[LTP] [PATCH] tracing: ftrace_lib: check if tracing_max_latency exists.

[Sandeep Patil]

On Fri, Aug 10, 2018 at 02:57:41PM +0200, Cyril Hrubis wrote:
> Hi!
> > This avoids unnecessary error in ftrace stress test when the
> > kernel being tested does not have CONFIG_TRACER_MAX_TRACE defined.
> > 
> > Signed-off-by: Sandeep Patil <sspatil@google.com>
> > ---
> >  testcases/kernel/tracing/ftrace_test/ftrace_lib.sh | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/testcases/kernel/tracing/ftrace_test/ftrace_lib.sh b/testcases/kernel/tracing/ftrace_test/ftrace_lib.sh
> > index 20cf5e760..ec4f7a557 100755
> > --- a/testcases/kernel/tracing/ftrace_test/ftrace_lib.sh
> > +++ b/testcases/kernel/tracing/ftrace_test/ftrace_lib.sh
> > @@ -100,7 +100,9 @@ restore_old_setting()
> >  
> >  	echo nop > current_tracer
> >  	echo 0 > events/enable
> > -	echo 0 > tracing_max_latency 2> /dev/null
> > +	if [ -e tracing_max_latency ]; then
> > +		echo 0 > tracing_max_latency 2> /dev/null
> > +	fi
> 
> I guess that we can remove the 2> /dev/null that I suppose was supposed
> to silence the error. Does it work okay for you without the redirection?

Yes, just tested it. Works for me. Want me to send the patch removing it?

- ssp
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz