valid VMA ranges and mincore()

[Bruno Haible]

Hello Konstantin,

Thanks for reacting on this issue.

> Please, evaluate the patch. If it does what you need

- It doesn't change the manual page mincore.2.
- For unmapped areas, it appears to be filling in values of -1 into
  the array. This is not what Linux, Solaris, NetBSD do: They return
  -1 from the system call and set errno to ENOMEM. See
  Linux:    http://linux.about.com/library/cmd/blcmdl2_mincore.htm
  Solaris:  http://docs.sun.com/app/docs/doc/816-5167/6mbb2jaib?a=view
  NetBSD:   http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libc/sys/mincore.2?rev=1.19&content-type=text/plain
- Filling in values of -1 into the array will confuse existing applications,
  because -1 is all bits set, i.e. the nonexistent pages will appear to
  be in-core, modified, referenced.
- Filling in values of -1 into the array could be done more easily by
  changing the statements in sys/vm/vm_mmap.c lines 861 and 902.

Thanks.

Bruno