csirac@avatar:~$ ruby1.8 ~/test.rb 
SandBox.new.abc:
[1, 2, 3]
SandBox.new.xyz:
About to call the block:
[1, 2, 3]
csirac@avatar:~$ /usr/local/bin/./ruby ~/test.rb
SandBox.new.abc:
[1, 2, 3]
SandBox.new.xyz:
/home/csirac/test.rb:14: [BUG] Segmentation fault
ruby 1.9.1 (2008-12-01 revision 20438) [i686-linux]

-- control frame ----------
c:0004 p:---- s:0008 b:0008 l:000007 d:000007 FINISH
c:0003 p:0089 s:0006 b:0006 l:000005 d:000005 TOP
/home/csirac/test.rb:14
c:0002 p:---- s:0004 b:0004 l:000003 d:000003 FINISH
c:0001 p:0000 s:0002 b:0002 l:000001 d:000001 TOP    <dummy toplevel>:17
---------------------------
DBG> : "/home/csirac/test.rb:14:in `<main>'"
-- backtrace of native function call (Use addr2line) --
0x8129454
0x815728e
0x81572d8
0x80d5826
0xb7fac40c
0x811799f
0x8117e24
0x8124d55
0x81253e2
0x811e3ad
0x81226e4
0x81228cc
0x805d3af
0x805e6a6
0x805bcd0
0xb7dd3455
0x805bbd1
-------------------------------------------------------
Aborted
csirac@avatar:~$ addr2line -e /usr/local/bin/ruby 0x8129454 0x815728e
0x81572d8  0x80d5826 0xb7f8340c 0x811799f 0x8117e24 0x8124d55 0x81253e2
0x811e3ad 0x81226e4 0x81228cc 0x805d3af 0x805e6a6 0x805bcd0 0xb7daa455
0x805bbd1
/usr/local/src/ruby-1.9.1-preview2/vm_dump.c:597
/usr/local/src/ruby-1.9.1-preview2/error.c:213
/usr/local/src/ruby-1.9.1-preview2/error.c:226
/usr/local/src/ruby-1.9.1-preview2/signal.c:596
??:0
/usr/local/src/ruby-1.9.1-preview2/vm_insnhelper.c:192
/usr/local/src/ruby-1.9.1-preview2/vm_insnhelper.c:844
/usr/local/src/ruby-1.9.1-preview2/vm.c:478
/usr/local/src/ruby-1.9.1-preview2/vm_insnhelper.c:402
/usr/local/src/ruby-1.9.1-preview2/insns.def:999
/usr/local/src/ruby-1.9.1-preview2/vm.c:1042
/usr/local/src/ruby-1.9.1-preview2/vm.c:1247
/usr/local/src/ruby-1.9.1-preview2/eval.c:205
/usr/local/src/ruby-1.9.1-preview2/eval.c:233
/usr/local/src/ruby-1.9.1-preview2/main.c:37
??:0
??:0