I found a fairly large hole in my unsharing logic.  Pte page COW behavior
breaks down when new objects are mapped.  This patch makes sure there
aren't any COW pte pages in the range of a new mapping at mmap time.

This should fix the KDE problem.  It fixed it on the test machine I've been
using.

Dave McCracken

======================================================================
Dave McCracken          IBM Linux Base Kernel Team      1-512-838-3059
dmccr@us.ibm.com                                        T/L   678-3059