bitkeeper revision 1.1748.1.1 (42bbd1c5CE48yPys_hWh-39fCz3QGw)

bitkeeper revision 1.1748.1.1 (42bbd1c5CE48yPys_hWh-39fCz3QGw)

Patch below is needed to make my system work stable in PAE mode.
Havn't seen problems without PAE, not sure whenever thats just
pure luck or whenever there is a bug in my PAE xenlinux kernel.
To me it looks like a generic bug though.

I've actually trapped into problems with unpin only:  A process
exits, somewhere in exit_mm() the page tables are unpinned,
shortly thereafter the mappings are cleared.  While doing so the
kernel oopses in zap_pte_range(), on page table write access.
Probably due to some stale tlb entry where the page is still
tagged read-only.