linux-kernel - Re: [PATCH] scheduler: fix x86 regression in native_sched

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, 07 Dec 2007 12:23:10 +0100
From:	stefano.brivio@...imi.it
To:	Nick Piggin <nickpiggin@...oo.com.au>
Cc:	Ingo Molnar <mingo@...e.hu>, Robert Love <rml@...h9.net>,
	linux-kernel@...r.kernel.org, Dave Jones <davej@...hat.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>, Michael Buesch <mb@...sch.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Len Brown <lenb@...nel.org>
Subject: Re: [PATCH] scheduler: fix x86 regression in native_sched_clock

Quoting Nick Piggin <nickpiggin@...oo.com.au>:

> On Friday 07 December 2007 19:45, Ingo Molnar wrote:
>>
>> ah, printk_clock() still uses sched_clock(), not jiffies. So it's not
>> the jiffies counter that goes back and forth, it's sched_clock() - so
>> this is a printk timestamps anomaly, not related to jiffies. I thought
>> we have fixed this bug in the printk code already: sched_clock() is a
>> 'raw' interface that should not be used directly - the proper interface
>> is cpu_clock(cpu).
>
> It's a single CPU box, so sched_clock() jumping would still be
> problematic, no?

I guess so. Definitely, it didn't look like a printk issue. Drivers  
don't read logs, usually. But they got confused anyway (it seems that  
udelay's get scaled or fail or somesuch - I can't test it right now,  
will provide more feedback in a few hours).


--
Ciao
Stefano



--
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/