linux-kernel - Re: [Regression] 2.6.24-git3: Major annoyance during suspend/hibernation on x86-64 (bisected)

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b647ffbd0802011444n366c1537m7fb44acf0b848941@mail.gmail.com>
Date:	Fri, 1 Feb 2008 23:44:12 +0100
From:	"Dmitry Adamushko" <dmitry.adamushko@...il.com>
To:	"Ingo Molnar" <mingo@...e.hu>
Cc:	"Peter Zijlstra" <a.p.zijlstra@...llo.nl>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"Steven Rostedt" <srostedt@...hat.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Linus Torvalds" <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [Regression] 2.6.24-git3: Major annoyance during suspend/hibernation on x86-64 (bisected)

On 01/02/2008, Dmitry Adamushko <dmitry.adamushko@...il.com> wrote:
> On 01/02/2008, Ingo Molnar <mingo@...e.hu> wrote:
> >
> > thanks - i cannot reproduce it on my usual suspend/resume testbox
> > because e1000 broke on it, and this is a pretty annoying regression.
> > We'll have to undo the hung-tasks detection feature if it's not fixed
> > quickly. (there's no point in debugging features that _add_ bugs)
>
> I can reproduce it and Peter's patch does fix it for me.
>
> e.g.
> root@...th:/sys/devices/system/cpu/cpu1# time echo 0 > online
> real    0m6.743s
> root@...th:/sys/devices/system/cpu/cpu1# time echo 0 > online
> real    0m7.770s
>
> I've observed delays from ~3 s. up to ~8 s. (out of ~20 tests) so the
> 10s. delay of msleep_interruptible() might be related but
> I'm still looking for the reason why this fix helps (and what goes
> wrong with the current code).
>

heh... it's pretty obvious indeed. What's msleep_interruptible() is
all about? :-)

"sleep waiting for signals"

so the 'watchdog' thread gets woken up

[ as a result of cpu_callback(action = CPU_DEAD) --> kthread_stop() ]

just to be immediately scheduled out again for as long as the
remaining timeout > 0.

So it should work if we substitute msleep_interruptible() with
schedule_timeout_interruptible().


-- 
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/