# wchan proof during the first hang (pre-reset guest, pid 872 = guard_probe child in CONS_SET):
#   PID STAT   WCHAN    COMMAND
#   872 I1     scrsav   /tmp/guard_probe
# post-kill wedge (second hang, pid 932 = 'vidcontrol -p' reaching a saver-stop wait):
#   932 I1     scrsav   vidcontrol -p
# 'scrsav' is the tsleep channel string of wait_scrn_saver_stop() only (syscons.c:2727/2734).
#
# /dev/kmem statics while wedged (kread.c):
scrn_blanked     = 1          <- STUCK (never returns to 0)
scrn_blank_time  = 0
saver_mode       = 0 (CONS_LKM_SAVER)
current_saver    = 0x80b8afe0 (non-NULL, scsplash_saver)
# sc_softc flags via scread.c (sc_console->sc at 0xffffffff81b25700):
sc->flags = 0x100030040
  SC_SCRN_BLANKED(0x40) SET   <- stuck
  SC_SCRN_IDLE(0x20)   clear
  SC_SAVER_FAILED(0x80) clear
sc->cur_scp == sc_console (ttyv0 active)
# kldunload snake_saver while wedged: hangs (timeout RC=124); module permanently EBUSY.