linux-kernel - Re: [PATCH 2/3] lockdep: clarify size for LOCKDEP_*

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: <e378ac65-73cc-4829-b605-f164c67dc5ae@redhat.com>
Date: Tue, 6 Aug 2024 10:52:52 -0400
From: Waiman Long <longman@...hat.com>
To: Carlos Llamas <cmllamas@...gle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org,
 kernel-team@...roid.com, Peter Zijlstra <peterz@...radead.org>,
 Boqun Feng <boqun.feng@...il.com>, Ingo Molnar <mingo@...hat.com>,
 Will Deacon <will@...nel.org>
Subject: Re: [PATCH 2/3] lockdep: clarify size for LOCKDEP_*_BITS configs


On 8/6/24 10:47, Carlos Llamas wrote:
> On Mon, Aug 05, 2024 at 09:36:43PM -0400, Waiman Long wrote:
>> Many kernel developers understand that BITS refers to a size of 2^n. Besides
>> LOCKDEP, there are also many instances of such use in other kconfig entries.
>> It can be a bit odd to explicitly state that just for LOCKDEP.
>>
>> Cheers,
>> Longman
> Right, and similar to BITS there is SHIFT, which is also a common way to
> specify the 2^n values. I'd point out though, that it is also common to
> clarify the "power of two" explicitly. To name a few examples that are
> doing so: SECURITY_SELINUX_SIDTAB_HASH_BITS, NODES_SHIFT, CMA_ALIGNMENT,
> IP_VS_SH_TAB_BITS, LOG_BUF_SHIFT but there is more.
>
> Perhaps this is because the audience for these configs is not always a
> kernel developer?
>
> Anyway, this is pretty much a trivial patch to address Andrew's comment
> below. But let me know if you think I should drop it, it seems to me it
> can be helpful.
>
>    [...]
>    btw, the help text "Bitsize for MAX_LOCKDEP_CHAINS" is odd.  What's a
>    bitsize?  Maybe "bit shift count for..." or such.

I am not against this patch. Currently I am neutral. Let's see what 
Boqun think about it.

Cheers,
Longman