bug#9671: 24.0.50; Two bidi crashes

[David Reitter]

On Oct 4, 2011, at 5:42 PM, Eli Zaretskii wrote:
>  Is it
> possible to have backtraces with source line numbers? how about the
> equivalent of "bt full" in GDB?
> 
> And a test case starting from "emacs -Q" is a must in most bugs.  Only
> a few can be debugged by just staring at the sources.


First of all, this may have to do with GDB and passing Emacs environment 
variables to another Emacs instance.

This may explain why we're seeing this abort in bidi:

I am reproducing at least some type of crash in bidi_initialize() when I debug 
Emacs (24) from gdb session inside an Emacs 23 - this occurs all the time, but 
not when I start it outside of Emacs/GDB:

The abort in question happens here:

  bidi_mirror_table = uniprop_table (intern ("mirroring"));
  if (NILP (bidi_mirror_table))
    abort ();

uniprop_table returns Qnil in this situation (chartab.c:1340):

  if (! CHAR_TABLE_P (table)
      || ! UNIPROP_TABLE_P (table))
    return Qnil;

And the reason for the return here is that (! CHAR_TABLE_P (table)).

I can't show all of Vchar_code_property_alist (symbol not defined?!),
but tracing uniprop_table() shows that we're correctly looking for  
prop="mirroring", and we find val:

(gdb) xprintsym val
"uni-mirrored.el"(gdb) 

At this point, table = XCDR (val) yields:

(gdb) print table
$4 = 3484193
(gdb) xprintsym table
Cannot access memory at address 0x100000004
(gdb) xprintstr table
Attempt to extract a component of a value that is not a structure pointer.

STRINGP (table) evaluates to true, so we seem to load a file, but fail because  
(! CHAR_TABLE_P (table)).

Is it possible that it's loading the wrong file?

I've watched file system activity and found indeed an access to the 
uni-mirrored.el file coming from my Emacs 23 installation!

Is it the environment?

Within Emacs GDB, the following possibly variables are set:

EMACSDATA=/Users/dr/ae.git/nextstep/Aquamacs.app/Contents/Resources/etc
EMACSPATH=/Users/dr/ae.git/nextstep/Aquamacs.app/Contents/MacOS/bin
EMACS=t
EMACSLOADPATH=/Users/dr/ae.git/nextstep/Aquamacs.app/Contents/Resources/lisp:/Users/dr/ae.git/nextstep/Aquamacs.app/Contents/Resources/leim
INSIDE_EMACS=23.3.50.39,comint
EMACSDOC=/Users/dr/ae.git/nextstep/Aquamacs.app/Contents/Resources/etc

Does this explain what's going on?


=====

bidi-crash.txt
Description: Text document

Process:         Aquamacs [1855]
Path:            /Users/USER/*/Aquamacs.app/Contents/MacOS/Aquamacs
Identifier:      org.gnu.Aquamacs
Version:         3.xdev (3.x.1317698234)
Code Type:       X86 (Native)
Parent Process:  gdb-i386-apple-darwin [1834]

Date/Time:       2011-10-05 15:54:31.404 -0400
OS Version:      Mac OS X 10.7.1 (11B26)
Report Version:  9

Interval Since Last Report:          118216 sec
Crashes Since Last Report:           1
Per-App Interval Since Last Report:  22500 sec
Per-App Crashes Since Last Report:   1
Anonymous UUID:                      91FCF483-3023-4F2A-952D-036B2116B80B

Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000

External Modification Warnings:
Debugger attached to process.

Application Specific Information:
objc[1855]: garbage collection is OFF
abort() called

