linux-kernel - Re: regression from softlockup fix

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] [day] [month] [year] [list]

Date:	Mon, 19 Nov 2007 20:03:56 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
Cc:	David Miller <davem@...emloft.net>, linux-kernel@...r.kernel.org,
	gregkh@...e.de, Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: regression from softlockup fix


* Jeremy Fitzhardinge <jeremy@...p.org> wrote:

> I thought the timer code kicked the watchdog after waking up after a 
> long sleep anyway?  At one point I was looking into a mechanism to 
> temporarily disable the watchdog during a wait for a timer event, but 
> it got complex - and I thought - unnecessary.
> 
> Specifically this in kernel/time/timekeeping.c:
> 
> 		/*
> 		 * When we are idle and the tick is stopped, we have to touch
> 		 * the watchdog as we might not schedule for a really long
> 		 * time. This happens on complete idle SMP systems while
> 		 * waiting on the login prompt. We also increment the "start of
> 		 * idle" jiffy stamp so the idle accounting adjustment we do
> 		 * when we go busy again does not account too much ticks.
> 		 */
> 		if (ts->tick_stopped) {
> 			touch_softlockup_watchdog();
> 			ts->idle_jiffies++;
> 		}
> 
> Or does this happen on the sleep path?  If so, wouldn't the right fix 
> to be this on the wakeup path?

yep, i guess this would do the trick. David, could you try it perhaps 
(let me know if i should make a patch for you).

	Ingo
-
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/