== DF-4926 fixed-module race (fix.diff applied, /usr/src build) ==
-- driver (race_unload.sh): 41 kldunload invocations --
+ kldunload nvmm
+ rc=1
+ kldunload nvmm
+ rc=1
+ kldunload nvmm
+ rc=1
+ kldunload nvmm
+ rc=1
  ...
  rc=1 (EBUSY) count: 40 / rc=0: 0
  driver done, guest alive

-- racer (unprivileged storm survived) --
DF-4926 racer: fd=3 mode=combined (uid=1002)
t= 1s cap=1052354 create=19930 destroy=19930
t=33s cap=34933578 create=664107 destroy=664107
t=34s cap=36014722 create=684051 destroy=684051

-- final unload after racer death --
kldunload nvmm -> rc=0 (clean); kldstat: nvmm gone; guest UP