linux-kernel - Re: [PATCH] sched/fair: fix pick_eevdf to always find the correct se

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: <db78e251-acd1-496a-bfcd-202ef1d43f31@samsung.com>
Date:   Fri, 6 Oct 2023 22:15:14 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Mike Galbraith <efault@....de>
Cc:     Biju Das <biju.das.jz@...renesas.com>,
        "bsegall@...gle.com" <bsegall@...gle.com>,
        "bristot@...hat.com" <bristot@...hat.com>,
        "chris.hyser@...cle.com" <chris.hyser@...cle.com>,
        "corbet@....net" <corbet@....net>,
        "dietmar.eggemann@....com" <dietmar.eggemann@....com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "joel@...lfernandes.org" <joel@...lfernandes.org>,
        "joshdon@...gle.com" <joshdon@...gle.com>,
        "juri.lelli@...hat.com" <juri.lelli@...hat.com>,
        "kprateek.nayak@....com" <kprateek.nayak@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mingo@...nel.org" <mingo@...nel.org>,
        "patrick.bellasi@...bug.net" <patrick.bellasi@...bug.net>,
        Pavel Machek <pavel@....cz>, "pjt@...gle.com" <pjt@...gle.com>,
        "qperret@...gle.com" <qperret@...gle.com>,
        "qyousef@...alina.io" <qyousef@...alina.io>,
        "rostedt@...dmis.org" <rostedt@...dmis.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "tim.c.chen@...ux.intel.com" <tim.c.chen@...ux.intel.com>,
        "timj@....org" <timj@....org>,
        "vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
        "youssefesmat@...omium.org" <youssefesmat@...omium.org>,
        "yu.c.chen@...el.com" <yu.c.chen@...el.com>,
        "mgorman@...e.de" <mgorman@...e.de>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH] sched/fair: fix pick_eevdf to always find the correct
 se

On 06.10.2023 21:24, Peter Zijlstra wrote:
> On Fri, Oct 06, 2023 at 05:55:01PM +0200, Peter Zijlstra wrote:
>> And yeah, min_deadline is hosed somehow.
>>
>> migration/28-185     [028] d..2.    70.264274: validate_cfs_rq: --- /
>> migration/28-185     [028] d..2.    70.264277: __print_se: ffff88845cf48080 w: 1024 ve: -58857638 lag: 870381 vd: -55861854 vmd: -66302085 E (11372/tr)
>> migration/28-185     [028] d..2.    70.264280: __print_se:   ffff88810d165800 w: 25 ve: -80323686 lag: 22336429 vd: -41496434 vmd: -66302085 E (-1//autogroup-31)
>> migration/28-185     [028] d..2.    70.264282: __print_se:   ffff888108379000 w: 25 ve: 0 lag: -57987257 vd: 114632828 vmd: 114632828 N (-1//autogroup-33)
>> migration/28-185     [028] d..2.    70.264283: validate_cfs_rq: min_deadline: -55861854 avg_vruntime: -62278313462 / 1074 = -57987256
>>
>> I need to go make dinner (kids hungry), but I'll see if I can figure out
>> how this happens...
> *sigh*, does the below help?

It looks that this fixed the issue. At least I was no longer able to 
reproduce it.

Feel free to add:

Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>

Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

> ---
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 04fbcbda97d5..6a670f119efa 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3632,6 +3747,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
>   		 */
>   		deadline = div_s64(deadline * old_weight, weight);
>   		se->deadline = se->vruntime + deadline;
> +		min_deadline_cb_propagate(&se->run_node, NULL);
>   	}
>   
>   #ifdef CONFIG_SMP
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland