Re: [PATCH] rtla: add tests for tracefs instance cleanup

[Chaosheng Qu <chaosheng.qu.linux@gmail.com>]

Thanks, the four points split into test-harness bugs and one test premise
that I over-claimed. The series is fixed locally; details below.

1. SKIP was swallowed

cleanup.t now emits a TAP "# SKIP" line when the helper logs SKIP, instead
of reporting a plain "ok". The helper also treats a missing tracefs, a
non-writable tracefs, or a missing CONFIG_OSNOISE_TRACER as SKIP rather
than a failure.

2. SIGINT race and leaked process

The repeated-interrupt case now waits for the tracefs instance to appear
before sending SIGINT, and verifies that it disappears after each run. The
SIGINT case also reaps the background rtla when the instance never
appeared. The helper is run under the suite timeout, so a stuck wait cannot
hang forever.

I also added SIGTERM to set_signals()/unset_signals() in common.c. Before
this, rtla only handled SIGINT and SIGALRM, so SIGTERM left the instance
behind. The test now checks that path instead of recording it as a known
issue.

3. Missing exit-code checks / action case

The self-timeout case now requires exit 0, and the action case requires exit
2 (the mismatched-action result). The action case uses -S, the stop-total
threshold, and skips if that threshold was not crossed. An idle machine may
not generate a sample above 1 us; that is a property of the workload, not a
cleanup result.

4. Unused TIMEOUT / reset_osnoise / dead code

run_cleanup_cases() now calls reset_osnoise and uses $TIMEOUT. The unused
check_instances_absent() helper is gone.

The series is based on 2f2f7eeef8b0a1a9b9ca998231419873ccae8d4e and is
commit 455d304ece2a938d0148a908c83f1774d4dbf298. I ran bash -n and
checkpatch.pl locally. The host has no writable tracefs, so the suite
reports SKIP here rather than a real pass.

The patch is attached.

Thanks,
Chaosheng