I just replied to the other copy of this email: Because OFED 1.1-rc2 and -rc3 inadvertently contained libibverbs code taken from the unstable unreleased libibverbs 1.1 tree. -rc4 reverted back to the stable libibverbs 1.0 code. http://openib.org/bugzilla/show_bug.cgi?id=219 has more details.