linux-kernel - Re: [PATCH RFC] drivers/core: Replace lockdep_set_novalidate

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: <Y+vsNnP9PPXPNz+M@moria.home.lan>
Date:   Tue, 14 Feb 2023 15:16:54 -0500
From:   Kent Overstreet <kent.overstreet@...ux.dev>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Alan Stern <stern@...land.harvard.edu>,
        Kent Overstreet <kent.overstreet@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Coly Li <colyli@...e.de>,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        syzkaller <syzkaller@...glegroups.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        USB list <linux-usb@...r.kernel.org>,
        Hillf Danton <hdanton@...a.com>
Subject: Re: [PATCH RFC] drivers/core: Replace lockdep_set_novalidate_class()
 with unique class keys

On Tue, Feb 14, 2023 at 12:05:27PM +0100, Peter Zijlstra wrote:
> This is lock order per decree, if you get the order function wrong
> lockdep will not see the inversion but you *will* deadlock.

Yeah, that's what I mean. Given that a subclass isn't a fixed thing you
assign to a lock, just something you magic up as needed - I just don't
see what this gets us?

Why not just tell lockdep what the order function is directly?

(I know, I've been saying I'd write a patch for this, I'll get around to
it, I swear :)