KASSERT(9) on FreeBSD
The text 3f228fb6e42a, as FreeBSD 4.11-RELEASE, FreeBSD 4.10-RELEASE, FreeBSD 4.9-RELEASE, FreeBSD 4.8-RELEASE, FreeBSD 4.7-RELEASE, FreeBSD 4.6.2-RELEASE, FreeBSD 4.6-RELEASE, FreeBSD 4.5-RELEASE, FreeBSD 4.4-RELEASE shipped it.
kernel expression verification macro