segfaulting python extension module

Makefile

crash: mytest.so
	python -c "import mytest; import numpy; mytest.foo(numpy.array([123.0]))"

mytest.so: test1.c test2.c
	$(CC) -fPIC -shared `python-config --cflags` -o $@ $^ `python-config --ldflags`

test1.c

#include "Python.h"
#include "numpy/arrayobject.h"

PyObject* foo(PyObject *self, PyObject *args);

static PyMethodDef methods[] = {
    { "foo", foo, METH_VARARGS, "" },
    { 0 }
};

PyMODINIT_FUNC initmytest()
{
    Py_InitModule("mytest", methods);
    import_array();
}

test2.c

#include "Python.h"
#include "numpy/arrayobject.h"
#include <stdio.h>

PyObject* foo(PyObject *self, PyObject *args)
{
    PyArrayObject *arr = NULL;
    if(!PyArg_ParseTuple(args, "O&", PyArray_Converter, &arr)) return NULL;
    printf("%f\n", *(double*)PyArray_DATA(arr));
    Py_DECREF(arr);
    Py_RETURN_NONE;
}