linux-kernel - Re: [PATCH v3 04/25] kcsan: Add core support for a subset of weak memory modeling

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: <CANpmjNM0X1iAgz4vHTH4FSzdWdr1PiQQnoyFt-zoT2_VonFvVA@mail.gmail.com>
Date:   Sat, 4 Dec 2021 00:42:02 +0100
From:   Marco Elver <elver@...gle.com>
To:     paulmck@...nel.org
Cc:     Alexander Potapenko <glider@...gle.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Borislav Petkov <bp@...en8.de>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Ingo Molnar <mingo@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Waiman Long <longman@...hat.com>,
        Will Deacon <will@...nel.org>, kasan-dev@...glegroups.com,
        linux-arch@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, llvm@...ts.linux.dev, x86@...nel.org
Subject: Re: [PATCH v3 04/25] kcsan: Add core support for a subset of weak
 memory modeling

On Fri, 3 Dec 2021 at 22:09, Paul E. McKenney <paulmck@...nel.org> wrote:
[...]
> A few quick tests located the following:
>
> [    0.635383] INFO: trying to register non-static key.
> [    0.635804] The code is fine but needs lockdep annotation, or maybe
> [    0.636194] you didn't initialize this object before use?
> [    0.636194] turning off the locking correctness validator.
> [    0.636194] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-rc1+ #3208
[...]
> When running without the new patch series, this splat does not appear.
>
> Do I need a toolchain upgrade?  I see the Clang 14.0 in the cover letter,
> but that seems to apply only to non-x86 architectures.
>
> $ clang-11 -v
> Ubuntu clang version 11.1.0-++20210805102428+1fdec59bffc1-1~exp1~20210805203044.169

Good catch! That would be lockdep telling me off for putting test
locks on the stack. :-/

I thought I had tested this with lockdep, but it seems the set of
semi-automated tests I run didn't (yet) generate a config with
KCSAN_WEAK_MEMORY + LOCKDEP.

This should be fixed by:
https://lkml.kernel.org/r/20211203233817.2815340-1-elver@google.com

Thanks,
-- Marco