linux-kernel - Re: [PATCH] cpufreq: schedutil: Don't ignore limit changes when util is unchanged

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] [day] [month] [year] [list]

Message-ID: <CAJZ5v0hTb6+cNA4fP6ovg2M3woLjid-fMy8jAp8S--=tv+7f4Q@mail.gmail.com>
Date: Fri, 11 Apr 2025 12:30:48 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Xuewen Yan <xuewen.yan94@...il.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Sultan Alsawaf <sultan@...neltoast.com>, 
	Stephan Gerhold <stephan.gerhold@...aro.org>, Viresh Kumar <viresh.kumar@...aro.org>, 
	Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Juri Lelli <juri.lelli@...hat.com>, Vincent Guittot <vincent.guittot@...aro.org>, 
	Dietmar Eggemann <dietmar.eggemann@....com>, Steven Rostedt <rostedt@...dmis.org>, 
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>, 
	Valentin Schneider <vschneid@...hat.com>, Christian Loehle <christian.loehle@....com>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: schedutil: Don't ignore limit changes when util
 is unchanged

On Fri, Apr 11, 2025 at 10:22 AM Xuewen Yan <xuewen.yan94@...il.com> wrote:
>
> ...
> >
> > AFAICS, after this code modification, a limit change may be missed due
> > to a possible race with sugov_limits() which cannot happen if
> > sg_policy->limits_changed is only cleared when it is set before
> > updating sg_policy->need_freq_update.
> >
> could the following patch prevent the race?
>
> https://lore.kernel.org/all/CAB8ipk_Ayqmh=Ch2aH2c+i-q+qdiQ317VBH1kOHYN=R9dt6LOw@mail.gmail.com/

The first hunk is essentially a partial revert of the problematic
commit, but I'm not sure what you want to achieve with the second one.