GC bug

[Alex Schroeder]

In GNU Emacs 21.3.50.1 (i686-pc-linux-gnu, X toolkit)
 of 2003-06-10 on confusibombus
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.ISO-8859-1
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t


My mysterious crashes continue -- usually when I am using Gnus, doing
IRC, and coding Perl, for quite some time.  I recently noticed that
it happens particularly often when I load pictures into Emacs, or
when I paste from Emacs to another application using X:

1. Press button 1 and mark a region.
2. Go to another application such as Mozilla Firebird 0.6
3. Copy using button 2.

Emacs will crash in the background.
Here is such a backtrace:

Program received signal SIGABRT, Aborted.
0x40248a51 in kill () from /lib/libc.so.6
(gdb) bt
#0  0x40248a51 in kill () from /lib/libc.so.6
#1  0x080d5b1a in abort () at emacs.c:417
#2  0x0811d245 in mark_object (argptr=0xbfff9d78) at alloc.c:4862
#3  0x0811bc1d in mark_memory (start=0xbfff9db0, end=0xbffff9c4) at alloc.c:3453
#4  0x0811c082 in mark_stack () at alloc.c:3835
#5  0x0811c655 in Fgarbage_collect () at alloc.c:4207
#6  0x081568c5 in Fbyte_code (bytestr=941238400, vector=1209674220, maxdepth=7) 
at bytecode.c:543
#7  0x0812fc61 in funcall_lambda (fun=1209673824, nargs=1, 
arg_vector=0xbfff9fe8) at eval.c:2911
#8  0x0812f821 in Ffuncall (nargs=2, args=0xbfff9fe4) at eval.c:2781
#9  0x08156abc in Fbyte_code (bytestr=941238400, vector=1209674220, maxdepth=7) 
at bytecode.c:710
#10 0x0812fc61 in funcall_lambda (fun=1209673824, nargs=1, 
arg_vector=0xbfffa0f8) at eval.c:2911
#11 0x0812f821 in Ffuncall (nargs=2, args=0xbfffa0f4) at eval.c:2781
#12 0x08156abc in Fbyte_code (bytestr=941238400, vector=1209674220, maxdepth=7) 
at bytecode.c:710
#13 0x0812fc61 in funcall_lambda (fun=1209673824, nargs=1, 
arg_vector=0xbfffa208) at eval.c:2911
#14 0x0812f821 in Ffuncall (nargs=2, args=0xbfffa204) at eval.c:2781
#15 0x08156abc in Fbyte_code (bytestr=941238148, vector=1209673628, maxdepth=2) 
at bytecode.c:710
#16 0x0812fc61 in funcall_lambda (fun=1209673568, nargs=1, 
arg_vector=0xbfffa378) at eval.c:2911
#17 0x0812f821 in Ffuncall (nargs=2, args=0xbfffa374) at eval.c:2781
#18 0x0812f13b in Fapply (nargs=2, args=0xbfffa374) at eval.c:2231
#19 0x0812f441 in apply1 (fn=1209673568, arg=1483759156) at eval.c:2487
#20 0x0812eeda in Feval (form=1483763556) at eval.c:2134
#21 0x0812ed32 in Feval (form=1483759708) at eval.c:2063
#22 0x0812c954 in Fprogn (args=1483763164) at eval.c:408

(gdb) up
#1  0x080d5b1a in abort () at emacs.c:417
417       kill (getpid (), SIGABRT);
(gdb) up
#2  0x0811d245 in mark_object (argptr=0xbfff9d78) at alloc.c:4862
4862              abort ();
(gdb) l
4857                  }
4858              }
4859              break;
4860    
4861            default:
4862              abort ();
4863            }
4864          break;
4865    
4866        case Lisp_Cons:
(gdb) p obj
$1 = 152079892
(gdb) xtype obj
Lisp_Int
0

Strange.

152079892 is 2#1001000100001000111000010100 according to calc.


I stared at alloc.c for about half an hour, but I really don't
understand much about GC, marking, bits, etc.