The LVM label are stored on any of the first four sectors, and the
PV (physical volume) header is stored within the same sector following
the LVM label. The current implementation does not fully check the
offset of PV header, when attaching a bad formatted LVM PV the kernel
may crash due to out-of-bounds memory read.
PR: [[https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=266562|266562]]
MFC after: 2 weeks