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Date:   Wed, 1 Apr 2020 08:38:24 -0700
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     Joe Perches <joe@perches.com>
Cc:     Marco Elver <elver@google.com>,
        Andrew Morton <akpm@linux-foundation.org>, dvyukov@google.com,
        glider@google.com, andreyknvl@google.com,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        apw@canonical.com, Will Deacon <will@kernel.org>
Subject: Re: [PATCH] checkpatch: Warn about data_race() without comment
Message-ID: <20200401153824.GX19865@paulmck-ThinkPad-P72>
Reply-To: paulmck@kernel.org
References: <20200401101714.44781-1-elver@google.com>
 <9de4fb8fa1223fc61d6d8d8c41066eea3963c12e.camel@perches.com>
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On Wed, Apr 01, 2020 at 08:17:52AM -0700, Joe Perches wrote:
> On Wed, 2020-04-01 at 12:17 +0200, Marco Elver wrote:
> > Warn about applications of data_race() without a comment, to encourage
> > documenting the reasoning behind why it was deemed safe.
> []
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> []
> > @@ -5833,6 +5833,14 @@ sub process {
> >  			}
> >  		}
> >  
> > +# check for data_race without a comment.
> > +		if ($line =~ /\bdata_race\s*\(/) {
> > +			if (!ctx_has_comment($first_line, $linenr)) {
> > +				WARN("DATA_RACE",
> > +				     "data_race without comment\n" . $herecurr);
> > +			}
> > +		}
> > +
> >  # check for smp_read_barrier_depends and read_barrier_depends
> >  		if (!$file && $line =~ /\b(smp_|)read_barrier_depends\s*\(/) {
> >  			WARN("READ_BARRIER_DEPENDS",
> 
> Sensible enough but it looks like ctx_has_comment should
> be updated to allow c99 comments too, but that should be
> a separate change from this patch.
> 
> Otherwise, this style emits a message:
> 
> WARNING: data_race without comment
> #135: FILE: kernel/rcu/tasks.h:135:
> +	int i = data_race(rtp->gp_state); // Let KCSAN detect update races
> 

Yes, please!

							Thanx, Paul