Re: 2.6.18-rc1-mm1

Ingo Molnar
2006-07-10T07:45:10Z

* Andrew Morton <akpm@osdl.org> 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