su codigo de implementacion aqui*/
    LPila nuevo, tmp;
    CONFIRM_NOTNULL(p,ERROR);
    nuevo = (LPila)malloc(sizeof(LPila));

    if(nuevo != NULL){
        nuevo->valor = valor;
        nuevo->sig = NULL;
        /*Si la lista esta vacia agrega el elemento al inicio*/
        if(p->sig == NULL){
            p->sig = nuevo;
            printf("Primero agregado\n");
        }/*Si ya existen elementos en la lista, recorre y agrega al final*/
        else{
            tmp = p;
            while(tmp->sig != NULL){
                tmp = tmp->sig;
            }
            tmp->sig = nuevo;
            printf("Agregado\n");
        }
        return OK;
    }
    return ERROR;
}

BOOLEAN lpila_pop(LPila p, void** valor){
     /*Agregue su codigo de implementacion aqui*/
    LPila tmp;
    CONFIRM_NOTNULL(p,ERROR);
    if(p == NULL) printf("lista vacia\n");
    tmp = p;

    while(tmp != NULL){
        tmp = tmp->sig;
    }
    valor = &tmp->valor;
    free(tmp);
    return OK;
}

int main(int argc, char** argv) {
    LPila p = lpila_crear();
    char* data =(char*) malloc(sizeof(char)*10);
    if(NULL==p) printf("pila nula! \n");
    {
        char* test = (char*)malloc(sizeof(char)*10);
        char* test1 = (char*)malloc(sizeof(char)*10);

        test = "10.000";
        test1 = "15.000";
        lpila_push(p,&test);
        lpila_push(p,&test1);
    }
    lpila_pop(p,(void**)&data);
    printf("data=%s \n",data);
    printf("isempty=%d\n", lpila_isEmpty(p) );
    lpila_pop(p,(void**)&data);
    printf("isempty=%d\n", lpila_isEmpty(p) );

    system("pause");
    return (EXIT_SUCCESS);
}