linux-kernel - Re: [PATCH v3 6/6] pid: drop irq disablement around pidmap

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: <Z56ZZpmAbRCIeI7D@casper.infradead.org>
Date: Sat, 1 Feb 2025 22:00:06 +0000
From: Matthew Wilcox <willy@...radead.org>
To: David Laight <david.laight.linux@...il.com>
Cc: Mateusz Guzik <mjguzik@...il.com>, ebiederm@...ssion.com,
	oleg@...hat.com, brauner@...nel.org, akpm@...ux-foundation.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock

On Sat, Feb 01, 2025 at 09:51:05PM +0000, David Laight wrote:
> I'm not sure what you mean.
> Disabling interrupts isn't as cheap as it ought to be, but probably isn't
> that bad.

Time it.  You'll see.

> > So while this is indeed a tradeoff, as I understand the sane default
> > is to *not* disable interrupts unless necessary.
> 
> I bet to differ.

You're wrong.  It is utterly standard to take spinlocks without
disabling IRQs.  We do it all over the kernel.  If you think that needs
to change, then make your case, don't throw a driveby review.

And I don't mean by arguing.  Make a change, measure the difference.