svn commit: r367116 - stable/12/lib/libc/sys

[Konstantin Belousov]

Author: kib
Date: Wed Oct 28 21:02:43 2020
New Revision: 367116
URL: https://svnweb.freebsd.org/changeset/base/367116

Log:
  MFC r366918:
  mmap(2): Document guard size for MAP_STACK and related EINVAL.

Modified:
  stable/12/lib/libc/sys/mmap.2
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/lib/libc/sys/mmap.2
==============================================================================
--- stable/12/lib/libc/sys/mmap.2	Wed Oct 28 21:01:00 2020	(r367115)
+++ stable/12/lib/libc/sys/mmap.2	Wed Oct 28 21:02:43 2020	(r367116)
@@ -28,7 +28,7 @@
 .\"	@(#)mmap.2	8.4 (Berkeley) 5/11/95
 .\" $FreeBSD$
 .\"
-.Dd June 22, 2017
+.Dd October 21, 2020
 .Dt MMAP 2
 .Os
 .Sh NAME
@@ -335,6 +335,8 @@ Stacks created with
 automatically grow.
 Guards prevent inadvertent use of the regions into which those
 stacks can grow without requiring mapping the whole stack in advance.
+The size of the guard, in pages, is specified by sysctl
+.Dv security.bsd.stack_guard_page .
 .El
 .Pp
 The
@@ -435,6 +437,11 @@ or
 .Dv MAP_STACK
 was specified.
 At least one of these flags must be included.
+.It Bq Er EINVAL
+.Dv MAP_STACK
+was specified and
+.Va len
+is less than or equal to the guard size.
 .It Bq Er EINVAL
 .Dv MAP_FIXED
 was specified and the