remap() the region we get from mmap() to mark the fact that we are
using all of the available slack space. Any slack space is used
to form a simple brk region, and potentially more stack space than
requested at load time.

Any searches of the vma chain may well fail looking for
stack (and especially arg) addresses if the remaping is not done.
The simplest example is /proc/<pid>/cmdline, since the args
are pretty much always at the top of the data/bss/stack region.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>