--- vmstat -m ath_hal BEFORE ---
(no ath_hal line — 0 in-use blocks)
--- kldload (inert) + trigger ---
KLDLOAD_OK
hw.v4kleak: 0 -> 0
--- vmstat -m ath_hal AFTER (3x200 failed attaches) ---
            ath_hal     600    675K       0    390M      800
--- kldunload ---
KLDUNLOAD_OK
--- vmstat -m ath_hal AFTER UNLOAD (must be unchanged: permanent) ---
            ath_hal     600    675K       0    390M      800