Pytest hangs when using faulthandler_timeout with pytest-forked

Steps to reproduce

Create two files in root workspace

# foo.py
def test_bar():
    fjaoisjdfoiajsdofi

# pyproject.toml
[tool.pytest.ini_options]
faulthandler_timeout=1800

Create a minimal venv with pytest-forked

mkvirtualenv foo --python 3.7
pip install pytest-forked==1.3.0

Run the following,

pytest foo.py --forked

pytest should hang indefinitely during collection

=========================================================================================== test session starts ============================================================================================
platform linux -- Python 3.7.5, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: /home/tyler/playground/pytest-forked-repro, configfile: pyproject.toml
plugins: forked-1.3.0
collected 1 item                                                                                                                                                                                           

foo.py 

Reproduce the issue with foo.py and pyproject.toml from the report, using Python 3.7, pytest-forked 1.3.0, and pytest foo.py --forked. Start by tracing what happens during collection when faulthandler_timeout is configured. Done means the command completes collection and no longer hangs indefinitely.