linux-kernel - Re: [PATCH RT] fix rt-task scheduling issue

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: <1191903533.4281.51.camel@ghaskins-t60p.haskins.net>
Date:	Tue, 09 Oct 2007 00:18:53 -0400
From:	Gregory Haskins <ghaskins@...ell.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Mike Kravetz <kravetz@...ibm.com>, Ingo Molnar <mingo@...e.hu>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RT] fix rt-task scheduling issue

Hi Guys,
  Nice find!  Comment inline..

(adding linux-rt-users)

 for reference to

 http://lkml.org/lkml/2007/10/8/252

On Mon, 2007-10-08 at 22:46 -0400, Steven Rostedt wrote:
> Index: linux-2.6.23-rc9-rt2/kernel/sched.c
> ===================================================================
> --- linux-2.6.23-rc9-rt2.orig/kernel/sched.c
> +++ linux-2.6.23-rc9-rt2/kernel/sched.c
> @@ -2207,7 +2207,7 @@ static inline void finish_task_switch(st
>  	 * If we pushed an RT task off the runqueue,
>  	 * then kick other CPUs, they might run it:
>  	 */
> -	if (unlikely(rt_task(current) && prev->se.on_rq && rt_task(prev))) {
> +	if (unlikely(rt_task(current) && rq->rt_nr_running > 1)) {
>  		schedstat_inc(rq, rto_schedule);
>  		smp_send_reschedule_allbutself_cpumask(current->cpus_allowed);

the current->cpus_allowed I think probably should have been
"prev->cpus_allowed" in the original code?  However, in light of the new
findings with this bug Mike found, this should probably be sent to
allbutself() without the mask since you don't know what could have been
queued behind you.

Unless I am missing something?

Regards,
-Greg


-
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/