# ===== BASELINE: stock INVARIANTS kernel #0 (Thu Jul 2 06:02:54 UTC 2026) =====
$ sysctl net.inet.accf.unloadable=1
net.inet.accf.unloadable: 0 -> 1
$ kldload accf_http
Id Refs Address                Size Name
 4    1 0xffffffff82600000    1f000 accf_http.ko
$ ./srv2975 19001 &               # (unprivileged user attaching the filter)
LISTENING port=19001 filter=httpready
$ kldunload accf_http             # root: SUCCEEDS although the listener still
KLDUNLOAD_OK                      # holds the filter -- no refcount exists
$ ./cli 19001                     # connect -> handshake completes ->
Fatal trap 12: page fault while in kernel mode
cpuid = 0; lapic id = 0
fault virtual address	= 0x0
fault code		= supervisor read instruction, page not present
instruction pointer	= 0x8:0x0        <-- CALL through accf_callback == NULL
stack pointer	        = 0x10:0xfffff8008d1f8838
current process		= Idle           <-- netisr protocol thread
kernel: type 12 trap, code=10
[guest wedged in ddb; vm.sh status => down; full serial dump in panic.txt]