Received-SPF: pass (google.com: domain of linux-kernel+bounces-175849-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Fri, 10 May 2024 06:58:50 -0700
From: "Paul E. McKenney" <paulmck@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>, RCU <rcu@vger.kernel.org>,
	Neeraj upadhyay <Neeraj.Upadhyay@amd.com>,
	Boqun Feng <boqun.feng@gmail.com>, Hillf Danton <hdanton@sina.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 25/48] rcu: Mark writes to rcu_sync ->gp_count field
Message-ID: <25a55ddc-caa0-4b5d-baa4-87782e0a002c@paulmck-laptop>
Reply-To: paulmck@kernel.org
References: <20240507093530.3043-1-urezki@gmail.com>
 <20240507093530.3043-26-urezki@gmail.com>
 <ZjpAsYJIfzYSKgdA@redhat.com>
 <4c9e89b5-c981-4809-8bc2-247563ce04e9@paulmck-laptop>
 <20240510131849.GB24764@redhat.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240510131849.GB24764@redhat.com>

On Fri, May 10, 2024 at 03:18:50PM +0200, Oleg Nesterov wrote:
> On 05/07, Paul E. McKenney wrote:
> >
> > By the stricter data-race rules used in RCU code [1],
> ...
> > [1] https://docs.google.com/document/d/1FwZaXSg3A55ivVoWffA9iMuhJ3_Gmj_E494dLYjjyLQ/edit?usp=sharing
> 
> I am getting more and more confused...
> 
> Does this mean that KCSAN/etc treats the files in kernel/rcu/
> differently than the "Rest of Kernel"? Or what?

Yes.

> And how is it enforced?

By me running rcutorture with KCSAN with the Kconfig options listed in
that docusment.

							Thanx, Paul