[dm-devel] Re: lockdep warning when nesting dm devices

[Arjan van de Ven <arjan linux intel com>]

On Mon, 2006-07-17 at 03:45 +0100, Alasdair G Kergon wrote:
> On Sat, Jul 15, 2006 at 01:17:29PM +0200, Peter Osterlund wrote:
> > # echo "0 10000 linear /dev/loop0 0" | /sbin/dmsetup create test
> > # echo "0 10000 linear /dev/mapper/test 0" | /sbin/dmsetup create test2
>  
> > I get the following warning from the lockdep validator.
> > =============================================
> > [ INFO: possible recursive locking detected ]
> > ---------------------------------------------
> 
> Well at first sight the message is simply pointing out something expected - it
> only say "INFO" after all - viz. recursive use of
> 	down_read(&md->io_lock);

is this indeed the same io_lock? Because if it is it's a serious
deadlock; rwsem's are NOT self-recursive!