Xintr_ioapic_level3 jumps to 0 during softint_disestablish

[David Young <dyoung%pobox.com@localhost>]

Xintr_ioapic_level3 tries to jump to an interrupt handler at 0 while
audio0 detaches a software interrupt handler (audiodetach calls
softint_disestablish).  I can reproduce this 100% of the time at
shutdown, if I set kern.detachall to 1, but I cannot reproduce it
otherwise.

I have just tried with kern.detachall=0, but audio(4) patched to always
detach at shutdown, and the crash is the same, so adding the audio
detachment to shutdown seems to be the critical difference, even if the
bug does not reside in audio(4).  audio0 is attached at pad0, btw.

Kernel configuration (debug.ojctech.com) at
<ftp://elmendorf.ojctech.com/users/netbsd-758e1bfc/ojctech.com> and
<ftp://elmendorf.ojctech.com/users/netbsd-758e1bfc/debug.ojctech.com>.

Console typescript with dmesg, backtraces, registers, process listing at
<ftp://elmendorf.ojctech.com/users/netbsd-da5c9f4c/softint.crash>.

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933