rcutorture: meaning of "End of test: RCU_HOTPLUG"

[Su Yue]

Hi, guys
  While running rcutorture tests with "onoff_interval", some tests
failed and results show like:

=====================================================================
[  316.354501] srcud-torture:--- End of test: RCU_HOTPLUG: nreaders=1 
nfakewriters=4 stat_interval=60 verbose=2 test_no_idle_hz=1 
shuffle_interval=3 stutter=5 irqreader=1 fq\
s_duration=0 fqs_holdoff=0 fqs_stutter=3 test_boost=1/0 
test_boost_interval=7 test_boost_duration=4 shutdown_secs=0 stall_cpu=0 
stall_cpu_holdoff=10 stall_cpu_irqsoff=0 n_ba\
rrier_cbs=0 onoff_interval=3 onoff_holdoff=0
====================================================================

I am wondering that meaning of "RCU_HOTPLUG". Is it expected because
cpu hotplug is enabled in the test? Or just represents another type of
failure?

Thanks,
Su