From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Fix to long-standing crashes in GC Date: 19 May 2004 18:25:34 -0400 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: References: <40A3BC23.8060000@math.ku.dk> <200405180013.i4I0Ddl15818@raven.dms.auburn.edu> NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1085005683 25760 80.91.224.253 (19 May 2004 22:28:03 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Wed, 19 May 2004 22:28:03 +0000 (UTC) Cc: Luc Teirlinck , rms@gnu.org, emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Thu May 20 00:27:52 2004 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1BQZXU-0003cO-00 for ; Thu, 20 May 2004 00:27:52 +0200 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.35 #1 (Debian)) id 1BQZXU-0002V3-00 for ; Thu, 20 May 2004 00:27:52 +0200 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.34) id 1BQZVv-00051V-0j for emacs-devel@quimby.gnus.org; Wed, 19 May 2004 18:26:15 -0400 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.34) id 1BQZVp-000515-Gr for emacs-devel@gnu.org; Wed, 19 May 2004 18:26:09 -0400 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.34) id 1BQZVJ-0004xC-D8 for emacs-devel@gnu.org; Wed, 19 May 2004 18:26:08 -0400 Original-Received: from [132.204.24.67] (helo=mercure.iro.umontreal.ca) by monty-python.gnu.org with esmtp (Exim 4.34) id 1BQZVJ-0004x3-1w; Wed, 19 May 2004 18:25:37 -0400 Original-Received: from asado.iro.umontreal.ca (asado.iro.umontreal.ca [132.204.24.84]) by mercure.iro.umontreal.ca (Postfix) with ESMTP id 33C1C21158; Wed, 19 May 2004 18:25:35 -0400 (EDT) Original-Received: by asado.iro.umontreal.ca (Postfix, from userid 20848) id 1DD428CA23; Wed, 19 May 2004 18:25:35 -0400 (EDT) Original-To: storm@cua.dk (Kim F. Storm) In-Reply-To: Original-Lines: 24 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 X-DIRO-MailScanner-Information: Please contact the ISP for more information X-DIRO-MailScanner: Found to be clean X-DIRO-MailScanner-SpamCheck: n'est pas un polluriel, SpamAssassin (score=-1.524, requis 5, autolearn=not spam, BAYES_01 -1.52) X-MailScanner-From: monnier@iro.umontreal.ca X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.4 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:23740 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:23740 > I have now found two different cases where a pointer on the stack > points to GC-managed memory (mem_find finds it), to a cons cell with a > Lisp_Misc_Free in the car and a bogus list in the cdr. I suspect there > are many more such cases. Right. And it should never happen. > I included one such list in my previous mail. Yes, I've seen it. Thank you. >> So I think w need to look further. > Looking for what? For what causes Lisp_Misc_Free cells to appear in the car of cons cells that are apparently live. I'm not sure how best to do that. Maybe we should write a GC-sanity-check routine (scan all cons blocks looking for live cells with misc free objects in them) that we could call at GC-entry and GC-exit, this way we could at least see whether the problem happens during GC or between GC. Stefan