I've seen this problem when only one of {kernel, userland} was using
UVM, and the other was using the old VM.  Are you *sure* that kernel
and userland are in sync with each other?

Chris

-- 
-----------------------------------------------------cjones@math.montana.edu
Chris Jones                                          cjones@honors.montana.edu
           Mad scientist at large                    cjones@nervana.montana.edu
"Is this going to be a stand-up programming session, sir, or another bug hunt?"