From: Peter Zijlstra <peterz@infradead.org>
To: Marco Elver <elver@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>, Qian Cai <cai@lca.pw>,
Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: [PATCH] locking/osq_lock: fix a data race in osq_wait_next
Date: Thu, 30 Jan 2020 14:48:51 +0100 [thread overview]
Message-ID: <20200130134851.GY14914@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CANpmjNNZQsatHexXHm4dXvA0na6r9xMgVD5R+-8d7VXEBRi32w@mail.gmail.com>
On Thu, Jan 30, 2020 at 02:39:38PM +0100, Marco Elver wrote:
> On Wed, 29 Jan 2020 at 19:40, Peter Zijlstra <peterz@infradead.org> wrote:
> > It's probably not terrible to put a READ_ONCE() there; we just need to
> > make sure the compiler doesn't do something stupid (it is known to do
> > stupid when 'volatile' is present).
>
> Maybe we need to optimize READ_ONCE().
I think recent compilers have gotten better at volatile. In part because
of our complaints.
> 'if (data_race(..))' would also work here and has no cost.
Right, that might be the best option.
next prev parent reply other threads:[~2020-01-30 13:48 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 16:38 Qian Cai
2020-01-22 16:59 ` Will Deacon
2020-01-22 17:08 ` Qian Cai
2020-01-22 22:38 ` Marco Elver
2020-01-22 23:54 ` Qian Cai
2020-01-23 9:39 ` Peter Zijlstra
2020-01-28 3:11 ` Qian Cai
2020-01-28 11:46 ` Marco Elver
2020-01-28 12:53 ` Qian Cai
2020-01-28 16:52 ` Peter Zijlstra
2020-01-28 16:56 ` Peter Zijlstra
2020-01-29 0:22 ` Paul E. McKenney
2020-01-29 15:29 ` Marco Elver
2020-01-29 18:40 ` Peter Zijlstra
2020-01-30 13:39 ` Marco Elver
2020-01-30 13:48 ` Peter Zijlstra [this message]
2020-01-31 3:32 ` Qian Cai
2020-01-29 18:49 ` Peter Zijlstra
2020-01-29 19:26 ` Paul E. McKenney
2020-01-23 9:36 ` Peter Zijlstra
2020-01-28 3:12 ` Qian Cai
2020-01-28 8:18 ` Marco Elver
2020-01-28 10:10 ` Qian Cai
2020-01-28 10:29 ` Marco Elver
2020-01-22 17:09 ` Peter Zijlstra
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