From: "Chris \"ク\" Heath" <chris@...>
Date: 2008-01-09T14:51:19+09:00
Subject: Segmentation fault when calling procs

Hi,

I have noticed some random, but frequent, segmentation faults when
calling procs in ruby 1.9.

I am compiling on CentOS 4.6 Linux with gcc 3.4.6 and bison 1.875c.  I
think it may be the same issue as reported by Dirkjan Bussink here:

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/14395

but I see there are no replies to that message.

In an attempt to track this bug down, I set VMDEBUG to 1 in vm.h.  To my
surprise, ruby wouldn't even build after doing this.  The problem was
that miniruby failed a sanity check while... calling a block!  And it
seems to be 100% reproducible on my system.

I have tried both 1.9.0 (release + the patch for bison 1.8), and also
tried svn trunk.

Any ideas for how to debug this?

Here is the stderr output

[root@vmware-cheath ruby19]# make > /dev/null
/home/cheath/ruby19/lib/mkmf.rb:1310: [BUG] !!!invalid svar!!!
ruby 1.9.0 (2007-12-25 revision 0) [i686-linux]

-- control frame ----------
c:0008 p:---- s:0032 b:0032 l:000031 d:000031 CFUNC  :call
c:0007 p:0122 s:0028 b:0028 l:000be0 d:000027 BLOCK  /home/cheath/ruby19/lib/mkmf.rb:1310
c:0006 p:---- s:0028 b:0028 l:000027 d:000027 FINISH :singleton_method_added
c:0005 p:---- s:0026 b:0026 l:000025 d:000025 CFUNC  :each_line
c:0004 p:0040 s:0023 b:0023 l:000be0 d:000be0 METHOD /home/cheath/ruby19/lib/mkmf.rb:1299
c:0003 p:0247 s:0013 b:0012 l:002124 d:002124 TOP    ./enc/make_encmake.rb:21
c:0002 p:---- s:0004 b:0004 l:000003 d:000003 FINISH :inherited
c:0001 p:0000 s:0002 b:0002 l:000001 d:000001 TOP    <dummy toplevel>:17
---------------------------
DBG> : "/home/cheath/ruby19/lib/mkmf.rb:1310:in `block in depend_rules'"
DBG> : "/home/cheath/ruby19/lib/mkmf.rb:1299:in `each_line'"
DBG> : "/home/cheath/ruby19/lib/mkmf.rb:1299:in `depend_rules'"
DBG> : "./enc/make_encmake.rb:21:in `<main>'"
-- backtrace of native function call (Use addr2line) --
0x81019e8
0x806b0be
0x806b0f0
0x80f8422
0x80ff117
0x8074da0
0x80ff7f0
0x80f9fd3
0x80fe8c9
0x80fefe0
0x80ffa3b
0x806e07f
0x80daa7d
0x80ff7f0
0x80f9fd3
0x80fe8c9
0x810020a
0x806dbb9
0x8070ab4
0x805832a
0x2f8de3
0x8058255
-------------------------------------------------------
make: *** [enc.mk] Aborted