From: Hugh Dickins <hugh@veritas.com>

Oleg's patch was good in that exit_mmap usually does the un-accounting; but
dup_mmap still needs its own un-accounting for the case when it has charged
for a vma, but error before it's inserted into child mm's list.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>