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Message-ID: <ecd0497e-5623-0bf9-0160-79dca921a0a7@joelfernandes.org>
Date:   Tue, 6 Sep 2022 18:31:59 -0400
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Subject: Re: [PATCH v5 03/18] rcu/tree: Use READ_ONCE() for lockless read of
 rnp->qsmask
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To:     Boqun Feng <boqun.feng@gmail.com>
Cc:     rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
        rushikesh.s.kadam@intel.com, urezki@gmail.com,
        neeraj.iitr10@gmail.com, frederic@kernel.org, paulmck@kernel.org,
        rostedt@goodmis.org, vineeth@bitbyteword.org
References: <20220901221720.1105021-1-joel@joelfernandes.org>
 <20220901221720.1105021-4-joel@joelfernandes.org>
 <YxfJGYP2l0xbxxdr@boqun-archlinux>
From:   Joel Fernandes <joel@joelfernandes.org>
In-Reply-To: <YxfJGYP2l0xbxxdr@boqun-archlinux>
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On 9/6/2022 6:26 PM, Boqun Feng wrote:
> On Thu, Sep 01, 2022 at 10:17:05PM +0000, Joel Fernandes (Google) wrote:
>> The rnp->qsmask is locklessly accessed from rcutree_dying_cpu(). This
>> may help avoid load/store tearing due to concurrent access, KCSAN
> 
> Nit: you can avoid only load tearing with READ_ONCE().
> 

I modified it as you suggested for the next revision, thanks.