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From: Peter Zijlstra <peterz@infradead.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, Marco Elver <elver@google.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] stop_machine: avoid potential race behaviour
Date: Tue, 8 Oct 2019 10:36:37 +0200	[thread overview]
Message-ID: <20191008083637.GI2294@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191007104536.27276-1-mark.rutland@arm.com>

On Mon, Oct 07, 2019 at 11:45:36AM +0100, Mark Rutland wrote:
> Both multi_cpu_stop() and set_state() access multi_stop_data::state
> racily using plain accesses. These are subject to compiler
> transformations which could break the intended behaviour of the code,
> and this situation is detected by KCSAN on both arm64 and x86 (splats
> below).

I really don't think there is anything the compiler can do wrong here.

That is, I'm thinking I'd like to get this called out as a false-positive.

That said, the patch looks obviously fine and will help with the
validation effort so no real objection there.

  parent reply	other threads:[~2019-10-08  8:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07 10:45 Mark Rutland
2019-10-07 11:01 ` Marco Elver
2019-10-08  8:36 ` Peter Zijlstra [this message]
2019-10-14 10:09   ` Mark Rutland
2019-10-17 10:49 ` [tip: core/urgent] stop_machine: Avoid " tip-bot2 for Mark Rutland

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