[ruby-dev:31077] Conditional jump or move depends on uninitialised value(s) in StringIO.new("a").gets("\n")

valgrind 下で StringIO.new("a").gets("\n") とすると、
strio_getline で
Conditional jump or move depends on uninitialised value(s)
となります。

% valgrind ./ruby -rstringio -ve 'StringIO.new("a").gets("\n")'
==12270== Memcheck, a memory error detector.
==12270== Copyright (C) 2002-2006, and GNU GPL'd, by Julian Seward et al.
==12270== Using LibVEX rev 1658, a library for dynamic binary translation.
==12270== Copyright (C) 2004-2006, and GNU GPL'd, by OpenWorks LLP.
==12270== Using valgrind-3.2.1-Debian, a dynamic binary instrumentation framework.
==12270== Copyright (C) 2000-2006, and GNU GPL'd, by Julian Seward et al.
==12270== For more details, rerun with: -v
==12270== 
--12270-- DWARF2 CFI reader: unhandled CFI instruction 0:50
--12270-- DWARF2 CFI reader: unhandled CFI instruction 0:50
--12270-- DWARF2 CFI reader: unhandled CFI instruction 0:50
--12270-- DWARF2 CFI reader: unhandled CFI instruction 0:50
ruby 1.9.0 (2007-06-28 patchlevel 0) [i686-linux]
...
==12270== Conditional jump or move depends on uninitialised value(s)
==12270==    at 0x402892E: strio_getline (stringio.c:807)
==12270==    by 0x4028D92: strio_gets (stringio.c:872)
==12270==    by 0x80E5967: call_cfunc (insnhelper.ci:270)
==12270==    by 0x80EE1F7: vm_call_cfunc (insnhelper.ci:359)
==12270==    by 0x80EDEA2: vm_call_method (insnhelper.ci:520)
==12270==    by 0x80EA2D6: vm_eval (insns.def:1194)
==12270==    by 0x80EE33D: vm_eval_body (vm.c:1150)
==12270==    by 0x80EE97A: rb_thread_eval (vm.c:1358)
==12270==    by 0x80EFCBD: yarvcore_eval_iseq (yarvcore.c:97)
==12270==    by 0x80EFDB7: yarvcore_eval_parsed (yarvcore.c:129)
==12270==    by 0x8059C0F: ruby_exec_internal (eval.c:228)
==12270==    by 0x8059C4C: ruby_exec (eval.c:243)
==12270== 
==12270== Conditional jump or move depends on uninitialised value(s)
==12270==    at 0x4028939: strio_getline (stringio.c:807)
==12270==    by 0x4028D92: strio_gets (stringio.c:872)
==12270==    by 0x80E5967: call_cfunc (insnhelper.ci:270)
==12270==    by 0x80EE1F7: vm_call_cfunc (insnhelper.ci:359)
==12270==    by 0x80EDEA2: vm_call_method (insnhelper.ci:520)
==12270==    by 0x80EA2D6: vm_eval (insns.def:1194)
==12270==    by 0x80EE33D: vm_eval_body (vm.c:1150)
==12270==    by 0x80EE97A: rb_thread_eval (vm.c:1358)
==12270==    by 0x80EFCBD: yarvcore_eval_iseq (yarvcore.c:97)
==12270==    by 0x80EFDB7: yarvcore_eval_parsed (yarvcore.c:129)
==12270==    by 0x8059C0F: ruby_exec_internal (eval.c:228)
==12270==    by 0x8059C4C: ruby_exec (eval.c:243)
...
-- 
[田中 哲][たなか あきら][Tanaka Akira]