linux-kernel - Re: [PATCH 11/12] locking/mutex: Revive fast functions for CONFIG_LOCK

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: <20220209084041.GJ23216@worktop.programming.kicks-ass.net>
Date:   Wed, 9 Feb 2022 09:40:41 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>, Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Steven Rostedt <rostedt@...dmis.org>,
        Byungchul Park <byungchul.park@....com>,
        "Paul E. McKenney" <paul.mckenney@...aro.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Radoslaw Burny <rburny@...gle.com>
Subject: Re: [PATCH 11/12] locking/mutex: Revive fast functions for
 CONFIG_LOCK_TRACEPOINTS

On Tue, Feb 08, 2022 at 10:42:07AM -0800, Namhyung Kim wrote:
> I'm not entirely sure why it removed the fast versions when lockdep is
> on.  It seems easy to add the required annotation when the fast
> version is succeeded as far as the tracpoints are concerned.

IIRC it was something like, lockdep depends on MUTEX_DEBUG and that in
turn relied on not having the fast path enabled. MUTEX_DEBUG used to
always take the wait_lock to ensure the debug state is consistent with
the lock state.