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib              0x922629c6 __pthread_kill + 10
1   libsystem_c.dylib                   0x95d46f78 pthread_kill + 106
2   libsystem_c.dylib                   0x95d37bdd abort + 167
3   org.gnu.Aquamacs                    0x0026795d ns_term_shutdown + 189 
(nsterm.m:4446)
4   org.gnu.Aquamacs                    0x000f1b83 shut_down_emacs + 307 
(emacs.c:2116)
5   org.gnu.Aquamacs                    0x000ef115 fatal_error_signal + 389 
(emacs.c:352)
6   libsystem_c.dylib                   0x95d9c59b _sigtramp + 43
7   ???                                 0xffffffff 0 + 4294967295
8   libsystem_c.dylib                   0x95d37bdd abort + 167
9   org.gnu.Aquamacs                    0x000d08cf bidi_initialize + 143 
(bidi.c:764)
10  org.gnu.Aquamacs                    0x000d0a39 bidi_init_it + 57 
(bidi.c:803)
11  org.gnu.Aquamacs                    0x000254d1 init_iterator + 4017 
(xdisp.c:2791)
12  org.gnu.Aquamacs                    0x000393c8 resize_mini_window + 680 
(xdisp.c:10024)
13  org.gnu.Aquamacs                    0x00012a5e do_switch_frame + 654 
(frame.c:831)
14  org.gnu.Aquamacs                    0x00012d14 Fselect_frame + 52 
(frame.c:881)
15  org.gnu.Aquamacs                    0x0007c630 select_frame_norecord + 64 
(window.c:2923)
16  org.gnu.Aquamacs                    0x0007c7bc 
run_window_configuration_change_hook + 348 (window.c:2953)
17  org.gnu.Aquamacs                    0x0000ef26 change_frame_size_1 + 1174 
(dispnew.c:5746)
18  org.gnu.Aquamacs                    0x0000ea7a change_frame_size + 234 
(dispnew.c:5646)
19  org.gnu.Aquamacs                    0x0000e938 do_pending_window_change + 
152 (dispnew.c:5606)
20  org.gnu.Aquamacs                    0x0001987f x_set_scroll_bar_width + 143 
(frame.c:3507)
21  org.gnu.Aquamacs                    0x00017aa9 x_set_frame_parameters + 
1561 (frame.c:2939)
22  org.gnu.Aquamacs                    0x0001afa9 x_default_parameter + 201 
(frame.c:3950)
23  org.gnu.Aquamacs                    0x0027d784 Fx_create_frame + 5364 
(nsfns.m:1280)
24  org.gnu.Aquamacs                    0x001af2ca Ffuncall + 1226 (eval.c:2974)
25  org.gnu.Aquamacs                    0x0020e1e1 exec_byte_code + 3329 
(bytecode.c:785)
26  org.gnu.Aquamacs                    0x001aff0f funcall_lambda + 1295 
(eval.c:3205)
27  org.gnu.Aquamacs                    0x001af53a Ffuncall + 1850 (eval.c:3023)
28  org.gnu.Aquamacs                    0x0020e1e1 exec_byte_code + 3329 
(bytecode.c:785)
29  org.gnu.Aquamacs                    0x001aff0f funcall_lambda + 1295 
(eval.c:3205)
30  org.gnu.Aquamacs                    0x001af53a Ffuncall + 1850 (eval.c:3023)
31  org.gnu.Aquamacs                    0x0020e1e1 exec_byte_code + 3329 
(bytecode.c:785)
32  org.gnu.Aquamacs                    0x001aff0f funcall_lambda + 1295 
(eval.c:3205)
33  org.gnu.Aquamacs                    0x001af53a Ffuncall + 1850 (eval.c:3023)
34  org.gnu.Aquamacs                    0x0020e1e1 exec_byte_code + 3329 
(bytecode.c:785)
35  org.gnu.Aquamacs                    0x001afb94 funcall_lambda + 404 
(eval.c:3139)
36  org.gnu.Aquamacs                    0x001af53a Ffuncall + 1850 (eval.c:3023)
37  org.gnu.Aquamacs                    0x0020e1e1 exec_byte_code + 3329 
(bytecode.c:785)
38  org.gnu.Aquamacs                    0x001afb94 funcall_lambda + 404 
(eval.c:3139)
39  org.gnu.Aquamacs                    0x001af915 apply_lambda + 453 
(eval.c:3082)
40  org.gnu.Aquamacs                    0x001ad98d eval_sub + 2717 (eval.c:2367)
41  org.gnu.Aquamacs                    0x001acec4 Feval + 164 (eval.c:2176)
42  org.gnu.Aquamacs                    0x000f3e2c top_level_2 + 44 
(keyboard.c:1166)
43  org.gnu.Aquamacs                    0x001ab5f6 internal_condition_case + 
294 (eval.c:1499)
44  org.gnu.Aquamacs                    0x000f3e95 top_level_1 + 85 
(keyboard.c:1174)
45  org.gnu.Aquamacs                    0x001aaedf internal_catch + 223 
(eval.c:1256)
46  org.gnu.Aquamacs                    0x000f3d2b command_loop + 171 
(keyboard.c:1136)
47  org.gnu.Aquamacs                    0x000f3295 recursive_edit_1 + 181 
(keyboard.c:756)
48  org.gnu.Aquamacs                    0x000f3486 Frecursive_edit + 326 
(keyboard.c:821)
49  org.gnu.Aquamacs                    0x000f12a5 main + 6437 (emacs.c:1708)
50  org.gnu.Aquamacs                    0x00002a65 start + 53


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