linux-kernel - Re: [PATCH] stop_machine: Avoid potential race behaviour of multi_stop

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]

Message-ID: <20231017131435.GA1599@noisy.programming.kicks-ass.net>
Date:   Tue, 17 Oct 2023 15:14:35 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Mark Rutland <mark.rutland@....com>
Cc:     Rong Tao <rtoax@...mail.com>, elver@...gle.com, tglx@...utronix.de,
        Rong Tao <rongtao@...tc.cn>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] stop_machine: Avoid potential race behaviour of
 multi_stop_data::state

On Tue, Oct 17, 2023 at 11:24:40AM +0100, Mark Rutland wrote:

> That said, if we really want to avoid the non-atomic read, it's probably better
> to have multi_cpu_stop() pass curstate as a paramter to ack_state. That or fold
> ack_state() into multi_cpu_stop() and use curstate directly.

Right. Also, that smp_wmb() needs a comment. Or perhaps
smp_store_release().