=== FIXED kernel/module: cat the forged-busycnt=255 file ===
CAT_RC=1
--- head of output (200 bytes) ---
cat: /mnt/FILE: Invalid argument

--- wc -c ---
      33 /tmp/out
--- dmesg tail (look for forged ab_busycnt rejection) ---
hpfs_hpbmap: forged ab_busycnt 255 > max 8
--- guest still up check ---
DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64
DONE