linux-kernel - Re: [PATCH v2] sched/fair: Fixes for capacity inversion detection

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: <20221208145825.gt3rsysykqaklrwt@airbuntu>
Date:   Thu, 8 Dec 2022 14:58:25 +0000
From:   Qais Yousef <qyousef@...alina.io>
To:     Dietmar Eggemann <dietmar.eggemann@....com>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Lukasz Luba <lukasz.luba@....com>, Wei Wang <wvw@...gle.com>,
        Xuewen Yan <xuewen.yan94@...il.com>,
        Hank <han.lin@...iatek.com>,
        Jonathan JMChen <Jonathan.JMChen@...iatek.com>
Subject: Re: [PATCH v2] sched/fair: Fixes for capacity inversion detection

On 12/08/22 14:54, Qais Yousef wrote:
> Traversing the Perf Domains requires rcu_read_lock() to be held and is
> conditional on sched_energy_enabled(). rcu_read_lock() is held while in
> load_balance(), add an assert to ensure this is always the case.

Err that should say instead

	Traversing the Perf Domains requires rcu_read_lock() to be held and is
	conditional on sched_energy_enabled(). Ensure right protections applied.

Peter, let me know if you want me to resend with that fixed or happy to apply
yourself.


Thanks!

--
Qais Yousef

> 
> Also skip capacity inversion detection for our own pd; which was an
> error.
> 
> Fixes: 44c7b80bffc3 ("sched/fair: Detect capacity inversion")
> Reported-by: Dietmar Eggemann <dietmar.eggemann@....com>
> Signed-off-by: Qais Yousef (Google) <qyousef@...alina.io>
> ---
> 
> Changes in v2:
> 
> 	* Make sure to hold rcu_read_lock() as we need it's not held in all
> 	  paths (thanks Dietmar!)