[ruby-dev:24878] String#[]= causes dumps core

次のようにすると core を吐きます。

% ./ruby -e '
a = "a" * 0x20000
b = Object.new
c = nil
class << b; self end.send(:define_method, :to_str) {
  a.freeze
  c = a[0..-1]
  "b" * 0x30000
}
a[0..-1] = b
p c
'
-e:11: [BUG] Segmentation fault
ruby 1.9.0 (2004-11-16) [i686-linux]

zsh: abort (core dumped)  ./ruby -e 
% gdb ruby core 
GNU gdb 6.1-debian
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-linux"...Using host libthread_db library "/lib/libthread_db.so.1".

Core was generated by `./ruby -e 
a = "a" * 0x20000
b = Object.new
c = nil
class << b; self end.send(:'.
Program terminated with signal 6, Aborted.
Reading symbols from /lib/libdl.so.2...done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /lib/libcrypt.so.1...done.
Loaded symbols for /lib/libcrypt.so.1
Reading symbols from /lib/libm.so.6...done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
#0  0x4009e6b1 in kill () from /lib/libc.so.6
(gdb) bt
#0  0x4009e6b1 in kill () from /lib/libc.so.6
#1  0x4009e435 in raise () from /lib/libc.so.6
#2  0x4009f978 in abort () from /lib/libc.so.6
#3  0x080d53e6 in rb_bug (fmt=0x0) at error.c:214
#4  0x080b2402 in sigsegv (sig=11) at signal.c:446
#5  <signal handler called>
#6  rb_str_inspect (str=1075607216) at string.c:2594
#7  0x0806a8c1 in call_cfunc (func=0x80b9650 <rb_str_inspect>, recv=1075607216, len=1075810312, argc=0, argv=0x0)
    at eval.c:5386
#8  0x0805e807 in rb_call0 (klass=1075668916, recv=1075607216, id=3169, oid=1075607216, argc=0, argv=0x0, body=0x401d6264, 
    nosuper=0) at eval.c:5524
#9  0x0805eab8 in rb_call (klass=1075668916, recv=1075607216, mid=3169, argc=0, argv=0x0, scope=1) at eval.c:5745
#10 0x0805ee34 in rb_funcall (recv=1075607216, mid=1075607216, n=0) at ruby.h:634
#11 0x08087046 in rb_inspect (obj=1075607216) at object.c:345
#12 0x0807a9c1 in rb_p (obj=1075607216) at io.c:3744
#13 0x0807aa72 in rb_f_p (argc=1, argv=0xbffff108) at io.c:3774
#14 0x0806a8ba in call_cfunc (func=0x807aa00 <rb_f_p>, recv=1075673536, len=1075810312, argc=0, argv=0xbffff108)
    at eval.c:5383
#15 0x0805e807 in rb_call0 (klass=1075678356, recv=1075673536, id=7417, oid=1075607216, argc=1, argv=0xbffff108, 
    body=0x401cea64, nosuper=0) at eval.c:5524
#16 0x0805eab8 in rb_call (klass=1075678356, recv=1075673536, mid=7417, argc=1, argv=0xbffff108, scope=1) at eval.c:5745
#17 0x080598d8 in rb_eval (self=1075673536, n=0x401c76b0) at ruby.h:634
#18 0x08055e0d in ruby_exec_internal () at eval.c:1465
#19 0x08055e26 in ruby_exec () at eval.c:1483
#20 0x08055e70 in ruby_run () at eval.c:1500
#21 0x08053e85 in main (argc=1075607216, argv=0x401c76b0, envp=0xbffff8f4) at main.c:38
(gdb) 
-- 
[田中 哲][たなか あきら][Tanaka Akira]