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Date:   Wed, 5 Jun 2019 23:05:11 -0700
From:   "Paul E. McKenney" <paulmck@linux.ibm.com>
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     Alan Stern <stern@rowland.harvard.edu>,
        Boqun Feng <boqun.feng@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Fengguang Wu <fengguang.wu@intel.com>, LKP <lkp@01.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Netdev <netdev@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Andrea Parri <andrea.parri@amarulasolutions.com>,
        Luc Maranget <luc.maranget@inria.fr>,
        Jade Alglave <j.alglave@ucl.ac.uk>
Subject: Re: rcu_read_lock lost its compiler barrier
Reply-To: paulmck@linux.ibm.com
References: <20190603200301.GM28207@linux.ibm.com>
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 <20190606045109.zjfxxbkzq4wb64bj@gondor.apana.org.au>
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On Thu, Jun 06, 2019 at 12:51:09PM +0800, Herbert Xu wrote:
> On Tue, Jun 04, 2019 at 10:44:18AM -0400, Alan Stern wrote:
> >
> > Currently the LKMM says the test is allowed and there is a data race, 
> > but this answer clearly is wrong since it would violate the RCU 
> > guarantee.
> 
> Thank you! This is what I tried to say all along in this thread
> but you expressed it in a much better way :)

In case you were wondering, the reason that I was giving you such
a hard time was that from what I could see, you were pushing for no
{READ,WRITE}_ONCE() at all.  ;-)

							Thanx, Paul