[ruby-dev:29547] rb_big_pow() dumps core

1.8でautobuild/chkbuildが[BUG]を報告しています。
せめてmake testくらいは確認してからコミットしてほしいと思うわけですが、
何かの理由で困難なのですか?

Program received signal EXC_BAD_ACCESS, Could not access memory.
rb_big_pow (x=3474620, y=31) at bignum.c:1623
1623                    if (!BDIGITS(z)[RBIGNUM(z)->len-1]) RBIGNUM(z)->len--;
(gdb) bt
#0  rb_big_pow (x=3474620, y=31) at bignum.c:1623
#1  0x0003d8b4 in fix_pow (x=4494972, y=65) at numeric.c:2204
#2  0x0000e4d0 in rb_call0 (klass=1986880, recv=5, id=318, oid=318, argc=1, argv=0xbfff65c0, body=0x1e4ec0, flags=0) at eval.c:5813
#3  0x0000ef9c in rb_call (klass=1986880, recv=5, mid=318, argc=1, argv=0xbfff65c0, scope=0) at eval.c:6051
#4  0x000092b0 in rb_eval (self=2001380, n=0x0) at ruby.h:673
#5  0x00008f04 in rb_eval (self=2001380, n=0x0) at eval.c:3441
#6  0x00008e90 in rb_eval (self=2001380, n=0x0) at eval.c:3440
#7  0x00009130 in rb_eval (self=2001380, n=0x0) at eval.c:3456
#8  0x00004dc8 in ruby_exec_internal () at eval.c:1607
#9  0x00004e24 in ruby_exec () at eval.c:1627
#10 0x00004e6c in ruby_run () at eval.c:1637
#11 0x00002974 in main (argc=2, argv=0xbffff724, envp=0x0) at main.c:48
#12 0x0000242c in _start (argc=2, argv=0xbffff724, envp=0xbffff730) at /SourceCache/Csu/Csu-47/crt.c:267
#13 0x8fe1a278 in __dyld__dyld_start ()
(gdb)