Re: 2.6.18-rc1-mm1

Arjan van de Ven
2006-07-09T21:06:29Z

On Sun, 2006-07-09 at 03:52 -0700, Andrew Morton wrote:
> On Sun, 9 Jul 2006 12:32:27 +0200
> "Michal Piotrowski" <michal.k.k.piotrowski@gmail.com> wrote:
>
> > Hi,
> >
> > On 09/07/06, Andrew Morton <akpm@osdl.org> wrote:
> > >
> > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.18-rc1/2.6.18-rc1-mm1/
> > >
> >
> > 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.
>
> 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.

I think it would be justified to disable lockdep in an oops; after all
the kernel state can't really be trusted once that happen....