How is supposed to be protected the units list?

[Ed Maste]

On Fri, Mar 12, 2010 at 11:19:08AM -0800, Matthew Jacob wrote:

> That's a fair comment. There is at least one case where this additional 
> lock has helped. It probably needs rethinking a little later, but for 
> now it does seem to help people.

Right, the change is an improvement over the status quo; we were
experiencing an easily reproducible panic from this issue that is solved
by this change.  We can always change it again if a more optimal
soultion is proposed.

Thanks,
Ed