=== STAGE B: kldunload simid with unprivileged trig holding /dev/midi0.0 open ===
--- root: kldunload simid -> UNLOAD_RC=0 (reported success), then guest dead ===
simid: loaded (softc 0xfffff8011690f8f8, 120 bytes, mpu 0xfffff8008db444c0) - open+write /dev/midi*.* then sysctl hw.simid.detach=1 / kldunload
login: simid[kldunload]: mpu401_uninit() returned 6 (FAILURE - m NOT freed, midi cdev STILL LIVE)  <<< emu_midi_detach IGNORES this and returns 0
simid[kldunload]: softc kfree'd (newbus behaviour after detach()==0); mpu401/snd_midi/cdev/callout still alive

Fatal trap 12: page fault while in kernel mode
cpuid = 2; lapic id = 2
fault virtual address	= 0xffffffff82600120
fault code		= supervisor read instruction, page not present
instruction pointer	= 0x8:0xffffffff82600120
stack pointer	        = 0x10:0xfffff800897559d8
frame pointer	        = 0x10:0xfffff80089755ab0
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= Idle
current thread          = pri 12 
db> (kernel stopped in DDB; ssh dead)