Re: [PATCH 2/2] ftrace/selftest: Test if set_event/ftrace_pid exists before writing

[Masami Hiramatsu]

On Wed, 3 Jul 2019 16:00:09 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Wed, 03 Jul 2019 15:50:01 -0400
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> 
> > From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
> > 
> > While testing on a very old kernel (3.5), the tests failed because the write
> > to set_event_pid in the setup code, did not exist. The tests themselves
> > could pass, but the setup failed causing an error.
> > 
> > Other files test for existance before writing to them. Do the same for
> > set_event_pid and set_ftrace_pid.
> > 
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> > ---
> >  tools/testing/selftests/ftrace/test.d/functions | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> > index 779ec11f61bd..a7b06291e32c 100644
> > --- a/tools/testing/selftests/ftrace/test.d/functions
> > +++ b/tools/testing/selftests/ftrace/test.d/functions
> > @@ -91,8 +91,8 @@ initialize_ftrace() { # Reset ftrace to initial-state
> >      reset_events_filter
> >      reset_ftrace_filter
> >      disable_events
> > -    echo > set_event_pid	# event tracer is always on
> > -    echo > set_ftrace_pid
> > +    [ -f set_event_pid ] && echo > set_event_pid  # event tracer is always on
> 
> I probably should remove that comment, because I believe that was why
> it wasn't tested :-/

Hmm, OK. I think this comment means "the event tracer is always on if clearing
set_event_pid filter". Would this need to be removed?

Thank you,

> 
> -- Steve
> 
> 
> > +    [ -f set_ftrace_pid ] && echo > set_ftrace_pid
> >      [ -f set_ftrace_filter ] && echo | tee set_ftrace_*
> >      [ -f set_graph_function ] && echo | tee set_graph_*
> >      [ -f stack_trace_filter ] && echo > stack_trace_filter
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>