SIGSEGV while reading vm mail

[Robert Mecklenburg]

This crash occurred in a freshly compiled emacs.  Please forgive my
fumbling about, I'm a newbie at emacs debugging...

I was reading mail in vm (I can't recall what command I had just
executed) when I got this:


Program received signal SIGSEGV, Segmentation fault.
Fcons (car=138601553, cdr=138493973) at alloc.c:2371
2371          cons_free_list = *(struct Lisp_Cons **)&cons_free_list->cdr;
(gdb) where
#0  Fcons (car=138601553, cdr=138493973) at alloc.c:2371
#1  0x08189394 in specbind (symbol=138601553, value=138494017) at eval.c:3025
#2  0x081b3f5e in Fbyte_code (bytestr=151252563, vector=151410284, maxdepth=56) 
at bytecode.c:651
#3  0x08188fa0 in funcall_lambda (fun=151364924, nargs=3, 
arg_vector=0xbfffdba4) at eval.c:2915
#4  0x08188a83 in Ffuncall (nargs=4, args=0xbfffdba0) at eval.c:2785
#5  0x081b40c9 in Fbyte_code (bytestr=151252659, vector=151375300, maxdepth=40) 
at bytecode.c:689
#6  0x08188fa0 in funcall_lambda (fun=150348260, nargs=3, 
arg_vector=0xbfffdd64) at eval.c:2915
#7  0x08188a83 in Ffuncall (nargs=4, args=0xbfffdd60) at eval.c:2785
#8  0x081886ee in run_hook_list_with_args (funlist=151753149, nargs=4, 
args=0xbfffdd60) at eval.c:2448
#9  0x08146ff4 in signal_after_change (charpos=79, lendel=0, lenins=2) at 
insdel.c:2146
#10 0x08145183 in insert_from_string (string=157575163, pos=0, pos_byte=0, 
length=2, length_byte=2, inherit=0)
    at insdel.c:1062
#11 0x0817f6f1 in general_insert_function (insert_func=0x8144c80 <insert>,
    insert_from_string_func=0x8145140 <insert_from_string>, inherit=0, nargs=1, 
args=0xbfffde30) at editfns.c:2031
#12 0x0817f77f in Finsert (nargs=1, args=0xbfffde30) at editfns.c:2078
#13 0x081b44a6 in Fbyte_code (bytestr=152588163, vector=152589884, maxdepth=64) 
at bytecode.c:1280
#14 0x08188fa0 in funcall_lambda (fun=152590164, nargs=1, 
arg_vector=0xbfffdf54) at eval.c:2915
#15 0x08188a83 in Ffuncall (nargs=2, args=0xbfffdf50) at eval.c:2785
#16 0x081b40c9 in Fbyte_code (bytestr=152588243, vector=152590228, maxdepth=24) 
at bytecode.c:689
#17 0x08188fa0 in funcall_lambda (fun=152590372, nargs=0, 
arg_vector=0xbfffe064) at eval.c:2915
#18 0x08188a83 in Ffuncall (nargs=1, args=0xbfffe060) at eval.c:2785
#19 0x081b40c9 in Fbyte_code (bytestr=152233691, vector=152184828, maxdepth=32) 
at bytecode.c:689
#20 0x08188fa0 in funcall_lambda (fun=152184996, nargs=1, 
arg_vector=0xbfffe194) at eval.c:2915
#21 0x08188a83 in Ffuncall (nargs=2, args=0xbfffe190) at eval.c:2785
#22 0x08188828 in call1 (fn=152184996, arg1=158380377) at eval.c:2522
#23 0x081a0f72 in map_obarray (obarray=151874156, fn=0x81a0f80 <mapatoms_1>, 
arg=152184996) at lread.c:3331
#24 0x081a0fd6 in Fmapatoms (function=152184996, obarray=151874156) at 
lread.c:3355
#25 0x08188c10 in Ffuncall (nargs=3, args=0xbfffe250) at eval.c:2739
#26 0x081b40c9 in Fbyte_code (bytestr=152233675, vector=152185060, maxdepth=24) 
at bytecode.c:689
#27 0x08188fa0 in funcall_lambda (fun=152185212, nargs=0, 
arg_vector=0xbfffe364) at eval.c:2915
#28 0x08188a83 in Ffuncall (nargs=1, args=0xbfffe360) at eval.c:2785
#29 0x081b40c9 in Fbyte_code (bytestr=152588019, vector=152589332, maxdepth=56) 
at bytecode.c:689
#30 0x08188fa0 in funcall_lambda (fun=152589596, nargs=2, 
arg_vector=0xbfffe484) at eval.c:2915
#31 0x08188a83 in Ffuncall (nargs=3, args=0xbfffe480) at eval.c:2785
#32 0x081b40c9 in Fbyte_code (bytestr=151341611, vector=140658156, maxdepth=72) 
at bytecode.c:689
#33 0x081881aa in Feval (form=141579581) at eval.c:2090
#34 0x081869ea in internal_catch (tag=138752065, func=0x8187d80 <Feval>, 
arg=141579581) at eval.c:1096
#35 0x081b38e1 in Fbyte_code (bytestr=151341579, vector=142393020, maxdepth=16) 
at bytecode.c:852
#36 0x08188fa0 in funcall_lambda (fun=151642612, nargs=3, 
arg_vector=0xbfffe7e4) at eval.c:2915
#37 0x08188a83 in Ffuncall (nargs=4, args=0xbfffe7e0) at eval.c:2785
#38 0x081b40c9 in Fbyte_code (bytestr=151503811, vector=142433364, maxdepth=32) 
at bytecode.c:689
#39 0x08188fa0 in funcall_lambda (fun=142671988, nargs=2, 
arg_vector=0xbfffe8f4) at eval.c:2915
#40 0x08188a83 in Ffuncall (nargs=3, args=0xbfffe8f0) at eval.c:2785
#41 0x081883ac in Fapply (nargs=2, args=0xbfffe970) at eval.c:2181
#42 0x081887dc in apply1 (fn=145126225, arg=153022733) at eval.c:2489
#43 0x08184375 in Fcall_interactively (function=145126225, 
record_flag=138493969, keys=138550828) at callint.c:406
#44 0x0813050e in Fcommand_execute (cmd=145126225, record_flag=138493969, 
keys=138493969, special=138493969)
    at keyboard.c:9696
#45 0x08124ba3 in command_loop_1 () at keyboard.c:1748
#46 0x08186ead in internal_condition_case (bfun=0x81247b0 <command_loop_1>, 
handlers=138554897,
    hfun=0x81242b0 <cmd_error>) at eval.c:1335
#47 0x081245db in command_loop_2 () at keyboard.c:1278
---Type <return> to continue, or q <return> to quit---
#48 0x081869ea in internal_catch (tag=138548905, func=0x81245c0 
<command_loop_2>, arg=138493969) at eval.c:1096
#49 0x08124597 in command_loop () at keyboard.c:1257
#50 0x08124002 in recursive_edit_1 () at keyboard.c:963
#51 0x0812414f in Frecursive_edit () at keyboard.c:1024
#52 0x081228ff in main (argc=3, argv=0xbffff154) at emacs.c:1687
(gdb) info locals
val = 285744787
(gdb) xgettype car
(gdb) xtype car
The history is empty.
(gdb) p car
$1 = 138601553
(gdb) xtype car
Lisp_Symbol
(gdb) p car
$2 = 138601553
(gdb) pr
buffer-undo-list
(gdb)
(gdb) p cdr
$3 = 138493973
(gdb) xtype cdr
Lisp_Cons
(gdb) p val
$4 = 285744787
(gdb) xtype
Lisp_String
(gdb) p val
$5 = 285744787
(gdb) pr

