linux-kernel - Re: [PATCH] perf test: Skip syscall enum test if no landlock syscall

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Message-ID: <Z5FDoxySjntN_PBP@google.com>
Date: Wed, 22 Jan 2025 11:14:43 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Howard Chu <howardchu95@...il.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Kan Liang <kan.liang@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org
Subject: Re: [PATCH] perf test: Skip syscall enum test if no landlock syscall

On Tue, Jan 21, 2025 at 04:44:49PM -0800, Howard Chu wrote:
> Hello Namhyung,
> 
> On Tue, Jan 21, 2025 at 4:17 PM Namhyung Kim <namhyung@...nel.org> wrote:
> >
> > The perf trace enum augmentation test specifically targets landlock_
> > add_rule syscall but IIUC it's an optional and can be opt-out by a
> > kernel config.
> >
> > Currently trace_landlock() runs `perf test -w landlock` before the
> > actual testing to check the availability but it's not enough since the
> > workload always returns 0.  Instead it could check if perf trace output
> > has 'landlock' string.
> 
> I remember doing the landlock syscall nr ifdef checking and returning
> -1... Somehow it's not there... Sorry.

That's ok, we can fix it later. :)

> 
> >
> > Fixes: d66763fed30f0bd8c ("perf test trace_btf_enum: Add regression test for the BTF augmentation of enums in 'perf trace'")
> > Cc: Howard Chu <howardchu95@...il.com>
> > Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> > ---
> >  tools/perf/tests/shell/trace_btf_enum.sh | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/tests/shell/trace_btf_enum.sh b/tools/perf/tests/shell/trace_btf_enum.sh
> > index 5a3b8a5a9b5cf296..e57ad6913f3e9316 100755
> > --- a/tools/perf/tests/shell/trace_btf_enum.sh
> > +++ b/tools/perf/tests/shell/trace_btf_enum.sh
> > @@ -27,7 +27,11 @@ trace_landlock() {
> >    echo "Tracing syscall ${syscall}"
> >
> >    # test flight just to see if landlock_add_rule and libbpf are available
> 
> Wonder why I put 'libbpf' here, can you please change this comment to
> '# test flight just to see if landlock_add_rule is available'
> If you find this change appropriate?

Sure, will update.

> 
> > -  $TESTPROG
> > +  if ! perf trace $TESTPROG 2>&1 | grep -q landlock
> > +  then
> > +    echo "No landlock system call found. Fallback to non-syscall tracing."
> 
> I wouldn't say it's a fallback, because the non-syscall test gets run
> even if the landlock_add_rule syscall can be invoked. Why not say: 'No
> landlock system call found, skipping to non-syscall tracing'?

Ok.

> 
> > +    return
> > +  fi
> >
> >    if perf trace -e $syscall $TESTPROG 2>&1 | \
> >       grep -q -E ".*landlock_add_rule\(ruleset_fd: 11, rule_type: (LANDLOCK_RULE_PATH_BENEATH|LANDLOCK_RULE_NET_PORT), rule_attr: 0x[a-f0-9]+, flags: 45\) = -1.*"
> > --
> > 2.48.0.rc2.279.g1de40edade-goog
> >
> 
> Other things LGTM.
> 
> Reviewed-by: Howard Chu <howardchu95@...il.com>

Thanks for your review!
Namhyung