From owner-freebsd-hackers@FreeBSD.ORG  Mon Jul 13 18:44:44 2009
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id BB6C9106566B;
	Mon, 13 Jul 2009 18:44:44 +0000 (UTC) (envelope-from jhb@freebsd.org)
Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42])
	by mx1.freebsd.org (Postfix) with ESMTP id 8C2718FC23;
	Mon, 13 Jul 2009 18:44:44 +0000 (UTC) (envelope-from jhb@freebsd.org)
Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net
	[66.111.2.69])
	by cyrus.watson.org (Postfix) with ESMTPSA id 3CF9746B85;
	Mon, 13 Jul 2009 14:44:44 -0400 (EDT)
Received: from jhbbsd.hudson-trading.com (unknown [209.249.190.8])
	by bigwig.baldwin.cx (Postfix) with ESMTPA id 2AFD38A097;
	Mon, 13 Jul 2009 14:44:43 -0400 (EDT)
From: John Baldwin <jhb@freebsd.org>
To: freebsd-hackers@freebsd.org
Date: Mon, 13 Jul 2009 14:28:08 -0400
User-Agent: KMail/1.9.7
References: <permail-200907050732251e86ffa8000022a8-a_best01@message-id.uni-muenster.de>
In-Reply-To: <permail-200907050732251e86ffa8000022a8-a_best01@message-id.uni-muenster.de>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200907131428.08923.jhb@freebsd.org>
X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1
	(bigwig.baldwin.cx); Mon, 13 Jul 2009 14:44:43 -0400 (EDT)
X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx
X-Virus-Status: Clean
X-Spam-Status: No, score=-2.5 required=4.2 tests=AWL,BAYES_00,RDNS_NONE
	autolearn=no version=3.2.5
X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx
Cc: Nate Eldredge <neldredge@math.ucsd.edu>, Alan Cox <alc@freebsd.org>,
	Alexander Best <alexbestms@math.uni-muenster.de>
Subject: Re: mmap/munmap with zero length
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 13 Jul 2009 18:44:45 -0000

On Sunday 05 July 2009 3:32:25 am Alexander Best wrote:
> so mmap differs from the POSIX recommendation right. the malloc.conf option
> seems more like a workaround/hack. imo it's confusing to have mmap und munmap
> deal differently with len=0. being able to succesfully alocate memory which
> cannot be removed doesn't seem logical to me.

This should fix it:

--- //depot/user/jhb/acpipci/vm/vm_mmap.c
+++ /home/jhb/work/p4/acpipci/vm/vm_mmap.c
@@ -229,7 +229,7 @@

        fp = NULL;
        /* make sure mapping fits into numeric range etc */
-       if ((ssize_t) uap->len < 0 ||
+       if ((ssize_t) uap->len <= 0 ||
            ((flags & MAP_ANON) && uap->fd != -1))
                return (EINVAL);

-- 
John Baldwin