linux-kernel - Re: [patch 1/2] Ignore stolen time in the softlockup watchdog

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: <46094C02.9050702@redhat.com>
Date:	Tue, 27 Mar 2007 12:53:22 -0400
From:	Prarit Bhargava <prarit@...hat.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	virtualization@...ts.osdl.org, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	john stultz <johnstul@...ibm.com>,
	Zachary Amsden <zach@...are.com>,
	James Morris <jmorris@...ei.org>,
	Dan Hecht <dhecht@...are.com>,
	Paul Mackerras <paulus@...ba.org>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Chris Lalancette <clalance@...hat.com>,
	Rick Lindsley <ricklind@...ibm.com>
Subject: Re: [patch 1/2] Ignore stolen time in the softlockup watchdog



Jeremy Fitzhardinge wrote:
> Prarit Bhargava wrote:
>   
>> I'd like to see this patch implement/fix touch_cpu_softlockup_watchdog
>> and touch_softlockup_watchdog to mimic touch_nmi_watchdog's behaviour.
>>     
>
> Why?  Is that more correct?  It seems to me that you're interested in
> whether a specific CPU has gone and locked up.  If touching the watchdog
>   
> makes it update all CPU timestamps, then you'll hide the fact that other
> CPUs have locked up, won't it?
>
>   
In case of misuse, yes.  But there are cases where we know that all CPUs 
will have softlockup issues, such as when doing a "big" sysrq-t dump.  
When doing the sysrq-t we take the tasklist_lock which prevents all 
other CPUs from scheduling -- this leads to bogus softlockup messages, 
so we need to reset everyone's watchdog just before releasing the 
tasklist_lock.

Another question -- are you going to expose disable/enable_watchdog to 
other subsystems?  Or are you going to expose touch_softlockup_watchdog?

>     J
>   
-
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/