In article <1072014209.848651.10726.nullmailer / picachu.netlab.jp>,
  matz / ruby-lang.org (Yukihiro Matsumoto) writes:

> こちらでは再現しませんです。マシンが遅すぎるのかなあ。

とりあえず helium で再現しました。

akr@helium:~/ruby/ruby$ ./ruby -e 'h = {}
Thread.new { loop { h.delete_if {|k, s| s.length == 0 } } }
loop { h[rand] = "" }
'
-e:3: [BUG] Segmentation fault
ruby 1.8.1 (2003-12-21) [i686-linux]

Aborted (core dumped)
akr@helium:~/ruby/ruby$ gdb ruby core
GNU gdb 2002-04-01-cvs
Copyright 2002 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"...
Core was generated by `./ruby -e h = {}
Thread.new { loop { h.delete_if {|k, s| s.length == 0 } } }
lo'.
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  0x40095781 in kill () from /lib/libc.so.6
(gdb) where
#0  0x40095781 in kill () from /lib/libc.so.6
#1  0x40095464 in raise () from /lib/libc.so.6
#2  0x40096be1 in abort () from /lib/libc.so.6
#3  0x080c25fa in rb_bug () at error.c:199
#4  0x080a6dcf in sigsegv () at signal.c:419
#5  0x400956b8 in sigaction () from /lib/libc.so.6
#6  0x0806d2ec in rb_hash_aset (hash=1075482660, key=1075357140, val=1075357120) at hash.c:562
#7  0x0805b9a4 in rb_call0 (klass=1075518260, recv=1075482660, id=332, oid=332, argc=2, argv=0xbfffe7b4, body=0x401b1918, 
    nosuper=0) at eval.c:4937
#8  0x0805c3e6 in rb_call (klass=1075518260, recv=1075482660, mid=332, argc=2, argv=0xbfffe7b4, scope=0) at eval.c:5283
#9  0x08056e7f in rb_eval (self=1075546680, n=0x401a909c) at eval.c:3058
#10 0x08059d73 in rb_yield_0 (val=6, self=1075546680, klass=0, flags=0, avalue=0) at eval.c:4293
#11 0x0805a068 in rb_f_loop () at eval.c:4394
#12 0x0805b9c1 in rb_call0 (klass=1075551400, recv=1075546680, id=3929, oid=3929, argc=0, argv=0x0, body=0x401b8178, 
    nosuper=0) at eval.c:4940
#13 0x0805c3e6 in rb_call (klass=1075551400, recv=1075546680, mid=3929, argc=0, argv=0x0, scope=1) at eval.c:5283
#14 0x080572ac in rb_eval (self=1075546680, n=0x401a9074) at eval.c:3091
#15 0x0805630c in rb_eval (self=1075546680, n=0x401a9178) at eval.c:2796
#16 0x08053350 in eval_node (self=1075546680, node=0x401a9178) at eval.c:1267
#17 0x0805381e in ruby_exec () at eval.c:1436
#18 0x0805387a in ruby_run () at eval.c:1457
#19 0x08051d42 in Letext () at main.c:50
#20 0x4008514f in __libc_start_main () from /lib/libc.so.6
(gdb) 
-- 
[田中 哲][たなか あきら][Tanaka Akira]