linux-kernel - Re: [PATCH] stop_machine: avoid potential race behaviour

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 8 Oct 2019 10:36:37 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Mark Rutland <mark.rutland@....com>
Cc:     linux-kernel@...r.kernel.org, Marco Elver <elver@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] stop_machine: avoid potential race behaviour

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.