linux-kernel - Re: [BUG 2.6.25-rc3] scheduler/hotplug: some processes are dealocked when cpu is set to offline

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]

Date:	Fri, 7 Mar 2008 14:02:20 +0100
From:	"Dmitry Adamushko" <dmitry.adamushko@...il.com>
To:	ego@...ibm.com, "Ingo Molnar" <mingo@...e.hu>
Cc:	"Oleg Nesterov" <oleg@...sign.ru>, "Yi Yang" <yi.y.yang@...el.com>,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"Thomas Gleixner" <tglx@...utronix.de>
Subject: Re: [BUG 2.6.25-rc3] scheduler/hotplug: some processes are dealocked when cpu is set to offline

Hi,

'watchdog' is of SCHED_FIFO class. The standard load-balancer doesn't
move RT tasks between cpus anymore and there is a special mechanism in
scher_rt.c instead (I think, it's .25 material).

So I wonder, whether __migrate_task() is still capable of properly
moving a RT task to another CPU (e.g. for the case when it's in
TASK_RUNNING state) without breaking something in the rt migration
mechanism (or whatever else) that would leave us with a runqueue in
the 'inconsistent' state...
(I've taken a quick look at the relevant code so can't confirm it yet)

maybe it'd be faster if somebody could do a quick test now with the
following line commented out in kernel/softlockup.c :: watchdog()

-         sched_setscheduler(current, SCHED_FIFO, &param);

-- 
Best regards,
Dmitry Adamushko
--
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/