前田です。

1.1b8でfinal.rbを使うとcore dumpするようです。
require 'sync'しているスクリプトで落ちました。

/usr/local/lib/ruby/final.rb:35: [BUG] bug in variable assignment
IOT trap/Abort (core dumped)

一応バックトレースを付けておきます。

-- 
前田 修吾

#0 0x4007e159 in __kill () #1 0x4004d41d in gsignal () #2 0x805c18a in assign (self=1074621776, lhs=0x80d4f58, val=1074616576) at eval.c:2786 #3 0x805bcfe in rb_yield_0 (val=1074616576, self=1074621776) at eval.c:2639 #4 0x805be9e in rb_yield (val=1074616576) at eval.c:2689 #5 0x805f901 in proc_call (proc=1074612996, args=1074616576) at eval.c:4551 #6 0x805ccd2 in rb_call (klass=1074752616, recv=1074612996, mid=7721, argc=1, argv=0xbfffefac, scope=0) at eval.c:3137 #7 0x8059e40 in rb_eval (self=1074751356, node=0x400d732c) at eval.c:1793 #8 0x805bdbd in rb_yield_0 (val=1074612996, self=1074751356) at eval.c:2652 #9 0x805be9e in rb_yield (val=1074612996) at eval.c:2689 #10 0x804fa1c in ary_each (ary=1074611976) at array.c:520 #11 0x805ccac in rb_call (klass=1074772616, recv=1074611976, mid=3633, argc=0, argv=0x0, scope=0) at eval.c:3134 #12 0x8059467 in rb_eval (self=1074751356, node=0x400d72f0) at eval.c:1602 #13 0x8058d6c in rb_eval (self=1074751356, node=0x400d7250) at eval.c:1414 #14 0x805bdbd in rb_yield_0 (val=1074616576, self=1074751356) at eval.c:2652 #15 0x805be9e in rb_yield (val=1074616576) at eval.c:2689 #16 0x805f901 in proc_call (proc=1074622516, args=1074616576) at eval.c:4551 #17 0x805ccd2 in rb_call (klass=1074752616, recv=1074622516, mid=7721, argc=1, argv=0x80bfeb0, scope=1) at eval.c:3137 #18 0x805d755 in rb_funcall2 (recv=1074622516, mid=7721, argc=1, argv=0x80bfeb0) at eval.c:3455 #19 0x8057df2 in rb_eval_cmd (cmd=1074622516, arg=1074610456) at eval.c:909 #20 0x8065a6a in run_final (obj=1074613496) at gc.c:981 #21 0x8065ac2 in gc_call_finalizer_at_exit () at gc.c:994 #22 0x8057b15 in ruby_run () at eval.c:816 #23 0x804ecec in main (argc=2, argv=0xbffff900, envp=0xbffff90c) at main.c:32 #24 0x804ec7e in ___crt_dummy__ ()