It seems like bpo-45200: "Address Sanitizer: libasan dead lock in pthread_create() (test_multiprocessing_fork.test_get() hangs)" is not fixed yet.

In the GitHub Action job, test_multiprocessing_fork is skipped because it's too slow, so the job doesn't hang.

Yesterday, I modified the ASAN buildbot to double its timeout from 20 to 40 minutes:
https://github.com/python/buildmaster-config/commit/5a37411e75c9475d48eabaac18102a3c9fc2d467

But it's useful, when it hangs, it hangs forever. Exmaple on the AMD64 Arch Linux Asan Debug 3.9 buildbot (with the new config):

---
(test.test_multiprocessing_fork.WithProcessesTestPicklingConnections) ... ok
Timeout (0:35:00)!
---
https://buildbot.python.org/all/#/builders/588/builds/332

Tests are tuned for ASAN, but the configuration is copied and inconsistent between the GitHub Actions job and the buildbot configuration.

I propose to move this configuration directly into Python.

test_decimal.py checks for "-fsanitize=address" in CFLAGS and skip some tests if it's present.