GNU bug report logs - #11541
24.0.97; Crash when visiting file on OS X 10.7.3

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Packages: emacs, ns;

Reported by: Florian Ebeling <florian.ebeling <at> gmail.com>

Date: Tue, 22 May 2012 16:20:02 UTC

Severity: important

Merged with 11684, 11792, 11801

Found in versions 24.0.97, 24.1.50, 24.1

Done: Jan Djärv <jan.h.d <at> swipnet.se>

Bug is archived. No further changes may be made.

Full log

Message #53 received at 11541 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Chong Yidong <cyd <at> gnu.org>
Cc: florian.ebeling <at> gmail.com, 11541 <at> debbugs.gnu.org
Subject: Re: bug#11541: 24.0.97; Crash when visiting file on OS X 10.7.3
Date: Thu, 31 May 2012 18:48:51 +0300

> From: Chong Yidong <cyd <at> gnu.org>
> Date: Thu, 31 May 2012 17:31:16 +0800
> Cc: 11541 <at> debbugs.gnu.org
> 
> Florian Ebeling <florian.ebeling <at> gmail.com> writes:
> 
> > No, still the same crash location.
> 
> Hmm, then I'm pretty much stumped.

Perhaps it will help to step through the suspect code with GDB.
According to the original backtrace:

  #18 0x00000001001a1c7a in ns_findfonts (font_spec=4366993920, isMatch=0 '\0') at nsfont.m:521
  #19 0x000000010012ff32 in font_list_entities (frame=140734799761440, spec=140734799761440) at font.c:2728
  #20 0x0000000100131d5e in font_find_for_lface (f=0x7fff5fbf5130, attrs=0x7fff5fbf5130, spec=626, c=1606373680) at font.c:3197
  #21 0x000000010017863f in fontset_find_font (fontset=4327724757, c=1606373856, face=0x7fff5fbf51e0, id=1606373856, fallback=1606373856) at fontset.c:620
  #22 0x00000001001788da in fontset_font (fontset=4355892213, c=8594, face=0x7fff5fbf5230, id=1606373936) at fontset.c:736

The crash happens when fontset_font is called with its second argument
8694, which is consistent with the character being displayed, u+2199,
RIGHTWARDS ARROW.  So doing something like this:

  (gdb) break fontset_font if c == 8594
  (gdb) r -Q

then visiting the offending file should trigger the breakpoint.  Then
you can step into the functions all the way down to ns_findfonts, and
step through ns_findfonts one line at a time, including the functions
it calls.  This will allow you to see (a) whether the font_spec
argument arrives into ns_findfonts with the correct value , and if so
(b) where and why does it get clobbered.

This might be a slower way to find the culprit, but I think it is a
lot more sure to give good results.
This bug report was last modified 12 years and 255 days ago.

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