Spurious warning emitted during fork() can deadlock a multi-threaded process

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-04-29.20:46:13.936>
labels = ['3.7', 'type-bug', 'library']
title = 'Spurious warning emitted during fork() can deadlock a multi-threaded process'
updated_at = <Date 2020-04-30.17:30:13.696>
user = 'https://github.com/rojer'

bugs.python.org fields:

activity = <Date 2020-04-30.17:30:13.696>
actor = 'bowiechen'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-04-29.20:46:13.936>
creator = 'rojer'
dependencies = []
files = []
hgrepos = []
issue_num = 40442
keywords = []
message_count = 1.0
messages = ['367701']
nosy_count = 4.0
nosy_names = ['vstinner', 'ionelmc', 'bowiechen', 'rojer']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40442'
versions = ['Python 3.7']