proc communicate not exiting on python subprocess timeout using PIPES

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-09-13.10:11:27.791>
labels = ['type-bug', '3.8', '3.9', '3.10', 'library', 'docs']
title = 'proc communicate not exiting on python subprocess timeout using PIPES'
updated_at = <Date 2021-03-08.19:51:26.184>
user = 'https://bugs.python.org/LeonardoFrancalanci'

bugs.python.org fields:

activity = <Date 2021-03-08.19:51:26.184>
actor = 'vstinner'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation', 'Library (Lib)']
creation = <Date 2017-09-13.10:11:27.791>
creator = 'Leonardo Francalanci'
dependencies = []
files = []
hgrepos = []
issue_num = 31447
keywords = []
message_count = 17.0
messages = ['302051', '302059', '302062', '302067', '302068', '302071', '302121', '302130', '302146', '302155', '302240', '302254', '302281', '302450', '302493', '361566', '387860']
nosy_count = 9.0
nosy_names = ['paul.moore', 'tim.golden', 'r.david.murray', 'docs@python', 'martin.panter', 'zach.ware', 'eryksun', 'steve.dower', 'Leonardo Francalanci']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue31447'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']