LOR: dev/sound/isa/mss.c and dev/sound/pcm/channel.c

I was trying to get core or some sort of trace for what I think are kse
related, but I get this instead.

Randomly after this during various operations, my system totally locks
up (I don't know enough, whether it's related or not).


lock order reversal
 1st 0xc40bb540 pcm0 (sound softc) _at_
/usr/src/sys/dev/sound/isa/mss.c:179
 2nd 0xc40bb180 pcm0:play:0 (pcm channel) _at_
/usr/src/sys/dev/sound/pcm/channel.c
:440
Stack backtrace:
backtrace(c03e3e7c,c40bb180,c405ced4,c03d57a5,c03d587f) at
backtrace+0x17
witness_lock(c40bb180,8,c03d587f,1b8,a) at witness_lock+0x697
_mtx_lock_flags(c40bb180,0,c03d587f,1b8,c40b9700) at
_mtx_lock_flags+0xb2
chn_intr(c405ce80,18,0,1010b400,c40bb400) at chn_intr+0x2f
mss_intr(c40b9700,0,c03deda1,216,c4091d3c) at mss_intr+0x8b
ithread_loop(c4099080,d68e0d48,c03dec52,30c,0) at ithread_loop+0x182
fork_exit(c022cc70,c4099080,d68e0d48) at fork_exit+0xc0
fork_trampoline() at fork_trampoline+0x1a
--- trap 0x1, eip = 0, esp = 0xd68e0d7c, ebp = 0 ---


--
"Optimized, readable, on time; Pick any two." 

FreeBSD 5.1-CURRENT i386 
3:17PM up 37 mins, 1 user, load averages: 0.56, 0.54, 0.46