ERROR: Command errored out with exit status -11

Question

I ran this command in a virtual environment with Python 3.6.7 (OS: Ubuntu 21.04):

pip3 install -r requirements.txt --use-deprecated=legacy-resolver

Then I got this error:

ERROR: Command errored out with exit status -11: command: /home/username/venv/bin/python /home/username/venv/lib/python3.6/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-dm6prya6/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'poetry-core>=1.0.0' cwd: None

Complete output (0 lines):

ERROR: Command errored out with exit status -11: /home/username/venv/bin/python /home/username/venv/lib/python3.6/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-dm6prya6/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'poetry-core>=1.0.0' Check the logs for full command output.