amd64/93930: Page fault on `kldunload snd_driver`

[Edwin Sheldon]

>Number:         93930
>Category:       amd64
>Synopsis:       Page fault on `kldunload snd_driver`
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Feb 28 08:00:15 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Edwin Sheldon
>Release:        6.1-BETA2
>Organization:
>Environment:
FreeBSD deltron.hungsquirrel.org 6.1-BETA2 FreeBSD 6.1-BETA2 #0: Thu Feb 16 22:41:50 UTC 2006     root at bloom.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
Upon executing `kldunload snd_driver`, the system reboots.  dmesg shows a page fault when the command was executed.

tail of dmesg:
----------------------------

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x29
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xffffffff80556277
stack pointer           = 0x10:0xffffffffae55ba30
frame pointer           = 0x10:0xffffff004fedfe00
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         = 5983 (kldunload)
trap number             = 12
panic: page fault
Uptime: 6h14m46s
Cannot dump. No dump device defined.
Automatic reboot in 15 seconds - press a key on the console to abort
>How-To-Repeat:
# kldload snd_driver
# kldunload snd_driver
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: