Crash report

What happened?

On MacOS, calling ssl.SSLContext.load_verify_locations from multiple threads causes a SIGSEGV during process termination when an unhandled exception is raised.

I was able to create a repoduction case and I've attached the five MacOS crash reports here.

Reproduction

from multiprocessing.pool import ThreadPool
import ssl
import certifi

ctx = ssl.create_default_context()
location = certifi.where()


def test_func(_):
    ctx.load_verify_locations(location)


with ThreadPool(processes=100) as pool:
    for idx, item in enumerate(pool.imap_unordered(test_func, range(1000), chunksize=1)):
        if idx == 100:
            raise RuntimeError()

Traceback (most recent call last):
  File "/Users/tomforbes/tmp/scanner/repo.py", line 16, in <module>
    raise RuntimeError()
RuntimeError
fish: Job 1, 'python repo.py' terminated by signal SIGSEGV (Address boundary error)

MacOS crash reports:

five.txt
four.txt
one.txt
three.txt
two.txt

CPython versions tested on:

3.11

Operating systems tested on:

macOS

Output from running 'python -VV' on the command line:

Python 3.11.7 (v3.11.7:fa7a6f2303, Dec 4 2023, 15:22:56) [Clang 13.0.0 (clang-1300.0.29.30)]