linux-kernel - Re: [PATCH] stop_machine: Mark functions as notrace

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Message-ID: <20201021154456.GM3249@paulmck-ThinkPad-P72>
Date:   Wed, 21 Oct 2020 08:44:56 -0700
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Zong Li <zong.li@...ive.com>, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
        joel@...lfernandes.org, vincent.whitchurch@...s.com,
        tglx@...utronix.de, paul.walmsley@...ive.com,
        palmerdabbelt@...gle.com, guoren@...nel.org, atishp@...shpatra.org,
        mhiramat@...nel.org, greentime.hu@...ive.com,
        colin.king@...onical.com, rcu@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH] stop_machine: Mark functions as notrace

On Wed, Oct 21, 2020 at 10:15:22AM -0400, Steven Rostedt wrote:
> On Wed, 21 Oct 2020 10:12:16 -0400
> Steven Rostedt <rostedt@...dmis.org> wrote:
> 
> > > Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield")
> > > Fixes: 366237e7b083 ("stop_machine: Provide RCU quiescent state in
> > > multi_cpu_stop()")  
> > 
> > I really do not like to add "notrace" to core functions because a single
> > architecture has issues with it. Why does RISCV have problems with these
> > functions but no other architecture does?
> > 
> > NACK from me until it is shown that these are issues for a broader set of
> > architectures.
> 
> After looking at the two above fixes, I take back my NACK ;-)
> 
> One of them duplicates an already notraced function, so that looks fine.
> The other makes a static function global, which could cause issues as well.
> 
> After further review:
> 
> Acked-by: Steven Rostedt (VMware) <rostedt@...dmis.org>

If someone else would like to take this:

Acked-by: Paul E. McKenney <paulmck@...nel.org>

Or let me know if you would like me to take it, target v5.11.

							Thanx, Paul