linux-kernel - Re: [PATCH 6.0.y / 6.1.y] x86/split_lock: Add sysctl to control the misery mode

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: <Y6BD9W7hk4CjhSdh@hirez.programming.kicks-ass.net>
Date:   Mon, 19 Dec 2022 11:59:01 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Greg KH <greg@...ah.com>
Cc:     "Guilherme G. Piccoli" <gpiccoli@...lia.com>,
        stable@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, corbet@....net,
        kernel-dev@...lia.com, kernel@...ccoli.net, fenghua.yu@...el.com,
        joshua@...ggi.es, pgofman@...eweavers.com, pavel@...x.de,
        pgriffais@...vesoftware.com, zfigura@...eweavers.com,
        cristian.ciocaltea@...labora.com,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        Andre Almeida <andrealmeid@...lia.com>
Subject: Re: [PATCH 6.0.y / 6.1.y] x86/split_lock: Add sysctl to control the
 misery mode

On Mon, Dec 19, 2022 at 11:17:39AM +0100, Greg KH wrote:

> What specific programs have this problem and what are the exact results
> of it?

IIRC it was God of War (2018) that triggered this initially. But it's
possible more games were found to tickle this specific thing. Since it's
binary only gunk that is unlikely to ever get fixed we need something to
allow for it.

(slow motion Kratos yelling B...o...y...)

> Also, this is really a new feature and not really a "fix", but one could
> argue a lot that this is a "resolve a performance problem" if you want
> to and have the numbers to back it up  {hint}

Right, there were some, they should indeed have been included.