From: Peter Zijlstra <peterz@infradead.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, mingo@kernel.org,
dhowells@redhat.com
Subject: Re: [PATCH locking/Documentation 1/2] Add note of release-acquire store vulnerability
Date: Fri, 30 Sep 2016 10:53:34 +0200 [thread overview]
Message-ID: <20160930085334.GE5016@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1609291527490.1387-100000@iolanthe.rowland.org>
On Thu, Sep 29, 2016 at 03:36:38PM -0400, Alan Stern wrote:
> > > If you execute P0 and P1 concurrently and one store of each 'wins' the
> > > LWSYNC of either is null and void, and therefore P2 is unordered and can
> > > observe r2==0.
>
> Not so. lwsync instructions cannot be "voided".
I distinctly remember there being a case (smp_wmb()) where the lwsync
would disappear if the store was lost.
next prev parent reply other threads:[~2016-09-30 8:53 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-29 15:54 [PATCH locking/Documentation 1/2] Add note of release-acquire store vulnerability Paul E. McKenney
2016-09-29 15:58 ` Peter Zijlstra
2016-09-29 16:03 ` Will Deacon
2016-09-29 16:17 ` Peter Zijlstra
2016-09-29 16:44 ` Paul E. McKenney
2016-09-29 16:43 ` Paul E. McKenney
2016-09-29 17:10 ` Will Deacon
2016-09-29 17:23 ` Paul E. McKenney
2016-09-29 18:04 ` Paul E. McKenney
2016-09-29 18:10 ` Paul E. McKenney
2016-09-29 18:44 ` Peter Zijlstra
2016-09-29 19:18 ` Paul E. McKenney
2016-09-29 19:36 ` Alan Stern
2016-09-29 20:26 ` Paul E. McKenney
2016-09-30 8:53 ` Peter Zijlstra [this message]
2016-09-30 9:00 ` Peter Zijlstra
2016-09-30 9:57 ` Peter Zijlstra
2016-09-30 12:14 ` Paul E. McKenney
2016-09-30 12:51 ` Peter Zijlstra
2016-09-30 13:35 ` Paul E. McKenney
2016-09-30 5:53 ` Boqun Feng
2016-09-30 9:20 ` Will Deacon
2016-09-30 11:35 ` Paul E. McKenney
2016-09-30 10:25 ` Peter Zijlstra
2016-09-30 12:17 ` Paul E. McKenney
2016-09-30 12:45 ` Peter Zijlstra
2016-09-30 13:10 ` Paul E. McKenney
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