=== baseline M_BUS ===
                bus     940   97.6K       0    390M    8.25K
=== control: 100 add/delete cycles WITHOUT probe (no softc) ===
hw.df5789.leakctl: -2047 -> -2047
                bus     941   97.7K       0    390M    8.44K
=== leak: 100 add/PROBE/delete cycles (8192-byte softc leaked each) ===
hw.df5789.leak: -1 -> -1
                bus     941   97.7K       0    390M    8.74K
=== leak again x100 (cumulative) ===
hw.df5789.leak: -1 -> -1
                bus     941   97.7K       0    390M    9.03K
=== unload cleanly (no dfleak devices held) ===
ok
                bus     937   97.5K       0    390M    9.04K