linux-kernel - Re: [PATCH 6/7] osnoise: handle quiescent states for PREEMPT

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: <20241011073602.7EmDWFkc@linutronix.de>
Date: Fri, 11 Oct 2024 09:36:02 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Ankur Arora <ankur.a.arora@...cle.com>
Cc: linux-kernel@...r.kernel.org, peterz@...radead.org, tglx@...utronix.de,
	paulmck@...nel.org, mingo@...nel.org, juri.lelli@...hat.com,
	vincent.guittot@...aro.org, dietmar.eggemann@....com,
	rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
	vschneid@...hat.com, frederic@...nel.org, efault@....de
Subject: Re: [PATCH 6/7] osnoise: handle quiescent states for PREEMPT_RCU=n,
 PREEMPTION=y

On 2024-10-10 10:50:29 [-0700], Ankur Arora wrote:
> > PREEMPTION=y, PREEMPT_RCU=n should not be possible.
> 
> That's a statement. Is there an argument here?

For my taste you should describe in your cover letter the actual problem
and what you intend to do about it. Then you should a series addressing
this issue which would probably qualify for all patches in your series
but 7/7 (the PPC bits for lazy preempt). 7/7 should have been the part
where you make possible to make PREEMPT_RCU selectable.

Based on my understanding so far you (or Paul) want to make PREEMPT_RCU
selectable if PREEMPT_LAZY is enabled _or_ if DYNAMIC_PREEMPT is enabled
with the NONE or VOLUNTARY model.

This series as-is made no sense to me until Peter made the snippet where
you could indeed make PREEMPT_RCU selectable.

Sebastian