Program received signal SIGSEGV, Segmentation fault.
0x0819a324 in print_object (obj=285744787, printcharfun=138578113, 
escapeflag=1) at print.c:1502
1502              int multibyte = STRING_MULTIBYTE (obj);
The program being debugged was signaled while in a function called from GDB.
GDB remains in the frame where the signal was received.
To change this behavior use "set unwindonsignal on"
Evaluation of the expression containing the function (debug_print) will be 
abandoned.
(gdb) up
#1  0x0819814d in Fprin1 (object=285744787, printcharfun=138578113) at 
print.c:742
742       print (object, printcharfun, 1);
(gdb) up
#2  0x081994c5 in debug_print (arg=285744787) at print.c:965
965       Fprin1 (arg, Qexternal_debugging_output);
(gdb) up
#3  <function called from gdb>
Current language:  auto; currently asm
(gdb) up
#4  Fcons (car=138601553, cdr=138493973) at alloc.c:2371
2371          cons_free_list = *(struct Lisp_Cons **)&cons_free_list->cdr;
Current language:  auto; currently c
(gdb) p val
$6 = 285744787
(gdb) xstring
$7 = (struct Lisp_String *) 0x11081e90
Cannot access memory at address 0x11081e9c
(gdb) p cdr
$8 = 138493973
(gdb) xcons
$9 = (struct Lisp_Cons *) 0x8414010
{
  car = 0x971bb64,
  cdr = 0x971bb64
}
(gdb) p cdr->car
Attempt to extract a component of a value that is not a structure pointer.
(gdb) p ((Lisp_Cons *)cdr)->car
A parse error in expression, near `)cdr)->car'.
(gdb) p ((struct Lisp_Cons *)cdr)->car
$10 = 285831611
(gdb) p cdr
$11 = 138493973
(gdb) xcar
$12 = 0x971bb64
(gdb) xtype
Lisp_Vectorlike
PVEC_BUFFER
(gdb) p cdr
$13 = 138493973
(gdb) xcdr
$14 = 0x971bb64
(gdb) xtype
Lisp_Vectorlike
PVEC_BUFFER
(gdb) xvectype
PVEC_BUFFER
(gdb) xvector
$15 = (struct Lisp_Vector *) 0x971bb60
0
(gdb) p cdr
$16 = 138493973
(gdb) xcar
$17 = 0x971bb64
(gdb) xvector
$18 = (struct Lisp_Vector *) 0x971bb60
0
(gdb) p car
$19 = 138601553
(gdb) pr
buffer-undo-list
(gdb) p cdr
$20 = 138493973
(gdb) xtype
Lisp_Cons
(gdb) xcons
$21 = (struct Lisp_Cons *) 0x8414010
{
  car = 0x971bb64,
  cdr = 0x971bb64
}
(gdb) xcdr
Argument to arithmetic operation not a number or boolean.
(gdb) p cdr
$22 = 138493973
(gdb) xcdr
$23 = 0x971bb64
(gdb) xtype
Lisp_Vectorlike
PVEC_BUFFER
(gdb) xbuffer
$24 = (struct buffer *) 0x971bb60
(unsigned char *) 0x9719de4 "ecb Summary"
(gdb) p cdr
$30 = 138493973
(gdb) pr
(#<buffer ecb Summary> . #<buffer ecb Summary>)
(gdb) xbacktrace
"ad-Orig-jit-lock-after-change"
"jit-lock-after-change"
"vm-do-summary"
"vm-do-needed-summary-rebuild"
0x91228a4 PVEC_COMPILED
"mapatoms"
"vm-update-summary-and-mode-line"
"vm-summarize"
"byte-code"
"vm"
"vm-visit-folder"
"call-interactively"
(gdb) up
#5  0x08189394 in specbind (symbol=138601553, value=138494017) at eval.c:3025
3025              specpdl_ptr->symbol = Fcons (symbol, Fcons (where, 
current_buffer));
(gdb) p symbol
$31 = 138601553
(gdb) xtype
Lisp_Symbol
(gdb) pr
buffer-undo-list
(gdb) p value
$32 = 138494017
(gdb) xtype
Lisp_Symbol
(gdb) pr
t
(gdb) info locals
where = 158448484
current_buffer = 158448484
ovalue = 138494017
valcontents = Variable "valcontents" is not available.
(gdb) p where
$33 = 158448484
(gdb) xtype
Lisp_Vectorlike
PVEC_BUFFER
(gdb) xbuffer
$34 = (struct buffer *) 0x971bb60
(unsigned char *) 0x9719de4 "ecb Summary"
(gdb) p ovalue
$35 = 138494017
(gdb) xtype
Lisp_Symbol
(gdb) pr
t
(gdb) up
#6  0x081b3f5e in Fbyte_code (bytestr=151252563, vector=151410284, maxdepth=56) 
at bytecode.c:651
651               specbind (vectorp[op], POP);
(gdb) p bytestr
$36 = 151252563
(gdb) xtype
Lisp_String
(gdb) xstring
$37 = (struct Lisp_String *) 0x903ee50
"\b\205Y\000\212\306 
\031\307\216\310\211\211\211\311\211\211\032\e\034\035\036\020\036\021\036\022\016\023b\210\312
 
