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: bug#16901: 24.3.50; emacs_backtrace.txt Date: Sat, 01 Mar 2014 10:47:14 +0200 Message-ID: <83k3ceuwz1.fsf@gnu.org> References: <5d9f431d-d0c3-4cfa-b9e5-07cdf6718d5a@default> <83mwhbwm9j.fsf@gnu.org> <53107F45.3060502@yandex.ru> <83d2i7wbyc.fsf@gnu.org> <5310AEEE.4070005@yandex.ru> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1393663636 22817 80.91.229.3 (1 Mar 2014 08:47:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 1 Mar 2014 08:47:16 +0000 (UTC) Cc: 16901@debbugs.gnu.org, lekktu@gmail.com, emacs-devel@gnu.org To: Dmitry Antipov Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Mar 01 09:47:24 2014 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 1WJfZs-0007eA-Cj for ged-emacs-devel@m.gmane.org; Sat, 01 Mar 2014 09:47:24 +0100 Original-Received: from localhost ([::1]:54742 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WJfZs-0001Eu-2b for ged-emacs-devel@m.gmane.org; Sat, 01 Mar 2014 03:47:24 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:58926) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WJfZl-0001Ek-6n for emacs-devel@gnu.org; Sat, 01 Mar 2014 03:47:22 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WJfZf-0008N1-Sn for emacs-devel@gnu.org; Sat, 01 Mar 2014 03:47:17 -0500 Original-Received: from mtaout29.012.net.il ([80.179.55.185]:38166) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WJfZf-0008Mx-Kc for emacs-devel@gnu.org; Sat, 01 Mar 2014 03:47:11 -0500 Original-Received: from conversion-daemon.mtaout29.012.net.il by mtaout29.012.net.il (HyperSendmail v2007.08) id <0N1R00I001DRBH00@mtaout29.012.net.il> for emacs-devel@gnu.org; Sat, 01 Mar 2014 10:50:10 +0200 (IST) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by mtaout29.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0N1R00C401VM7N70@mtaout29.012.net.il>; Sat, 01 Mar 2014 10:50:10 +0200 (IST) In-reply-to: <5310AEEE.4070005@yandex.ru> X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 80.179.55.185 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:169977 Archived-At: > Date: Fri, 28 Feb 2014 19:44:46 +0400 > From: Dmitry Antipov > CC: 16901@debbugs.gnu.org, lekktu@gmail.com, > Emacs development discussions > > Now I have two crash reports to make me worry about GC. Both are > irregular and looks hard to reproduce: > > - this bug (crash in compact_small_strings, MS-Windows only (?)) > > - http://debbugs.gnu.org/cgi/bugreport.cgi?bug=16817#11 - crash > marking C stack, OSX-only (?) > > These crashes may be originated by the same bug (probably irregular > heap corruption). It's known that GC-related crashes may be caused > by freeing fonts during gc_sweep; this is > http://debbugs.gnu.org/cgi/bugreport.cgi?bug=16069, but it should > not affect MS-Windows and OSX (and hopefully I'll fix it soon). > > On GNU/Linux, valgrind makes great job in finding memory-related > errors; if there are similar tools for other platforms, it would > be nice to try. And what about using GCC and (sorry RMS) LLVM > sanitizers? This is exacerbated by the fact that Drew, who is the only one that reports such assertion violations on Windows, doesn't build his Emacs. So using temacs under valgrind-like tool is not an option in this case. I'm not aware of any tools comparable with valgrind that work on Windows with GCC-generated symbol tables. However, since Emacs on Windows uses gmalloc, perhaps Juanma could build Emacs with GC_MCHECK defined, which might catch the villain closer to the corruption locus. Last time I hit a segfault in 'free', turning on these checks in gmalloc allowed me to find the culprit in just a few minutes of debugging, which is quite impressive for this sort of bugs.