aconnect occasionally causes kernel oopses

[folkert]

[ kernel bug if repeatingly aconnect'ing midi devices ]

> Does this happen if you do reconnect of kernel sequencer client?
> You can use snd-virmidi as well as snd-dummy.
> I'm asking it because it'll simplify the test a lot, which will be
> almost self-contained.

Like this?

root at lappiemctopface:~# aplaymidi -l
 Port    Client name                      Port name
 14:0    Midi Through                     Midi Through Port-0
 20:0    Virtual Raw MIDI 1-0             VirMIDI 1-0
 21:0    Virtual Raw MIDI 1-1             VirMIDI 1-1
 22:0    Virtual Raw MIDI 1-2             VirMIDI 1-2
 23:0    Virtual Raw MIDI 1-3             VirMIDI 1-3
128:0    rtpmidi lappiemctopface          Network
128:1    rtpmidi lappiemctopface          metronoom
128:2    rtpmidi lappiemctopface          AppleMidi2IPMidiBridge
128:3    rtpmidi lappiemctopface          oensoens
130:0    FLUID Synth (11462)              Synth input port (11462:0)

and then:

root at lappiemctopface:~# cat test.sh 
while true
do
	aconnect 20:0 21:0
	aconnect -d 20:0 21:0
done

root at lappiemctopface:~# for i in `seq 0 3` ; do (./test.sh &) ; done

This hard locks-up my laptop: it doesn't even respond to capslock (led
on/off) anymore nor the ctrl+prtscr+alt+b combination.