Fakemachine in debos immediately powers off and hangs in v2021 and v2022dev1 when using UML on the runners

Affected images versions

• not relevant: mainly affects docker test images which weren't published officially since the test stage failed
  • registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2021-image-builder@sha256:9c132379b575b75993aa7dab68585ad00de8fb00054383d6703aae4791552ed3
  • registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2022dev1-image-builder@sha256:23eaeb0822453a147d2b379cb2a8c5fd16221e9a94805e7b652ba757f3877e08

Unaffected images versions

• v2019: does not use the debos uml backend
• v2020: does not use the debos uml backend
• v2021:
  • registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2021-image-builder with digest registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2021-image-builder@sha256:cc0ddd3386256035455eaf75e4e6b45e1b31fbc5a1e685ca296c92b3f59e5177
• v2022:
  • registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2022dev1-image-builder@sha256:441096ecd6f7e268429d9f76bbef821faf076e7d8cf12947ba543aee0f0dfb2f (current latest)

Steps to reproduce

• https://gitlab.apertis.org/infrastructure/apertis-docker-images/-/jobs/644073
• https://gitlab.apertis.org/infrastructure/apertis-docker-images/-/jobs/645562
• https://gitlab.apertis.org/em/gitlab-ci-tests/-/pipelines/188342

Interestingly, I can't reproduce the issue locally with Podman containers.

Expected result

• the build should suceed

Actual result

$ debos -t osname:${DISTRO} -t suite:${RELEASE} -t mirror:"${MIRROR}" -t required_backend:uml image-builder/test-recipe.yaml
Running /debos --artifactdir /builds/infrastructure/apertis-docker-images --template-var required_backend:"uml" --template-var osname:"apertis" --template-var suite:"v2022dev1" --template-var mirror:"https://repositories.apertis.org/apertis/" /builds/infrastructure/apertis-docker-images/image-builder/test-recipe.yaml using uml backend
Powering off.
ERROR: Job failed: execution took longer than 1h0m0s seconds

Impact of bug

Highest, blocking development on apertis-docker-images

Root cause

$ docker run registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2021-image-builder dpkg -l > dpkg-v2021-latest.list
$ docker run registry.gitlab.apertis.org/infrastructure/apertis-docker-images/v2021-image-builder@sha256:9c132379b575b75993aa7dab68585ad00de8fb00054383d6703aae4791552ed3 dpkg -l > dpkg-v2021-9c132379b575b75993aa7dab68585ad00de8fb00054383d6703aae4791552ed3.list
$ diff dpkg-v2021-latest.list dpkg-v2021-9c132379b575b75993aa7dab68585ad00de8fb00054383d6703aae4791552ed3.list
402c402
< ii  user-mode-linux                  5.9um1bv2021preb2                          amd64        User-mode Linux (kernel)
---
> ii  user-mode-linux                  5.10um1co1bv2021.0b2                       amd64        User-mode Linux (kernel)

Outcomes

• pkg/user-mode-linux!8 (merged)
• pkg/user-mode-linux!9 (merged)

Management data

This section is for management only, it should be the last one in the description.

Phabricator link: https://phabricator.apertis.org/T7721