bug#23522: 25.0.93; SEGFAULT when displaying HELLO

[Michael Welsh Duggan <mwd@md5i.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Michael Welsh Duggan <mwd@cert.org>
>> Cc: <rgm@gnu.org>, <23522@debbugs.gnu.org>
>> Date: Thu, 12 May 2016 15:58:43 -0400
>> 
>> (gdb) up
>> #4  0x00000000006b47e2 in ftfont_shape_by_flt (lgstring=14496901, 
>>     font=0x17b3660, ft_face=0x1739f10, otf=0x16df8d0, matrix=0x17b3758)
>>     at ../../../git/emacs/src/ftfont.c:2655
>> (gdb) pp lgstring
>> [[#<font-object "-unknown-Lohit
>> Gujarati-normal-normal-normal-*-13-*-*-*-*-0-iso10646-1"> 2744 2765
>> 2724 2759] nil [0 0 2744 98 10 0 9 8 0 nil] [1 1 2765 115 0 -4 3 0 4
>> nil] [2 2 2724 81 9 0 8 8 0 nil] [3 3 2759 110 0 -7 -1 12 -7 nil]
>> nil nil nil nil]
>> (gdb) 
>
> In the above stack frame, what is the value of g->g (it's a
> structure)?

(gdb) p g->g
$3 = {
  c = 0, 
  code = 175, 
  from = 0, 
  to = 115, 
  xadv = 448, 
  yadv = 0, 
  ascent = 512, 
  descent = 0, 
  lbearing = 0, 
  rbearing = 448, 
  xoff = 0, 
  yoff = 0, 
  encoded = 1, 
  measured = 1, 
  adjusted = 0, 
  internal = 0
}

> The crash seems to happen when Emacs tries to display line #10 of
> HELLO, which begins with " South Asia:".  The first word after that is
> the one that causes the crash.  Can you look at another system, where
> there's no crash, and tell which font is used for that word?

Looking at previous frames, it looks like the character is char 383:

             position: 383 of 3322 (11%), column: 16
            character: સ (displayed as સ) (codepoint 2744, #o5270, #xab8)
    preferred charset: mule-unicode-0100-24ff (Unicode characters of the range U+0100..U+24FF.)
code point in charset: 0x3978
               script: gujarati
               syntax: w 	which means: word
             category: .:Base, L:Left-to-right (strong)
             to input: type "C-x 8 RET ab8" or "C-x 8 RET GUJARATI LETTER SA"
          buffer code: #xE0 #xAA #xB8
            file code: ESC #x24 #x2C #x31 #x39 #x78 (encoded by coding system iso-2022-7bit-unix)
              display: composed to form "સ્તે" (see below)

Composed with the following character(s) "્તે" using this font:
  xft:-unknown-FreeSerif-normal-normal-normal-*-15-*-*-*-*-0-iso10646-1
by these glyphs:
  [0 3 0 10195 9 0 10 10 0 nil]
  [0 3 2724 2103 10 1 10 10 1 nil]
  [0 3 2759 2132 0 -8 -2 13 -10 [-1 0 0]]

Character code properties: customize what to show
  name: GUJARATI LETTER SA
  general-category: Lo (Letter, Other)
  decomposition: (2744) ('સ')

There are text properties here:
  charset              mule-unicode-0100-24ff

-- 
Michael Welsh Duggan
(md5i@md5i.com)