CURRENT unusable again, too many panics

[Martin Blapp]

Ok, the commit has been identified. After Reverting this revision, my
Box doesn't panic anymore.

With this revision in place, my box panics 100% at startup doing vi.recover 
things.

Revision 1.564 / Tue Jun 27 04:28:23
2006 UTC (3 months ago) by alc 
Branch: MAIN
Changes since 1.563: +5 -3 lines 
Diff to previous 1.563 (colored)

Correct a very old and very obscure bug: vmspace_fork() calls
pmap_copy() if the mapping is VM_INHERIT_SHARE.  Suppose the mapping 
is also wired.  vmspace_fork() clears the wiring attributes in the vm
map entry but pmap_copy() copies the PG_W attribute in the PTE.  I 
don't think this is catastrophic.  It blocks pmap_remove_pages() from
destroying the mapping and corrupts the pmap's wiring count.
This revision fixes the problem by changing pmap_copy() to clear the 
PG_W attribute.

Reviewed by: tegge@