BEFORE:
scrn_blanked    = 0 (0)
scrn_blank_time = 300 (0x12c)
run_scrn_saver  = 1 (0x1)
saver_mode      = 0 (0)
current_saver   = 2159587296 (0x80b8afe0)
[1] waiting for snake to draw (VRAM cells)...
[2] snake cells=6 (saver active, screen blanked)
[3] child: CONS_SET(80x30) while blanked...
[1] waiting for snake to draw (VRAM cells)...
[2] snake cells=6 (saver active, screen blanked)
[4] child still blocked after 10s in CONS_SET: DEADLOCK REPRODUCED (wchan 'scrsav')
[5] child SIGKILLed (tsleep is PCATCH-killable)
[6] post-kill: VRAM cells=24; sleeping 10s to give the kernel every chance to recover...
[7] after 12s: VRAM cells=24; now 'kldunload snake_saver' (expect EBUSY/hang) and ps:
UNLOAD_RC=124
   PID STAT   WCHAN    COMMAND
   839 S1     wait     sh -c ps -o pid,stat,wchan,args -p $$ 2>/dev/null | head
[8] check kernel state with /tmp/kread (scrn_blanked)
PROBE_EXIT=0
AFTER:
scrn_blanked    = 1 (0x1)
scrn_blank_time = 2 (0x2)
run_scrn_saver  = 1 (0x1)
saver_mode      = 0 (0)
current_saver   = 2159587296 (0x80b8afe0)
   821 S1     wait     sh -c cc -O2 -o /tmp/deadlock_probe /tmp/deadlock_probe.