linux-kernel - Re: [RFC PATCH v15 2/7] locking/mutex: Rework task_struct::blocked

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: <CANDhNCofYzVrdND+iPBU64feim+Cqi+bOCp-iaWJ8=HkAcDJ2A@mail.gmail.com>
Date: Wed, 19 Mar 2025 10:49:10 +0100
From: John Stultz <jstultz@...gle.com>
To: Lance Yang <ioworker0@...il.com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Steven Rostedt <rostedt@...dmis.org>, 
	LKML <linux-kernel@...r.kernel.org>, Peter Zijlstra <peterz@...radead.org>, 
	Joel Fernandes <joelagnelf@...dia.com>, Qais Yousef <qyousef@...alina.io>, 
	Ingo Molnar <mingo@...hat.com>, Juri Lelli <juri.lelli@...hat.com>, 
	Vincent Guittot <vincent.guittot@...aro.org>, Dietmar Eggemann <dietmar.eggemann@....com>, 
	Valentin Schneider <vschneid@...hat.com>, Ben Segall <bsegall@...gle.com>, 
	Zimuzo Ezeozue <zezeozue@...gle.com>, Mel Gorman <mgorman@...e.de>, Will Deacon <will@...nel.org>, 
	Waiman Long <longman@...hat.com>, Boqun Feng <boqun.feng@...il.com>, 
	"Paul E. McKenney" <paulmck@...nel.org>, Metin Kaya <Metin.Kaya@....com>, 
	Xuewen Yan <xuewen.yan94@...il.com>, K Prateek Nayak <kprateek.nayak@....com>, 
	Thomas Gleixner <tglx@...utronix.de>, Daniel Lezcano <daniel.lezcano@...aro.org>, 
	Suleiman Souhlal <suleiman@...gle.com>, kernel-team@...roid.com, hikalium@...gle.com, 
	amaindex@...look.com
Subject: Re: [RFC PATCH v15 2/7] locking/mutex: Rework task_struct::blocked_on

On Tue, Mar 18, 2025 at 4:33 PM Lance Yang <ioworker0@...il.com> wrote:
>
> When’s the next version expected? I intend to send a new version out
> soon, and it’d be great if you could include it in the next version ;)

Yeah, I've pulled in your old version already, but I'll update my tree
with your new one.  Between conf travel and vacation, it might be
April before I get v16 out.

Most likely I'll be moving much of linux/hung_task.h into
linux/sched.h to get generic accessors to setting and clearing the
task blocked-on relationship (so its not just tied to the hung task
debug logic). Then for proxy I just need to integrate it with the
additional blocked_on_state that is used to determine if the
(previously blocked, but left on the rq) task is runnable or not.

> Also, since we have similar use cases, it might make sense to use
> the same field to store the lock, encoding the lock type in the LSB as
> Masami suggested.

Yep. Agreed.  As I mentioned earlier, proxy only works with mutexes at
the moment, but I do intend to expand that once we have the core proxy
logic well tested upstream, so the multi-type blocked-on relationship
is really useful to have.

thanks!
-john