linux-kernel - Re: [PATCH] sched/fair: Fix overutilized update in enqueue_task

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: <20201113081819.GB2628@hirez.programming.kicks-ass.net>
Date:   Fri, 13 Nov 2020 09:18:19 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Quentin Perret <qperret@...gle.com>
Cc:     Ingo Molnar <mingo@...hat.com>, 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>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Quentin Perret <qperret@...rret.net>,
        "open list:SCHEDULER" <linux-kernel@...r.kernel.org>,
        kernel-team@...roid.com, Rick Yiu <rickyiu@...gle.com>
Subject: Re: [PATCH] sched/fair: Fix overutilized update in
 enqueue_task_fair()

On Thu, Nov 12, 2020 at 11:12:01AM +0000, Quentin Perret wrote:
> enqueue_task_fair() attempts to skip the overutilized update for new
> tasks as their util_avg is not accurate yet. However, the flag we check
> to do so is overwritten earlier on in the function, which makes the
> condition pretty much a nop.
> 
> Fix this by saving the flag early on.
> 
> Fixes: 2802bf3cd936 ("sched/fair: Add over-utilization/tipping point
> indicator")

Fix that wrapping for you :-)

> Reported-by: Rick Yiu <rickyiu@...gle.com>
> Signed-off-by: Quentin Perret <qperret@...gle.com>

Thanks!