Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE

From: Zhouyi Zhou <zhouzhouyi@gmail.com>
To: paulmck@kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Josh Triplett <josh@joshtriplett.org>,
	rostedt <rostedt@goodmis.org>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	"Joel Fernandes, Google" <joel@joelfernandes.org>,
	rcu <rcu@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	apw@canonical.com, joe@perches.com, ast@kernel.org,
	daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
	songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
	kpsingh@kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
Date: Thu, 15 Jul 2021 16:45:04 +0800	[thread overview]
Message-ID: <CAABZP2xDNtjZew=Rr7QvEDX7jnVCcE+JFpSDxiQ4yNPUE6kj-g@mail.gmail.com> (raw)
In-Reply-To: <20210715035149.GI4397@paulmck-ThinkPad-P17-Gen-1>

On Thu, Jul 15, 2021 at 11:51 AM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Wed, Jul 14, 2021 at 12:44:36PM +0800, Zhouyi Zhou wrote:
> > On Tue, Jul 13, 2021 at 11:19 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > >
> > > On Tue, Jul 13, 2021 at 06:18:12AM -0700, Paul E. McKenney wrote:
> > > > On Tue, Jul 13, 2021 at 09:09:04AM -0400, Mathieu Desnoyers wrote:
> > > > > ----- On Jul 13, 2021, at 12:16 AM, paulmck paulmck@kernel.org wrote:
> > > > >
> > > > > > On Tue, Jul 13, 2021 at 08:56:45AM +0800, zhouzhouyi@gmail.com wrote:
> > > > > >> From: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > >>
> > > > > >> Hi Paul,
> > > > > >>
> > > > > >> During my studying of RCU, I did a grep in the kernel source tree.
> > > > > >> I found there are 3 places where the macro name CONFIG_TASKS_RCU_TRACE
> > > > > >> should be CONFIG_TASKS_TRACE_RCU instead.
> > > > > >>
> > > > > >> Without memory fencing, the idle/userspace task inspection may not
> > > > > >> be so accurate.
> > > > > >>
> > > > > >> Thanks for your constant encouragement for my studying.
> > > > > >>
> > > > > >> Best Wishes
> > > > > >> Zhouyi
> > > > > >>
> > > > > >> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > >
> > > > > > Good eyes, and those could cause real bugs, so thank you!
> > > > >
> > > > > Hi Paul,
> > > > >
> > > > > This makes me wonder: what is missing testing-wise in rcutorture to
> > > > > catch those issues with testing before they reach mainline ?
> > > >
> > > > My guess:  Running on weakly ordered architectures.  ;-)
> > >
> > > And another guess:  A tool that identifies use of Kconfig options
> > > that are not defined in any Kconfig* file.
> > Based on Paul's second guess ;-),  I did a small research, and I think
> > the best answer is to modify scripts/checkpatch.pl. We modify checkpatch.pl
> > to identify use of Kconfig options that are not defined in any Kconfig* file.
> >
> > As I am a C/C++ programmer, I would be glad to take some time to learn
> > perl (checkpatch is implented in perl) first if no other volunteer is
> > about to do it ;-)
>
> I haven't heard anyone else volunteer.  ;-)
>
> Others might have opinions on where best to implement these checks,
> but I must confess that I have not given it much thought.
I recklessly cc the maintainers of checkpatch.pl without your
permission to see others' opion,
and I begin to study perl at the same time, after all, learning
something is always good ;-)
>
>                                                         Thanx, Paul
Best Wishes
Zhouyi