From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Dumper issue, revisited; invalid realloc/free Date: Wed, 04 Feb 2015 21:08:00 +0200 Message-ID: <83pp9pfqb3.fsf@gnu.org> References: <20150204175709.GX23507@brightrain.aerifal.cx> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1423076901 25821 80.91.229.3 (4 Feb 2015 19:08:21 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 4 Feb 2015 19:08:21 +0000 (UTC) Cc: emacs-devel@gnu.org To: Rich Felker Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Feb 04 20:08:20 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YJ5JC-00010t-VF for ged-emacs-devel@m.gmane.org; Wed, 04 Feb 2015 20:08:19 +0100 Original-Received: from localhost ([::1]:38204 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YJ5JC-0007bu-1o for ged-emacs-devel@m.gmane.org; Wed, 04 Feb 2015 14:08:18 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:38765) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YJ5J8-0007bg-Iz for emacs-devel@gnu.org; Wed, 04 Feb 2015 14:08:15 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YJ5J3-0002fz-1A for emacs-devel@gnu.org; Wed, 04 Feb 2015 14:08:14 -0500 Original-Received: from mtaout23.012.net.il ([80.179.55.175]:57087) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YJ5J2-0002fZ-PP for emacs-devel@gnu.org; Wed, 04 Feb 2015 14:08:08 -0500 Original-Received: from conversion-daemon.a-mtaout23.012.net.il by a-mtaout23.012.net.il (HyperSendmail v2007.08) id <0NJ900G00GY8DX00@a-mtaout23.012.net.il> for emacs-devel@gnu.org; Wed, 04 Feb 2015 21:08:07 +0200 (IST) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout23.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0NJ900GFVH5J85A0@a-mtaout23.012.net.il>; Wed, 04 Feb 2015 21:08:07 +0200 (IST) In-reply-to: <20150204175709.GX23507@brightrain.aerifal.cx> X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 X-Received-From: 80.179.55.175 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:182387 Archived-At: > Date: Wed, 4 Feb 2015 12:57:09 -0500 > From: Rich Felker > > The simplest solution I can find is to make the affected free > functions (xrealloc, xfree, lisp_free, and lisp_align_free) check > whether their argument is in the range of data_start...initial_brk and > act as a nop (or in the case of xrealloc, allocate a new object > without freeing the old one) when this is the case. The check is > easily accomplished by saving initial_brk=sbrk(0) at startup (to be > lazy I did this with attribute((constructor)) but other approaches > might be preferred for an upstream fix. For xrealloc, since the old > size is not known, I simply estimate it as initial_brk-block. Copying > up to the min or this value and the new size should be safe, anyway. > > Does this sound acceptable for upstream? Yes. Several platforms (Cygwin and MinGW on MS-Windows) already do exactly that.