From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Jason Rumney Newsgroups: gmane.emacs.devel Subject: Re: [BUG] Emacs thinks it has a BDF font Date: 01 Oct 2003 08:40:11 +0100 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: References: NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1064994226 29582 80.91.224.253 (1 Oct 2003 07:43:46 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Wed, 1 Oct 2003 07:43:46 +0000 (UTC) Cc: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Wed Oct 01 09:43:44 2003 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1A4beC-0002c4-00 for ; Wed, 01 Oct 2003 09:43:44 +0200 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.35 #1 (Debian)) id 1A4beB-0001hm-00 for ; Wed, 01 Oct 2003 09:43:43 +0200 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.24) id 1A4bcJ-0001qQ-44 for emacs-devel@quimby.gnus.org; Wed, 01 Oct 2003 03:41:47 -0400 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.24) id 1A4bbt-0001kC-3d for emacs-devel@gnu.org; Wed, 01 Oct 2003 03:41:21 -0400 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.24) id 1A4bbH-0001QI-FC for emacs-devel@gnu.org; Wed, 01 Oct 2003 03:41:14 -0400 Original-Received: from [194.106.33.36] (helo=server0027.freedom2surf.net) by monty-python.gnu.org with esmtp (TLSv1:DES-CBC3-SHA:168) (Exim 4.24) id 1A4bbG-0001PC-CG for emacs-devel@gnu.org; Wed, 01 Oct 2003 03:40:42 -0400 Original-Received: from wanchan.jasonr.f2s.com ([195.137.103.251]) by server0027.freedom2surf.net (8.12.6/8.12.6/Debian-7) with ESMTP id h917eait000635; Wed, 1 Oct 2003 07:40:37 GMT Original-Received: from NYAUMO (nyaumo.jasonrumney.net [10.0.0.27]) by wanchan.jasonr.f2s.com (Postfix) with ESMTP id 39815DDDE4; Wed, 1 Oct 2003 08:39:31 +0100 (BST) Original-To: David Abrahams In-Reply-To: Original-Lines: 22 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.2 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:16819 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:16819 David Abrahams writes: > In http://article.gmane.org/gmane.emacs.devel/16583/ I reported that > emacs is following an execution path which attempts to draw a BDF font > even though none is in use, resulting in a crash deep in the drawing > machinery about once a day for me. I'm unfamiliar with this part of > Emacs' display code. Is there someone who can give me a little > guidance about what to assert, where to set a breakpoint, or something > (anything) that will help us to track this down? In a previous report, you mentioned that this occured when you were using Gnus 5.10. Does that try to use a BDF font behind your back? If not, then you are probably looking at stack or heap corruption. Since it is happening in display code variables that are exected to change frequently, it will be very difficult to track down with data breakpoints. Take a look at the structures involved, and see if there are any arrays that might overrun. assert that the length is within limits wherever they are written. See if you can work out what variables are next to the font structure on the heap or stack when the bug occurs. Add assertions to any arrays writes there too.