=== Fix validation: rebuild dm_target_crypt.ko with DF-1634 M_ZERO patch ===
$ cd /usr/src/sys/dev/disk/dm/crypt && make obj && make
cc -O2 -pipe -D_KERNEL ... -c dm_target_crypt.c
cc -Wl,--build-id=sha1 ... -r -o dm_target_crypt.ko dm_target_crypt.o
=== CRYPT_BUILD_RC=0 ===
-rw-r--r--  1 root  wheel  21520 Jul 18 16:05 /usr/obj/usr/src/sys/dev/disk/dm/crypt/dm_target_crypt.ko
sha256(dm_target_crypt.ko) = 766a71eeb6857831bb34a6f84535e80d7ad1c560a380cc6af63655c9b712ebda
=== MODULE LOADED + TESTED (as root for backing-device access) ===
kldload /usr/obj/usr/src/sys/dev/disk/dm/crypt/dm_target_crypt.ko  -> OK
./dm_poc 1634 -> rc=-1 errno=45 (Operation not supported)   # FIXED, no panic
dmesg: dm_target_crypt: iv_mode='BOGUS' unsupported / dm_target_crypt: ENOTSUP