`corrupted double-linked list

[YeziLover]

Under multiprocessing (fork) mode, importing and using from cv2.xfeatures2d import matchGMS in the official OpenCV build occasionally triggers a corrupted double-linked list error. Is there a reliable fix?

[BhumikaTechHub]

From the description, this looks like a native heap corruption issue triggered when using OpenCV (specifically xfeatures2d.matchGMS) under multiprocessing with fork start method. Since this repository only handles Python wheel packaging and not the OpenCV C++ implementation itself, the root cause is likely upstream in opencv/opencv or opencv/opencv_contrib, rather than in the packaging scripts here.

As a workaround, users may want to:

Switch multiprocessing start method to spawn

import multiprocessing as mp  
mp.set_start_method("spawn", force=True)

Import cv2 inside the worker process instead of at module import time

Try limiting OpenMP threads (e.g. OMP_NUM_THREADS=1)

It might also be helpful to track this issue in the core OpenCV repository if not already done, since it appears to be related to native memory management rather than wheel building.