Re: EXC_BAD_ACCESS on Mac

["Kazu Yamamoto" <kazu@iij.ad.jp>]

Hi,

Sorry for the delay. Since I terminated the previous GDB session, I
have been waiting for another catch. I had a similar catch today.

>> Program received signal EXC_BAD_ACCESS, Could not access memory.
>> Reason: 13 at address: 0x0000000000000000
>> 0x00000001002c1f0c in font_has_char (f=0x1070261b8, font=4417553805, c=38761) at font.c:2938
>> 2938	      int result = fontp->driver->has_char (font, c);
>> (gdb) info stack
> 
> Please show for frame #0 the values of the following variables:
> 
>   fontp
>   fontp->driver
>   fontp->driver->has_char

Here:

(gdb) p fontp
$1 = (struct font *) 0x10f022d90
(gdb) p fontp->driver
$2 = (struct font_driver *) 0x10200303a
(gdb) p fontp->driver->has_char
$3 = (int (*)(Lisp_Object, int)) 0x88000000000000
 
> Also, the value of the character C that was passed to font_has_char is
> 38761 or 0x9769 in hex.  This is the codepoint of the character 革.
> Is it reasonable to expect such a character to come up in the context
> of whatever you were reading/editing at the time of the crash?  Or is
> the character codepoint also suspect as garbled?

The stack trace is attached. 21843 is a part of my friend name. So, yes,
this character was preparing in a buffer.

--Kazu

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: 13 at address: 0x0000000000000000
0x00000001002c351c in font_has_char (f=0x1146bc250, font=4546768277, c=21843) at font.c:2938
2938	      int result = fontp->driver->has_char (font, c);
(gdb) 
(gdb) 
(gdb) info stack
#0  0x00000001002c351c in font_has_char (f=0x1146bc250, font=4546768277, c=21843) at font.c:2938
#1  0x000000010038437e in fontset_find_font (fontset=4545376853, c=21843, face=0x11db9caa0, id=-1, fallback=false) at fontset.c:665
#2  0x0000000100384ade in fontset_font (fontset=4545319509, c=21843, face=0x11db9caa0, id=-1) at fontset.c:759
#3  0x000000010038534e in face_for_char (f=0x1146bc250, face=0x11db9caa0, c=21843, pos=48937, object=4328534074) at fontset.c:971
#4  0x0000000100048907 in get_next_display_element (it=0x7fff5fbf9db8) at xdisp.c:6956
#5  0x0000000100070aa5 in display_line (it=0x7fff5fbf9db8) at xdisp.c:19350
#6  0x0000000100066066 in try_window (window=4565958773, pos={charpos = 48618, bytepos = 51352}, flags=1) at xdisp.c:16202
#7  0x0000000100063b44 in redisplay_window (window=4565958773, just_this_one_p=0) at xdisp.c:15732
#8  0x000000010005c444 in redisplay_window_0 (window=4565958773) at xdisp.c:13772
#9  0x0000000100294e0e in internal_condition_case_1 (bfun=0x10005c400 <redisplay_window_0>, arg=4565958773, handlers=4328545366, hfun=0x10005c3b0 <redisplay_window_error>) at eval.c:1326
#10 0x000000010005c387 in redisplay_windows (window=4565958773) at xdisp.c:13752
#11 0x000000010005c328 in redisplay_windows (window=4546907541) at xdisp.c:13746
#12 0x000000010005b22a in redisplay_internal () at xdisp.c:13363
#13 0x0000000100058a99 in redisplay () at xdisp.c:12652
#14 0x0000000100170c23 in read_char (commandflag=1, map=4563621638, prev_event=4328534074, used_mouse_menu=0x7fff5fbfeda7, end_time=0x0) at keyboard.c:2568
#15 0x0000000100180355 in read_key_sequence (keybuf=0x7fff5fbff010, bufsize=30, prompt=4328534074, dont_downcase_last=false, can_return_switch_frame=true, fix_current_buffer=true) at keyboard.c:9079
#16 0x000000010016d667 in command_loop_1 () at keyboard.c:1449
#17 0x0000000100294c93 in internal_condition_case (bfun=0x10016d140 <command_loop_1>, handlers=4328609434, hfun=0x10016c6a0 <cmd_error>) at eval.c:1289
#18 0x000000010016cc9f in command_loop_2 (ignore=4328534074) at keyboard.c:1164
#19 0x000000010029457c in internal_catch (tag=4328605578, func=0x10016cc70 <command_loop_2>, arg=4328534074) at eval.c:1063
#20 0x000000010016cc22 in command_loop () at keyboard.c:1143
#21 0x000000010016c0a3 in recursive_edit_1 () at keyboard.c:776
#22 0x000000010016c2a8 in Frecursive_edit () at keyboard.c:840
#23 0x0000000100164f7a in main (argc=1, argv=0x7fff5fbff928) at emacs.c:1550