From owner-freebsd-hackers@FreeBSD.ORG Wed Oct 21 15:51:13 2009 Return-Path: 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 896F7106566B for ; Wed, 21 Oct 2009 15:51:13 +0000 (UTC) (envelope-from a_best01@uni-muenster.de) Received: from zivm-exrelay3.uni-muenster.de (ZIVM-EXRELAY3.UNI-MUENSTER.DE [128.176.192.20]) by mx1.freebsd.org (Postfix) with ESMTP id 175A08FC1A for ; Wed, 21 Oct 2009 15:51:12 +0000 (UTC) X-IronPort-AV: E=Sophos;i="4.44,597,1249250400"; d="txt'?scan'208";a="16434001" Received: from zivmaildisp1.uni-muenster.de (HELO ZIVMAILUSER03.UNI-MUENSTER.DE) ([128.176.188.85]) by zivm-relay3.uni-muenster.de with ESMTP; 21 Oct 2009 17:51:11 +0200 Received: by ZIVMAILUSER03.UNI-MUENSTER.DE (Postfix, from userid 149459) id 8ADC61B0750; Wed, 21 Oct 2009 17:51:11 +0200 (CEST) Date: Wed, 21 Oct 2009 17:51:04 +0200 (CEST) From: Alexander Best Sender: Organization: Westfaelische Wilhelms-Universitaet Muenster To: Message-ID: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary=+permail-200910211551041e86ffa80000182a-a_best01+ Cc: Subject: mmap(2) with MAP_ANON honouring offset although it shouldn't X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Oct 2009 15:51:13 -0000 This is a MIME encoded multipart message. --+permail-200910211551041e86ffa80000182a-a_best01+ Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit although the mmap(2) manual states in section MAP_ANON: "The offset argument is ignored." this doesn't seem to be true. running printf("%p\n", mmap((void*)0x1000, 0x1000, PROT_NONE, MAP_ANON, -1, 0x12345678)); and printf("%p\n", mmap((void*)0x1000, 0x1000, PROT_NONE, MAP_ANON, -1, 0)); produces different outputs. i've attached a patch to solve the problem. the patch is similar to the one proposed in this PR, but should apply cleanly to CURRENT: http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/71258 cheers. alex --+permail-200910211551041e86ffa80000182a-a_best01+ Content-Type: text/plain Content-Transfer-Encoding: Base64 Content-Disposition: attachment; filename="vmmmap.c.patch.txt" LS0tIHNyYy9zeXMvdm0vdm1fbW1hcC5jCTIwMDktMTAtMjEgMDQ6MTM6MjQuMDAwMDAwMDAwICsw MjAwCisrKyBzcmMvc3lzL3ZtL3ZtX21tYXAuYwkyMDA5LTEwLTIxIDA0OjEzOjQzLjAwMDAwMDAw MCArMDIwMApAQCAtMjQ1LDE1ICsyNDUsMTggQEAKIAl9CiAKIAkvKgotCSAqIEFsaWduIHRoZSBm aWxlIHBvc2l0aW9uIHRvIGEgcGFnZSBib3VuZGFyeSwKLQkgKiBhbmQgc2F2ZSBpdHMgcGFnZSBv ZmZzZXQgY29tcG9uZW50LgorCSAqIFVubGVzcyB0aGUgTUFQX0FOT04gZmxhZyBpcyBzZXQsIGFs aWduIHRoZSBmaWxlIHBvc2l0aW9uCisJICogdG8gYSBwYWdlIGJvdW5kYXJ5IGFuZCBzYXZlIGl0 cyBwYWdlIG9mZnNldCBjb21wb25lbnQuCiAJICovCi0JcGFnZW9mZiA9IChwb3MgJiBQQUdFX01B U0spOwotCXBvcyAtPSBwYWdlb2ZmOwotCi0JLyogQWRqdXN0IHNpemUgZm9yIHJvdW5kaW5nIChv biBib3RoIGVuZHMpLiAqLwotCXNpemUgKz0gcGFnZW9mZjsJCQkvKiBsb3cgZW5kLi4uICovCi0J c2l6ZSA9ICh2bV9zaXplX3QpIHJvdW5kX3BhZ2Uoc2l6ZSk7CS8qIGhpIGVuZCAqLworCWlmIChm bGFncyAmIE1BUF9BTk9OKSB7CisJCXBhZ2VvZmYgPSBwb3MgPSAwOworCX0gZWxzZSB7CisJCXBh Z2VvZmYgPSAocG9zICYgUEFHRV9NQVNLKTsKKwkJcG9zIC09IHBhZ2VvZmY7CisJCS8qIEFkanVz dCBzaXplIGZvciByb3VuZGluZyAob24gYm90aCBlbmRzKS4gKi8KKwkJc2l6ZSArPSBwYWdlb2Zm OwkJCS8qIGxvdyBlbmQuLi4gKi8KKwkJc2l6ZSA9ICh2bV9zaXplX3QpIHJvdW5kX3BhZ2Uoc2l6 ZSk7CS8qIGhpIGVuZCAqLworCX0KIAogCS8qCiAJICogQ2hlY2sgZm9yIGlsbGVnYWwgYWRkcmVz c2VzLiAgV2F0Y2ggb3V0IGZvciBhZGRyZXNzIHdyYXAuLi4gTm90ZQpAQCAtMzAwLDcgKzMwMyw2 IEBACiAJCWhhbmRsZSA9IE5VTEw7CiAJCWhhbmRsZV90eXBlID0gT0JKVF9ERUZBVUxUOwogCQlt YXhwcm90ID0gVk1fUFJPVF9BTEw7Ci0JCXBvcyA9IDA7CiAJfSBlbHNlIHsKIAkJLyoKIAkJICog TWFwcGluZyBmaWxlLCBnZXQgZnAgZm9yIHZhbGlkYXRpb24gYW5kCg== --+permail-200910211551041e86ffa80000182a-a_best01+--