Comment 10 for bug 1915126

Ok, here you go. I reproduced the (or a) failure in Canonistack. This was the first run FWIW, so it wasn't too hard to get it to fail:

autopkgtest [14:05:12]: test systemd-fsckd: [-----------------------
test_fsck_failure (__main__.FsckdTest)
Ensure that a failing fsck doesn't prevent fsckd to stop ... bash: line 1: 1250 Killed /tmp/autopkgtest.5SlVJo/build.mmt/src/debian/tests/systemd-fsckd 2> >(tee -a /tmp/autopkgtest.5SlVJo/systemd-fsckd-stderr >&2) > >(tee -a /tmp/autopkgtest.5SlVJo/systemd-fsckd-stdout)
autopkgtest [14:05:16]: test process requested reboot with marker test_fsck_failure
autopkgtest-virt-ssh: WARNING: ssh connection failed. Retrying in 3 seconds...
test_fsck_failure (__main__.FsckdTest)
Ensure that a failing fsck doesn't prevent fsckd to stop ... FAIL

======================================================================
FAIL: test_fsck_failure (__main__.FsckdTest)
Ensure that a failing fsck doesn't prevent fsckd to stop
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/autopkgtest.5SlVJo/build.mmt/src/debian/tests/systemd-fsckd", line 190, in test_fsck_failure
    self.check_plymouth_start()
  File "/tmp/autopkgtest.5SlVJo/build.mmt/src/debian/tests/systemd-fsckd", line 158, in check_plymouth_start
    self.assertUnitStarted(unit)
  File "/tmp/autopkgtest.5SlVJo/build.mmt/src/debian/tests/systemd-fsckd", line 228, in assertUnitStarted
    self.assertTrue(has_unit_started(unit))
AssertionError: False is not true

----------------------------------------------------------------------
Ran 1 test in 11.289s

FAILED (failures=1)
autopkgtest [14:06:11]: test systemd-fsckd: -----------------------]
autopkgtest [14:06:12]: test systemd-fsckd: - - - - - - - - - - results - - - - - - - - - -
systemd-fsckd FAIL non-zero exit status 1
autopkgtest [14:06:13]: @@@@@@@@@@@@@@@@@@@@ summary
timedated PASS
hostnamed PASS
localed-locale PASS
localed-x11-keymap PASS
logind PASS
unit-config PASS
storage PASS
networkd-test.py PASS
build-login PASS
boot-and-services PASS
udev PASS
root-unittests PASS
tests-in-lxd PASS
upstream PASS
boot-smoke PASS
systemd-fsckd FAIL non-zero exit status 1

Full logs attached. The commandline is at the top of the log - is that enough for you to be able to have a go, Balint? I suggest adding --shell-fail of course so you can break in once it happens.