\026\023\313\016\023\314\"\2036\000\315\016\023\314\"\2064\000e\026\023\016\024\016\023T]d^\026\024\316\016\023\016\024\317\311$\210.\t\016\025\205X\000\016\025\016\023^\211\026\025)\207"
(gdb) p vector
$38 = 151410284
(gdb) xtype
Lisp_Vectorlike
22
(gdb) xvector
$39 = (struct Lisp_Vector *) 0x9065668
{144938289, 151251433, 138598985, 138598961, 138552113, 138635817, 138602081, 
151043909, 138494017, 138493969,
  138615129, 138669033, 144937809, 138669273, 138669321, 138693449, 138668601, 
138601769, 138601553, 138746817,
  138746793, 151250833}
(gdb) p $[0]
$42 = {
  size = 22,
  next = 0x8fd91d0,
  contents = {144938289}
}
(gdb) up
#7  0x08188fa0 in funcall_lambda (fun=151364924, nargs=3, 
arg_vector=0xbfffdba4) at eval.c:2915
2915          val = Fbyte_code (AREF (fun, COMPILED_BYTECODE),
(gdb) p fun
$47 = 151364924
(gdb) pr
#[(start end old-len) YÆ ÇÈÉ▒Ê ËÌ\"6ÍÌ\"4eT]d^ÎÏÉ$.     X^)" 
[jit-lock-mode modified buffer-file-truename buffer-file-name deactivate-mark 
inhibit-modification-hooks buffer-modified-p ((byte-codeÁÂ!Â" [modified 
restore-buffer-modified-p
Program received signal SIGSEGV, Segmentation fault.
0x0819a50a in print_object (obj=138493969, printcharfun=138578113, 
escapeflag=1) at print.c:1616
1616            if (p != end && (*p == '-' || *p == '+')) p++;
The program being debugged was signaled while in a function called from GDB.
GDB remains in the frame where the signal was received.
To change this behavior use "set unwindonsignal on"
Evaluation of the expression containing the function (debug_print) will be 
abandoned.


