-mm: xfs lockdep warning

[Christoph Hellwig]

On Tue, Oct 05, 2010 at 08:09:58PM +0200, Torsten Kaiser wrote:
> Here is the complete log from bootup until the hang happened the second time.
> I just logged into KDE and then started the upgrade of KOffice, which
> meant that the package manager started to compile 4 programs each with
> -j5. After a few minutes the load got to ~18 and probably at the point
> where filecache and GCCs filled up my 4GB RAM the system got stuck.
> The mouse so longer moved and SysRq+S did not work. The log was
> captured via serial console on a second system.
> 
> I will try tomorrow with frame pointers enabled..

Lots of hangs in sync_page and dm-crypt in the stack is unfortunately
something we've seen quite a few times, and it usually points to that
layer.  In the best case we might just have a similar workqueue priority
issue somewhere in the dm-crypt or maybe just md code.