Re: [PATCH] selftests/ftrace: remove _do_fork() leftovers

From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	Christian Brauner <christian.brauner@ubuntu.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH] selftests/ftrace: remove _do_fork() leftovers
Date: Sat, 24 Oct 2020 10:31:12 +0900	[thread overview]
Message-ID: <20201024103112.64372203e6729279e9ef92f5@kernel.org> (raw)
In-Reply-To: <20201023093523.65c495f8@gandalf.local.home>

On Fri, 23 Oct 2020 09:35:23 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Fri, 23 Oct 2020 10:52:03 +0200
> Alexander Gordeev <agordeev@linux.ibm.com> wrote:
> 
> > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc
> > index acb17ce..0ddb948 100644
> > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc
> > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc
> > @@ -39,7 +39,7 @@ do_test() {
> >      disable_tracing
> >  
> >      echo do_execve* > set_ftrace_filter
> > -    echo *do_fork >> set_ftrace_filter
> > +    echo kernel_clone >> set_ftrace_filter
> >  
> >      echo $PID > set_ftrace_notrace_pid
> >      echo function > current_tracer
> > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc
> > index 9f0a968..71319b3 100644
> > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc
> > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc
> > @@ -39,7 +39,7 @@ do_test() {
> >      disable_tracing
> >  
> >      echo do_execve* > set_ftrace_filter
> > -    echo *do_fork >> set_ftrace_filter
> > +    echo kernel_clone >> set_ftrace_filter
> >  
> >      echo $PID > set_ftrace_pid
> >      echo function > current_tracer
> 
> The issue I have with this, is that I run these tests on older kernels too,
> and tests that use to work on older kernels should still work. In fact,
> this fails on the kernel I'm currently adding new changes to!
> 
> Perhaps we should have:
> 
> 	# older kernels have do_fork, but newer kernels have kernel_clone
> 	echo kernel_clone >> set_ftrace_filter || echo *do_fork >> set_ftrace_filter

Good catch. BTW, can we check the filter-bility by grep the pattern from set_ftrace_filter?

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>