Choosing tvm.build_config parameters

It happens during compilation .
Below is my compilation code:

with nnvm.compiler.build_config(opt_level=3):
            with tvm.build_config(auto_unroll_max_step=1440,unroll_explicit=True):
              graph, lib, params = nnvm.compiler.build(sym, target='opencl', input_dict, params=params)

and
the error log :

target device is :  opencl
compiling with optlevel =  3
Traceback (most recent call last):
  File "C:\Users\rg\Documents\Visual Studio 2015\Projects\cr\cr\src\nnvm_compile_and_exec.py", line 118, in <module>
    graph, lib, params = nnvm.compiler.build(sym, target, input_dict, params=params)
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\nnvm-0.8.0-py3.6.egg\nnvm\compiler\build_module.py", line 294, in build
    graph = graph.apply("GraphFusePartition").apply("GraphFuseCompile")
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\nnvm-0.8.0-py3.6.egg\nnvm\graph.py", line 234, in apply
    check_call(_LIB.NNGraphApplyPasses(self.handle, npass, cpass, ctypes.byref(ghandle)))
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\nnvm-0.8.0-py3.6.egg\nnvm\_base.py", line 75, in check_call
    raise NNVMError(py_str(_LIB.NNGetLastError()))
nnvm._base.NNVMError: TVMCall CFunc Error:
Traceback (most recent call last):
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\tvm-0.4.0-py3.6-win-amd64.egg\tvm\_ffi\_ctypes\function.py", line 54, in cfun
    rv = local_pyfunc(*pyargs)
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\nnvm-0.8.0-py3.6.egg\nnvm\compiler\build_module.py", line 123, in _build
    return tvm.build(funcs, target=target, target_host=target_host)
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\tvm-0.4.0-py3.6-win-amd64.egg\tvm\build_module.py", line 456, in build
    func = ir_pass.ThreadSync(func, "shared")
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\tvm-0.4.0-py3.6-win-amd64.egg\tvm\_ffi\function.py", line 280, in my_api_func
    return flocal(*args)
  File "C:\Users\rg\AppData\Roaming\Python\Python36\site-packages\tvm-0.4.0-py3.6-win-amd64.egg\tvm\_ffi\_ctypes\function.py", line 183, in __call__
    ctypes.byref(ret_val), ctypes.byref(ret_tcode)))
OSError: exception: stack overflow