cvs commit: src/sys/amd64/amd64 pmap.c src/sys/i386/i386 pmap.c

[Alan Cox]

alc         2006-09-27 18:10:16 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_6)
    sys/amd64/amd64      pmap.c 
    sys/i386/i386        pmap.c 
  Log:
  MFC
    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.
  
  Approved by: re (mux)
  
  Revision   Changes    Path
  1.516.2.8  +4 -3      src/sys/amd64/amd64/pmap.c
  1.523.2.8  +5 -3      src/sys/i386/i386/pmap.c