In FreeBSD 13.0-STABLE before n245764-876ffe28796c, 12.2-STABLE before r369857, 13.0-RELEASE before p1, and 12.2-RELEASE before p7, a system call triggering a fault could cause SMAP protections to be disabled for the duration of the system call. This weakness could be combined with other kernel bugs to craft an exploit.
https://security.netapp.com/advisory/ntap-20210713-0002/
https://security.FreeBSD.org/advisories/FreeBSD-SA-21:11.smap.asc