linux-kernel - Re: Bug in scheduler when using rt

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: <AANLkTinfGL3=8LKTx3gCg_V9DfXi44E2PxPd-vQVfALU@mail.gmail.com>
Date:	Wed, 19 Jan 2011 14:09:28 +0800
From:	Yong Zhang <yong.zhang0@...il.com>
To:	Mike Galbraith <efault@....de>
Cc:	Peter Zijlstra <peterz@...radead.org>, samu.p.onkalo@...ia.com,
	mingo@...e.hu,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	tglx <tglx@...utronix.de>
Subject: Re: Bug in scheduler when using rt_mutex

On Wed, Jan 19, 2011 at 1:40 PM, Mike Galbraith <efault@....de> wrote:
> On Wed, 2011-01-19 at 12:35 +0800, Yong Zhang wrote:
>
>> cfs_rq->curr != se is always true.
>
> If that were always true, we'd illegally enqueue a running task.

I'm sorry that I'm not express myself correctly.

The conclusion of (cfs_rq->curr != se is always true) is not
self-contained. IOW, it's based on one condition which is
(task_of(se) != rq->curr). So what I want to say is:
task_of(se) != rq->curr    ==>   cfs_rq_of(se)->curr != se
So,
         !running                   ==>   cfs_rq_of(se)->curr != se

Is this more clear?

Thanks,
Yong

-- 
Only stand for myself
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/