Segmentation fault in readasarray

Question

I am running the following code and get:

Segmentation fault (core dumped)

I have no clue why, I have been using the functions many times before and now suddenly this happens. Sometimes it happens at the first read of ReadAsArray, and somtimes after 20+ reads.

#!/usr/bin/python3
import numpy as np

from methods import sampler

maps = [
    '{}_slope.tif'.format(continent) for continent in ['au', 'eu']
]

def create_tiles(size):
    for ulLat in range(90, -91+size, -size):
        for ulLon in range(-180, 181-size, size):
            yield ulLon, ulLat, ulLon + size, ulLat - size

def sample_point_xy(px, py, rb, cols, rows, win_size=1, func=None):
    if (px >= 0) & (px <= cols) & (py >= 0) & (py <= rows):  # check if within map extent
        if win_size > 1:
            intval = rb.ReadAsArray(
                int(px - win_size / 2.), int(py - win_size / 2.), win_size, win_size)
        else:
            intval = rb.ReadAsArray(
                int(px), int(py), win_size, win_size)
        if func is not None:
            value = func(intval)
        else:
            value = intval
    else:
        value = np.nan
    return value

def get_samples():
    size = 4
    for m in maps:
        rb, gt, cols, rows = sampler.get_raster_info(m)
        for tile in create_tiles(size):
            ulLon, ulLat, lrLon, lrLat  = tile
            ulx, uly = sampler.MapToPixel(ulLon, ulLat, gt)
            lrx, lry = sampler.MapToPixel(lrLon, lrLat, gt)
            win_size = int(max(lrx-ulx, uly-lry))
            px, py = (ulx + lrx) / 2, (uly + lry) / 2
            sample = sample_point_xy(px, py, rb, cols, rows, win_size=win_size)
            yield sample

for sample in get_samples():
    if sample is not None and not np.isnan(sample):
        print(sample)
        print(sum(sum(sample)))