K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2017-06-25T20:06:05.379660Z
K 7
svn:log
V 633
Correctly handle small MAP_STACK requests.

If mmap(2) is called with the MAP_STACK flag and the size which is
less or equal to the initial stack mapping size plus guard,
calculation of the mapping layout created zero-sized guard.  Attempt
to create such entry failed in vm_map_insert(), causing the whole
mmap(2) call to fail.

Fix it by adjusting the initial mapping size to have space for
non-empty guard.  Reject MAP_STACK requests which are shorter or equal
to the configured guard pages size.

Reported and tested by:	Manfred Antar <null@pozo.com>
Reviewed by:	alc, markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

END