Re: 2.6.24-rc7 lockdep warning when poweroff

From: Dave Young
Date: Mon Jan 14 2008 - 20:21:06 EST


On Tue, Jan 15, 2008 at 08:31:48AM +0800, Dave Young wrote:
> On Jan 14, 2008 6:51 PM, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote:
> >
> > > The warning that triggered (lockdep.c:700) means that one class (key)
> > > was used with more than one name.
> >
> > Right.
> >
> > > Looking at cleanup_workqueue_thread(), the lock_acquire() there works on
> > > wq->lockdep_map, and that is only initialized at one spot:
> > > __create_workqueue_key(), thus it stands to reason that that was
> > > mis-used.
> >
> > Oh ok, yes, makes sense. Maybe something is generating a workqueue with
> > a name that's passed in but the key is statically from that place. I'll
> > try to find it.
>
> I add some debug printk and found the names :
>
> block_osm/exec_osm
>
> in drivers/message/i2o
>
> maybe this helps.

Not sure right or not, the following patch fixed the problem:

diff -upr linux/include/linux/workqueue.h linux.new/include/linux/workqueue.h
--- linux/include/linux/workqueue.h 2008-01-15 08:49:08.000000000 +0800
+++ linux.new/include/linux/workqueue.h 2008-01-15 08:49:42.000000000 +0800
@@ -154,7 +154,7 @@ __create_workqueue_key(const char *name,
#ifdef CONFIG_LOCKDEP
#define __create_workqueue(name, singlethread, freezeable) \
({ \
- static struct lock_class_key __key; \
+ struct lock_class_key __key; \
\
__create_workqueue_key((name), (singlethread), \
(freezeable), &__key); \
>
> Regards
> dave
>
> >
> > johannes
> >
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