I ran out of steam here.  If it happens again, is there anything
special you'd like me to look at?

Thanks,
Robert





In GNU Emacs 21.3.50.11 (i686-pc-linux-gnu, GTK+ Version 2.2.4)
 of 2004-07-06 on oops.realmsys.com
configured using `configure '--with-x11' '--with-x-toolkit=gtk''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: en_US
  value of $LC_CTYPE: en_US
  value of $LC_MESSAGES: en_US
  value of $LC_MONETARY: en_US
  value of $LC_NUMERIC: en_US
  value of $LC_TIME: en_US
  value of $LANG: en_US
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Major mode: WorkLog

Minor modes in effect:
  show-paren-mode: t
  auto-image-file-mode: t
  recentf-mode: t
  auto-compression-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<down-mouse-1> <mouse-movement> <mouse-1> C-x C-s C-a 
C-n C-n C-p C-p C-p C-p C-n C-n C-n C-n C-n C-c C-g 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<menu-bar> <help-menu> <report-emacs-bug>

Recent messages:
Loading core-utils (source)...done
Loading /usr/local/share/emacs/site-lisp/local/local.el (source)...done
Loading ~/bin/emacs-helpers (source)...done
Starting the BeanShell. Please wait...
Loading semantic-el...done
Loading jit-lock...done
Mark set [2 times]
Loading mule-util...done
Wrote /home/mecklen/.worklog
Loading emacsbug...done


-- 
Robert