From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Pearce Subject: Re: Segfault in xdl_merge is back Date: Wed, 27 Dec 2006 03:24:40 -0500 Message-ID: <20061227082440.GC23022@spearce.org> References: <20061227041644.GA22449@spearce.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Johannes Schindelin , Junio C Hamano , git@vger.kernel.org X-From: git-owner@vger.kernel.org Wed Dec 27 09:24:56 2006 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by dough.gmane.org with esmtp (Exim 4.50) id 1GzU5k-0003tz-Kf for gcvg-git@gmane.org; Wed, 27 Dec 2006 09:24:52 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753102AbWL0IYt (ORCPT ); Wed, 27 Dec 2006 03:24:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753545AbWL0IYt (ORCPT ); Wed, 27 Dec 2006 03:24:49 -0500 Received: from corvette.plexpod.net ([64.38.20.226]:56095 "EHLO corvette.plexpod.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752301AbWL0IYt (ORCPT ); Wed, 27 Dec 2006 03:24:49 -0500 Received: from cpe-74-70-48-173.nycap.res.rr.com ([74.70.48.173] helo=asimov.home.spearce.org) by corvette.plexpod.net with esmtpa (Exim 4.52) id 1GzU5i-0005ok-9x; Wed, 27 Dec 2006 03:24:50 -0500 Received: by asimov.home.spearce.org (Postfix, from userid 1000) id 149F420FB65; Wed, 27 Dec 2006 03:24:40 -0500 (EST) To: Linus Torvalds Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - corvette.plexpod.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - spearce.org X-Source: X-Source-Args: X-Source-Dir: Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Linus Torvalds wrote: > On Tue, 26 Dec 2006, Shawn Pearce wrote: > > > > I'm suspecting this is actually some sort of memory corruption in > > the heap (due to a bad malloc/free) as the bug seems to rear its > > head only based on the data we are allocating/have allocated. > > Can you try to reproduce it under Linux and use "valgrind" to run the > thing that SIGSEGV's? That tends to be a pretty good way to debug bad > allocations.. > > So instead of bisecting it on cygwin, try to use the build that broke on > Linux too (ie undo the 5caf9232 "fix") and when you can reproduce it under > Linux, compiel withour -O2 and with debug information, and gdb will be a > lot more useful, but also run it with valgrind.. Good advice. Unfortunately it may be difficult to get valgrind onto a Linux system where I can also put that repository which is failing. Junio suggested that I try running git-merge-file on the three blobs that I'm segfaulting on. That's a pretty quick test. Failing that I may have to find a way to get valgrind onto a Linux system - but that could take a month or more. (The UNIX admins are overworked and don't care much about Linux, and I don't have my own Linux system there.) I'd really like to get this segfault fixed before 1.5.0 ships. Its a rather nasty bug and I suspect the culprit is already in 1.5.0-rc0. -- Shawn.