linux-kernel - Re: [PATCH v3 35/51] trace,hardirq: No moar

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Message-ID: <Y8ZiIMHyXX/yW1EI@hirez.programming.kicks-ass.net>
Date:   Tue, 17 Jan 2023 09:53:52 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
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Subject: Re: [PATCH v3 35/51] trace,hardirq: No moar _rcuidle() tracing

On Tue, Jan 17, 2023 at 01:24:46PM +0900, Masami Hiramatsu wrote:
> Hi Peter,
> 
> On Thu, 12 Jan 2023 20:43:49 +0100
> Peter Zijlstra <peterz@...radead.org> wrote:
> 
> > Robot reported that trace_hardirqs_{on,off}() tickle the forbidden
> > _rcuidle() tracepoint through local_irq_{en,dis}able().
> > 
> > For 'sane' configs, these calls will only happen with RCU enabled and
> > as such can use the regular tracepoint. This also means it's possible
> > to trace them from NMI context again.
> > 
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> 
> The code looks good to me. I just have a question about comment.
> 
> > ---
> >  kernel/trace/trace_preemptirq.c |   21 +++++++++++++--------
> >  1 file changed, 13 insertions(+), 8 deletions(-)
> > 
> > --- a/kernel/trace/trace_preemptirq.c
> > +++ b/kernel/trace/trace_preemptirq.c
> > @@ -20,6 +20,15 @@
> >  static DEFINE_PER_CPU(int, tracing_irq_cpu);
> >  
> >  /*
> > + * ...
> 
> Is this intended? Wouldn't you leave any comment here?

I indeed forgot to write the comment before posting, my bad :/ Ingo fixed
it up when he applied.