linux-kernel - Re: [PATCH v2 11/14] ftrace/selftest: Have the reset

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Date:   Wed, 16 May 2018 10:00:04 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Clark Williams <williams@...hat.com>,
        Karim Yaghmour <karim.yaghmour@...rsys.com>,
        Brendan Gregg <bgregg@...flix.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Yann Ylavic <ylavic.dev@...il.com>,
        linux-rt-users@...r.kernel.org
Subject: Re: [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code
 be a bit more careful

On Wed, 16 May 2018 21:53:50 +0900
Masami Hiramatsu <mhiramat@...nel.org> wrote:

> On Mon, 14 May 2018 16:58:56 -0400
> Steven Rostedt <rostedt@...dmis.org> wrote:
> 
> > From: "Steven Rostedt (VMware)" <rostedt@...dmis.org>
> > 
> > The trigger code is picky in how it can be disabled as there may be
> > dependencies between different events and synthetic events. Change the order
> > on how triggers are reset.
> > 
> >  1) Reset triggers of all synthetic events first
> >  2) Remove triggers with actions attached to them
> >  3) Remove all other triggers
> > 
> > If this order isn't followed, then some triggers will not be reset, and an
> > error may happen because a trigger is busy.  
> 
> Ah, right!
> 
> Acked-by: Masami Hiramatsu <mhiramat@...nel.org>

Thanks!

> 
> I think this should go into stable tree too.

I wonder if I should break this into two patches then.

One for the actions before attached, and one for synthetic events?

Hmm, maybe not. As it can handle not having synthetic events, it should
be OK to let the update go to a time when they were not there.

Thoughts?

-- Steve

> 
> Thank you!
> 
> > 
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
> > ---
> >  .../testing/selftests/ftrace/test.d/functions | 21 ++++++++++++++++---
> >  1 file changed, 18 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> > index 2a4f16fc9819..8393b1c06027 100644
> > --- a/tools/testing/selftests/ftrace/test.d/functions
> > +++ b/tools/testing/selftests/ftrace/test.d/functions
> > @@ -15,14 +15,29 @@ reset_tracer() { # reset the current tracer
> >      echo nop > current_tracer
> >  }
> >  
> > -reset_trigger() { # reset all current setting triggers
> > -    grep -v ^# events/*/*/trigger |
> > +reset_trigger_file() {
> > +    # remove action triggers first
> > +    grep -H ':on[^:]*(' $@ |
> > +    while read line; do
> > +        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> > +	file=`echo $line | cut -f1 -d:`
> > +	echo "!$cmd" >> $file
> > +    done
> > +    grep -Hv ^# $@ |
> >      while read line; do
> >          cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> > -	echo "!$cmd" > `echo $line | cut -f1 -d:`
> > +	file=`echo $line | cut -f1 -d:`
> > +	echo "!$cmd" > $file
> >      done
> >  }
> >  
> > +reset_trigger() { # reset all current setting triggers
> > +    if [ -d events/synthetic ]; then
> > +        reset_trigger_file events/synthetic/*/trigger
> > +    fi
> > +    reset_trigger_file events/*/*/trigger
> > +}
> > +
> >  reset_events_filter() { # reset all current setting filters
> >      grep -v ^none events/*/*/filter |
> >      while read line; do
> > -- 
> > 2.17.0
> > 
> >   
> 
>