[ruby-talk:142505] で可能性に気がついたのですが、いま実験してみたとこ
ろ次のようにすると core を吐きます。

# ulimit -c unlimited
# ulimit -n 2048
# ./ruby -e 'IO.select(*(0...1000).map { IO.pipe }.transpose)'
-e:1: [BUG] Segmentation fault
ruby 1.9.0 (2005-05-18) [i686-linux]

Aborted (core dumped)
# gdb ruby core
GNU gdb 6.3-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 IO.select(*(0...1000).map { IO.pipe }.transpose)'.
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  0x4009e7c1 in kill () from /lib/libc.so.6
(gdb) bt
#0  0x4009e7c1 in kill () from /lib/libc.so.6
#1  0x4009e545 in raise () from /lib/libc.so.6
#2  0x4009fa88 in abort () from /lib/libc.so.6
#3  0x080df306 in rb_bug (fmt=0x0) at error.c:214
#4  0x080bc242 in sigsegv (sig=11) at signal.c:531
#5  <signal handler called>
#6  0x00000000 in ?? ()
(gdb)  

なお、プロンプトからわかるように root 権限が必要です。
-- 
[田中 哲][たなか あきら][Tanaka Akira]