Re: [PATCH 8/9] check: run tests in a systemd scope for mandatory test cleanup

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Oct 27, 2020 at 12:02:21PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> If systemd is available, run each test in its own temporary systemd
> scope.  This enables the test harness to forcibly clean up all of the
> test's child processes (if it does not do so itself) so that we can move
> into the post-test unmount and check cleanly.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  check |   21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> 
> diff --git a/check b/check
> index 5072dd82..47c72fa2 100755
> --- a/check
> +++ b/check
> @@ -521,6 +521,11 @@ _expunge_test()
>  	return 0
>  }
>  
> +# Can we run systemd scopes?
> +HAVE_SYSTEMD_SCOPES=
> +systemd-run --quiet --unit "fstests-check" --scope bash -c "exit 77" &> /dev/null
> +test $? -eq 77 && HAVE_SYSTEMD_SCOPES=yes
> +
>  # Make the check script unattractive to the OOM killer...
>  OOM_SCORE_ADJ="/proc/self/oom_score_adj"
>  test -w ${OOM_SCORE_ADJ} && echo -1000 > ${OOM_SCORE_ADJ}
> @@ -528,8 +533,22 @@ test -w ${OOM_SCORE_ADJ} && echo -1000 > ${OOM_SCORE_ADJ}
>  # ...and make the tests themselves somewhat more attractive to it, so that if
>  # the system runs out of memory it'll be the test that gets killed and not the
>  # test framework.
> +#
> +# If systemd is available, run the entire test script in a scope so that we can
> +# kill all subprocesses of the test if it fails to clean up after itself.  This
> +# is essential for ensuring that the post-test unmount succeeds.
>  _run_seq() {
> -	bash -c "test -w ${OOM_SCORE_ADJ} && echo 250 > ${OOM_SCORE_ADJ}; exec ./$seq"
> +	local cmd=(bash -c "test -w ${OOM_SCORE_ADJ} && echo 250 > ${OOM_SCORE_ADJ}; exec ./$seq")
> +
> +	if [ -n "${HAVE_SYSTEMD_SCOPES}" ]; then
> +		local unit="$(systemd-escape "fs$seq").scope"
> +		systemd-run --quiet --unit "${unit}" --scope "${cmd[@]}"

/me discovers that systemd preserves failed transient scopes (where
"failed" means the processes get killed, not that they return nonzero),
so this patch has to reset-failed the scope in case the user calls
fstests before rebooting.

Hence, self NAK.

--D

> +		res=$?
> +		systemctl stop "${unit}" &> /dev/null
> +		return "${res}"
> +	else
> +		"${cmd[@]}"
> +	fi
>  }
>  
>  _detect_kmemleak
>