Hi, I agree that building ruby1.8 with gcc-4.6 instead of gcc-4.7 (4.7.0-7), with no other changes, makes the segfaults go away in the small threads testcase. But it is also okay if built using gcc-4.7 with only the -fno-optimize-sibling-calls option added. This is on kfreebsd-i386 and 4-way SMP, but clearly it has affected Linux arches too (and even other distros). Regards, -- Steven Chamberlain steven@pyro.eu.org