kern/118897: Kernel Panic acquiring IP address from DHCP server on newly enabled netcard

[Manolis Kiagias]

>Number:         118897
>Category:       kern
>Synopsis:       Kernel Panic acquiring IP address from DHCP server on newly enabled netcard
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Dec 20 18:10:02 UTC 2007
>Closed-Date:
>Last-Modified:
>Originator:     Manolis Kiagias
>Release:        6.3-RC1
>Organization:
>Environment:
FreeBSD pegasus.dyndns.org 6.3-RC1-p1 FreeBSD 6.3-RC1-p1 #2: Sun Dec  2 19:48:21 EET 2007     root at pegasus.dyndns.org:/usr/obj/usr/src/sys/PEGASUS  i386

>Description:
Machine has a broadcom network card shown as bfe0.  At boot, the card is not enabled (commented out) in rc.conf 
Driver attaches normally. 
After editing rc.conf to enable the line:

ifconfig_bfe0="DHCP"

and running:

/etc/rc.d/netif restart

there is a kernel panic while getting an address from DHCP server (a linksys home router).

panic: page fault
fault virtual address = 0x104
fault code = supervisor read, page not present
instruction pointer = 0x20:0xc052417d
stack pointer = 0x28:0xe71ffbec
frame pointer = 0x28:0xe71ffbf8
code segment = base 0x0 limit 0xfffff type 0x1b
=DPL 0, pres 1, def32 1, gran 1
=resume, IOPL=0
=971 (ifconfig)
=12
>How-To-Repeat:
The symptom is repeatable every time. Use the procedure mentioned above. The symptom does not occur if you reboot after enabling the card in rc.conf. In this case the card is assigned an IP and subsequent runs of netif have no undesirable effects.
>Fix:
None that I know. Only workaround is to reboot after enabling the rc.conf entry.

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