python3 multiprocessing queue deadlock when use thread and process at same time

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-12-29.02:53:42.097>
labels = ['type-bug', 'library']
title = 'python3 multiprocessing queue deadlock when use thread and process at same time'
updated_at = <Date 2020-10-20.08:13:00.437>
user = 'https://bugs.python.org/beruhan'

bugs.python.org fields:

activity = <Date 2020-10-20.08:13:00.437>
actor = 'dukewrz'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-12-29.02:53:42.097>
creator = 'beruhan'
dependencies = []
files = []
hgrepos = []
issue_num = 35608
keywords = []
message_count = 8.0
messages = ['332691', '332694', '332695', '332706', '332710', '332723', '332850', '379101']
nosy_count = 6.0
nosy_names = ['tim.peters', 'pitrou', 'davin', 'eamanu', 'beruhan', 'dukewrz']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue35608'
versions = ['Python 3.6']