linux-kernel - Re: [PATCH 2/7] sched: change wake_up_bit() and related function to expect unsigned long *

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-id: <172648729127.17050.15543415823867299910@noble.neil.brown.name>
Date: Mon, 16 Sep 2024 21:48:11 +1000
From: "NeilBrown" <neilb@...e.de>
To: "Peter Zijlstra" <peterz@...radead.org>
Cc: "Ingo Molnar" <mingo@...hat.com>,
 "Linus Torvalds" <torvalds@...ux-foundation.org>,
 "Jens Axboe" <axboe@...nel.dk>, linux-kernel@...r.kernel.org,
 linux-fsdevel@...r.kernel.org, linux-block@...r.kernel.org
Subject: Re: [PATCH 2/7] sched: change wake_up_bit() and related function to
 expect unsigned long *

On Mon, 16 Sep 2024, Peter Zijlstra wrote:
> On Mon, Aug 26, 2024 at 04:30:59PM +1000, NeilBrown wrote:
> > wake_up_bit() currently allows a "void *".  While this isn't strictly a
> > problem as the address is never dereferenced, it is inconsistent with
> > the corresponding wait_var_event() which requires "unsigned long *" and
> > does dereference the pointer.
> 
> I'm having trouble parsing this. The way I read it, you're contradicting
> yourself. Where does wait_var_event() require 'unsigned long *' ?

Sorry, that is meant so as "the corresponding wait_on_bit()".


> 
> > And code that needs to wait for a change in something other than an
> > unsigned long would be better served by wake_up_var().
> 
> This, afaict the whole var thing is size invariant. It only cares about
> the address.
> 

Again - wake_up_bit().  Sorry - bits are vars were swimming around my
brain and I didn't proof-read properly.

This patch is all "bit", no "var".

NeilBrown