From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Ulrich Mueller Newsgroups: gmane.emacs.bugs Subject: bug#18784: Coultdn't compile emacs-24.4 Date: Mon, 16 Mar 2015 21:04:08 +0100 Message-ID: <21767.14136.316805.481531@a1i15.kph.uni-mainz.de> References: <21763.19437.782573.339655@a1i15.kph.uni-mainz.de> <21763.21024.236293.665089@a1i15.kph.uni-mainz.de> <21766.40821.679834.521362@a1i15.kph.uni-mainz.de> <837fug29wr.fsf@gnu.org> <83sid4zthb.fsf@gnu.org> <83pp88zqgl.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1426536330 5109 80.91.229.3 (16 Mar 2015 20:05:30 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 16 Mar 2015 20:05:30 +0000 (UTC) Cc: 18784@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Mar 16 21:05:19 2015 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1YXbGF-0002zD-0m for geb-bug-gnu-emacs@m.gmane.org; Mon, 16 Mar 2015 21:05:15 +0100 Original-Received: from localhost ([::1]:51449 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YXbGE-0005fX-A7 for geb-bug-gnu-emacs@m.gmane.org; Mon, 16 Mar 2015 16:05:14 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:46794) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YXbG7-0005di-UN for bug-gnu-emacs@gnu.org; Mon, 16 Mar 2015 16:05:12 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YXbG2-0003Xz-CA for bug-gnu-emacs@gnu.org; Mon, 16 Mar 2015 16:05:07 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:50362) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YXbG2-0003XT-9e for bug-gnu-emacs@gnu.org; Mon, 16 Mar 2015 16:05:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1YXbG1-00080w-Nu for bug-gnu-emacs@gnu.org; Mon, 16 Mar 2015 16:05:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Ulrich Mueller Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 16 Mar 2015 20:05:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 18784 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 18784-submit@debbugs.gnu.org id=B18784.142653625330742 (code B ref 18784); Mon, 16 Mar 2015 20:05:01 +0000 Original-Received: (at 18784) by debbugs.gnu.org; 16 Mar 2015 20:04:13 +0000 Original-Received: from localhost ([127.0.0.1]:48930 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1YXbFF-0007zm-57 for submit@debbugs.gnu.org; Mon, 16 Mar 2015 16:04:13 -0400 Original-Received: from a1www.kph.uni-mainz.de ([134.93.134.1]:40083) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1YXbFC-0007zc-QF for 18784@debbugs.gnu.org; Mon, 16 Mar 2015 16:04:11 -0400 Original-Received: from a1i15.kph.uni-mainz.de (a1i15.kph.uni-mainz.de [134.93.134.92]) by a1www.kph.uni-mainz.de (8.14.9/8.14.7) with ESMTP id t2GK491M030029; Mon, 16 Mar 2015 21:04:09 +0100 Original-Received: from a1i15.kph.uni-mainz.de (localhost [127.0.0.1]) by a1i15.kph.uni-mainz.de (8.14.8/8.14.2) with ESMTP id t2GK494k015584; Mon, 16 Mar 2015 21:04:09 +0100 Original-Received: (from ulm@localhost) by a1i15.kph.uni-mainz.de (8.14.8/8.14.8/Submit) id t2GK48Xe015579; Mon, 16 Mar 2015 21:04:08 +0100 In-Reply-To: <83pp88zqgl.fsf@gnu.org> X-Mailer: VM 8.2.0b under 24.3.1 (x86_64-pc-linux-gnu) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:100560 Archived-At: >>>>> On Mon, 16 Mar 2015, Eli Zaretskii wrote: >> I guess if PIE is used in order to place Emacs's code at randomized >> addresses (different address every time an Emacs process is launched), >> it can break the dump because our subr objects will end up with pointers >> to addresses that aren't valid any more (might be other such problems, >> but that's the first that comes to my mind). > Then this is only an issue on systems where PIE == address > randomization, isn't it? That would be my guess too. Here are some gdb backtraces showing that the problem occurs in unexelf.c: https://bugs.gentoo.org/494316#c13 https://bugs.gentoo.org/526948#c9 http://debbugs.gnu.org/13847#5 There is a long history of Emacs catching up with kernel hardening in this area. It started with setting ADDR_NO_RANDOMIZE via Linux personality(2), then setting the NORANDEXEC flag with paxctl(1) or setfattr(1). Now it seems that we need -nopie in addition. My impression is that these are all workarounds that don't address the real issue.