From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Ryan Johnson Newsgroups: gmane.emacs.devel Subject: Re: 64-bit emacs crashes a lot Date: Fri, 16 Aug 2013 10:24:25 -0400 Message-ID: <520E3619.200@cs.utoronto.ca> References: <51F3151D.7040000@cs.utoronto.ca> <51F33565.1090406@cornell.edu> <51F33F52.4060405@cs.utoronto.ca> <51FB1D9E.5090102@cs.utoronto.ca> <20130802080211.GA18054@calimero.vinschen.de> <51FB9228.2020309@cornell.edu> <51FBA100.90005@cs.utoronto.ca> <51FD5462.5020400@cs.utoronto.ca> <51FFBDFF.7040501@cornell.edu> <51FFC4F2.8080909@cs.utoronto.ca> <5203D89E.6030801@cornell.edu> <5203DCCA.1010105@cs.utoronto.ca> <5205B364.8090007@cs.utoronto.ca> <52064730.50404@cornell.edu> <"52065B3C.6060104@cs.utoronto <520CCA41.3000107"@cs.utoronto.ca> <520D089A.1020806@cornell.edu> <83ioz6op5v.fsf@gnu.org> <520D4036.8010303@cs.utoronto.ca> <520D900A.8000907@cornell.edu> <834naqnh9t.fsf@gnu.org> <520E0FF8.1070709@cs.utoronto.ca> <83txipn4n4.fsf@gnu.org> <520E3510.8080101@cornell.edu> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1376664537 31722 80.91.229.3 (16 Aug 2013 14:48:57 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 16 Aug 2013 14:48:57 +0000 (UTC) Cc: Eli Zaretskii , emacs-devel@gnu.org To: Ken Brown Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Aug 16 16:48:59 2013 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 1VALKl-0002Eu-8W for ged-emacs-devel@m.gmane.org; Fri, 16 Aug 2013 16:48:59 +0200 Original-Received: from localhost ([::1]:59463 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VALKk-00061b-U0 for ged-emacs-devel@m.gmane.org; Fri, 16 Aug 2013 10:48:58 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47348) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VAKxQ-0001N2-6a for emacs-devel@gnu.org; Fri, 16 Aug 2013 10:25:00 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VAKxC-0002p5-JK for emacs-devel@gnu.org; Fri, 16 Aug 2013 10:24:52 -0400 Original-Received: from bureau85.ns.utoronto.ca ([128.100.132.185]:60365) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VAKxC-0002oj-Dc; Fri, 16 Aug 2013 10:24:38 -0400 Original-Received: from [192.168.0.106] (76-10-140-156.dsl.teksavvy.com [76.10.140.156]) (authenticated bits=0) by bureau85.ns.utoronto.ca (8.13.8/8.13.8) with ESMTP id r7GEOVNo008155 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 16 Aug 2013 10:24:32 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 In-Reply-To: <520E3510.8080101@cornell.edu> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 128.100.132.185 X-Mailman-Approved-At: Fri, 16 Aug 2013 10:48:56 -0400 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:162813 Archived-At: On 16/08/2013 10:20 AM, Ken Brown wrote: > On 8/16/2013 9:31 AM, Eli Zaretskii wrote: >>> Date: Fri, 16 Aug 2013 07:41:44 -0400 >>> From: Ryan Johnson >>> >>> On 16/08/2013 4:58 AM, Eli Zaretskii wrote: >>>> Again, please move this discussion to emacs-devel. >>> Back pointer: http://cygwin.com/ml/cygwin/2013-08/msg00273.html >>> >>>>> Date: Thu, 15 Aug 2013 22:35:54 -0400 >>>>> From: Ken Brown >>>>> >>>>> 1. Invoke 'emacs-nox -Q' in mintty. >>>>> >>>>> 2. M-x compile C-a C-k ls RET >>>>> >>>>> 3. C-x o >>>>> >>>>> 4. Hit 'g' repeatedly. >>>>> >>>>> I got it to abort with Fatal error 6 after slightly over 100 >>>>> repetitions. >>>>> >>>>> I then tried the same thing with emacs-X11 (running under X, not in >>>>> mintty). I hit 'g' 200 times without a problem. I repeated this >>>>> with >>>>> emacs-w32, again 200 times without a problem. >>>>> >>>>> So there's a bug somewhere. But if it's an emacs bug, it's >>>>> strange that >>>>> it only occurs with emacs-nox and not with either of the GUI >>>>> versions of >>>>> emacs. >>>> I suspect that buffer relocation might be the reason. Can you show a >>>> backtrace from the fatal error in an unoptimized build, with the above >>>> recipe? >>> I'll try to get one. Meanwhile, is there a quick way to disable buffer >>> relocation as a sanity test? >> >> I don't think so, but maybe it's already disabled in your build. What >> do you see on these two lines when configure finishes: >> >> Should Emacs use a relocating allocator for buffers? yes >> Should Emacs use mmap(2) for buffer allocation? no > > Should Emacs use a relocating allocator for buffers? no > Should Emacs use mmap(2) for buffer allocation? yes > >> In any case, you could configure with --enable-checking=all, it might >> catch the problem earlier. >> >>> If the optimized build still crashes reliably without it, the real >>> problem is probably something else. >> >> Maybe, but not necessarily. > > FWIW, I just tried this on the trunk, both with and without > optimization. The bug is still there in the optimized build, but I > couldn't trigger it in the unoptimized build. I've also checked that > the bug occurs only in 64-bit Cygwin, not 32-bit Cygwin. > > Here's some speculation. On 64-bit Cygwin, the space allocated to the > heap and mmap goes from 0x6:00000000 to 0x700:00000000, with the heap > starting at the bottom and mmaps allocated from the top down. (I've > added the colons for readability). Is it possible that the optimized > build takes shortcuts that are somehow incompatible with this model? > > I'm grasping at straws here, but I'm just trying to think of things > that differ between the 32-bit and 64-bit systems. I also suspect that the black magic cast by emacs and cygwin clash somehow for 64-bit builds... some assumption the one makes that the other breaks... but who knows which which assumption or which one breaks it. I also cannot get the unoptimized build to crash today; I'm not sure what was going on yesterday that made it unstable, but the unwanted reboot during the night seems to have cleared up whatever it was. Ryan