linux-kernel - Re: [PATCH 1/2] locking: Provide a low overhead do_arch_spin

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: <56fe41a0-e2be-03bc-8539-204c3dc801ff@redhat.com>
Date:   Wed, 21 Sep 2022 20:51:13 -0400
From:   Waiman Long <longman@...hat.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] locking: Provide a low overhead do_arch_spin_lock()
 API


On 9/21/22 18:06, Steven Rostedt wrote:
> On Wed, 21 Sep 2022 09:21:51 -0400
> Waiman Long <longman@...hat.com> wrote:
>
>> There are some code paths in the kernel like tracing or rcu where they
>> want to use a spinlock without the lock debugging overhead (lockdep,
>> etc). Provide a do_arch_spin_lock() API with proper preemption disabling
>> and enabling without any debugging or tracing overhead.
>>
>> Signed-off-by: Waiman Long <longman@...hat.com>
> Please don't do this. arch_spin_lock() is very special, and if tracing did
> it wrong, then it needs to be fixed in the tracing code.
>
> Let's not add handlers to make it easier to use arch_spin_lock(). Tracing
> is special and arch_spin_lock() helps keep it from tracing itself.

That makes sense to me. Will remove this patch.

Thanks,
Longman