Re: 2.6.18-rc1-mm1

[Ingo Molnar]

* Andrew Morton <akpm@xxxxxxxx> wrote:

> > This looks like a problem with cpufreq.
> > 
> > =======================================================
> > [ INFO: possible circular locking dependency detected ]
> > -------------------------------------------------------
> > cpuspeed/1426 is trying to acquire lock:
> >  (&inode->i_data.tree_lock){.+..}, at: [<c0151dc7>] find_get_page+0x12/0x70
> > 
> > but task is already holding lock:
> >  (&mm->mmap_sem){----}, at: [<c0116cab>] do_page_fault+0x10d/0x4ea
> > 
> > which lock already depends on the new lock.
> > 
> 
> rofl.  You broke lockdep.

ouch! the lock identifications look quite funny :-| Never saw that 
happen before, i'm wondering what's going on. Michal, did this happen 
straight during bootup? Or did you remove/recompile/reinsert any modules 
perhaps?

> Well.  I guess it's barely conceivable that you earlier took an oops 
> while holding tree_lock, so lockdep decided that mmap_sem nests inside 
> tree_lock.

Arjan is preparing a patch to turn off lockdep when we crash. Although i 
dont see any trace of an earlier oops in the dmesg.

	Ingo
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