kern/89224: [sound]kernel panic after kldunload snd_maestro3

[Vladimir V. Pavluk]

>Number:         89224
>Category:       kern
>Synopsis:       [sound]kernel panic after kldunload snd_maestro3
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Nov 18 10:40:13 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Vladimir V. Pavluk
>Release:        FreeBSD 5.4-RELEASE-p8
>Organization:
Digital Service, LLC
>Environment:
FreeBSD vvp-nb.dgs.ru 5.4-RELEASE-p8 FreeBSD 5.4-RELEASE-p8 #9: Mon Nov 14 16:08:05 NOVT 2005     root at vvp-nb.dgs.ru:/usr/src/sys/i386/compile/VVP-NB  i386
>Description:
kldunload snd_maestro3 causes kernel panic. This happens only after kmix (KDE mixer program) have been ran. This is an output of dmesg after such panic:
(kldunload while kmix is running)
pcm0: unregister: mixer busy
(kldunload after exit kmix)
WARNING: Driver mistake: destroy_dev on 0/0
panic: don't do that
Uptime: 52m31s
Cannot dump. No dump device defined.
Automatic reboot in 15 seconds - press a key on the console to abort
Rebooting...

I'm running on Compaq Evo N600c.
This happens both with and without maestro3 patch [pr 89046].
>How-To-Repeat:
1) kldload snd_maestro3 (if not already loaded)
2) run kmix
3) try to kldunload snd_maestro3 (should say that device busy)
4) exit kmix
5) kldunload snd_maestro3
>Fix:
              
>Release-Note:
>Audit-Trail:
>Unformatted: