Issue #5851 has been updated by Vit Ondruch. Valgrind output when compiling with -O1: # Running tests: ==8685== Invalid write of size 8 ==8685== at 0x4FDA9E8: cont_restore_1 (cont.c:675) ==8685== by 0x4FDAA12: cont_restore_0 (cont.c:771) ==8685== by 0x4FDAB0E: rb_cont_call (cont.c:910) ==8685== by 0x4FB8D90: call_cfunc (vm_insnhelper.c:317) ==8685== by 0x4FB96A8: vm_call_cfunc (vm_insnhelper.c:404) ==8685== by 0x4FB9D7F: vm_call_method (vm_insnhelper.c:534) ==8685== by 0x4FBF772: vm_exec_core (insns.def:1015) ==8685== by 0x4FCCF77: vm_exec (vm.c:1220) ==8685== by 0x4FCB870: invoke_block_from_c (vm.c:624) ==8685== by 0x4FCB986: vm_yield (vm.c:654) ==8685== by 0x4FC7D93: rb_yield_0 (vm_eval.c:740) ==8685== by 0x4FC7DCD: rb_yield (vm_eval.c:750) ==8685== Address 0x7feffad00 is not stack'd, malloc'd or (recently) free'd ==8685== *** longjmp causes uninitialized stack frame ***: ./ruby terminated ---------------------------------------- Bug #5851: make check fails when compiling with GCC 4.7 - *** longjmp causes uninitialized stack frame *** https://bugs.ruby-lang.org/issues/5851 Author: Vit Ondruch Status: Open Priority: Normal Assignee: Category: Target version: ruby -v: ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-linux] I am experiencing strange test error [1] when compiling Ruby 1.9.3-p0/1.9.3-p19/2.0.0 rev 34217 with GCC 4.7 in Fedora Rawhide [2]. Everything worked just fine with GCC 4.6. Vit [1] https://gist.github.com/1564328 [2] http://koji.fedoraproject.org/koji/taskinfo?taskID=3624339 -- http://bugs.ruby-lang.org/