Date: Mon, 9 Aug 2010 10:34:51 +0200
From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: walt <w41ter@gmail.com>, linux-kernel@vger.kernel.org, tj@kernel.org,
        Suresh Siddha <suresh.b.siddha@intel.com>
Subject: Re: [BISECTED] Today's Linus.git hangs during boot: can't find the
 floppy controller
Message-ID: <20100809083451.GC2169@osiris.boeblingen.de.ibm.com>
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On Mon, Aug 09, 2010 at 10:30:53AM +0200, Heiko Carstens wrote:
> On Mon, Aug 09, 2010 at 08:37:42AM +0200, Markus Trippelsdorf wrote:
> > On Sun, Aug 08, 2010 at 01:17:53PM -0700, walt wrote:
> > > This commit produces the error:
> > > 
> > > commit 6ee0578b4daaea01c96b172c6aacca43fd9807a6
> > > Author: Suresh Siddha <suresh.b.siddha@intel.com>
> > > Date:   Fri Jul 30 14:57:37 2010 -0700
> > > 
> > >     workqueue: mark init_workqueues() as early_initcall()
> > > 
> > >     Mark init_workqueues() as early_initcall() and thus it will be initialized
> > >     before smp bringup. init_workqueues() registers for the hotcpu notifier
> > >     and thus it should cope with the processors that are brought online after
> > >     the workqueues are initialized.
> > > 
> > >     x86 smp bringup code uses workqueues and uses a workaround for the
> > >     cold boot process (as the workqueues are initialized post smp_init()).
> > >     Marking init_workqueues() as early_initcall() will pave the way for
> > >     cleaning up this code.
> > > 
> > >     Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
> > >     Signed-off-by: Tejun Heo <tj@kernel.org>
> > >     Cc: Oleg Nesterov <oleg@redhat.com>
> > >     Cc: Andrew Morton <akpm@linux-foundation.org>
> > > 
> > > 
> > > Just after the error message about the floppy controller not found, the
> > > machine hangs for two minutes and then this message:
> > > 
> > > task swapper:1 blocked for greater than 120 seconds, followed by a stack
> > > trace, and again every two minutes AFAICT.
> > > 
> > > I'm not including all the gory messages and stack traces because I'm
> > > hoping you'll know what the problem is without them. (Fingers crossed.)
> > > 
> > > BTW, I see this problem only on my dual-core machine, not the older single
> > > single processor machine, as I would expect from reading the commit message.
> > > (Both machine have properly functioning floppy drives.)
> > 
> > (Added Tejun to CC)
> > 
> > I see a similar problem here. The kernel will boot, but the system will
> > not initialize (no X11). 
> > After reverting the commit, the system starts normally and the only
> > workqueue problem left is drm related:
> 
> I would guess that both of you have CONFIG_HOTPLUG_CPU disabled and enabling
> that config option will make the problem disappear.
> From the problem description and the patch it looks like it got screwed up
> the same way I did two years ago.
> See commits a802dd0eb5fc97a50cf1abb1f788a8f6cc5db635 and
> 4403b406d4369a275d483ece6ddee0088cc0d592.

Add Suresh to cc list.
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