kern/85751: kernel panic : pppd : page fault while in kernel mode

[8084]

>Number:         85751
>Category:       kern
>Synopsis:       kernel panic : pppd : page fault while in kernel mode
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Sep 05 15:20:16 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     8084
>Release:        FreeBSD 6.0 beta1 with beta3 kernel
>Organization:
none
>Environment:
>Description:
after ctrl+C pressed it's appear:

Terminating on signal 2
read: Device not configured
Couldn't delete default route: No such process
Couldn't restore device fd flags: Device not configured
ioctl(TIOCSETD): Device not configured
.........................................
Fatal trap 12: page fault while in kernel mode

cpuid=0; apic id=00
fault virtual address=0x30
fault code = supervisor read, page not present
instruction pointer = 0x20:0xc04a51f8
stack pointer = 0x28: 0xd5750b48
frame pointer = 0x28:0xd5750ba8
code segment = base 0x0, limit 0xfffff, type 0x1b
		=DPL 0, pres 1, def 32 1, gran 1
processors eflags = interrupt enable, resume, IOPL=0
current process = 536(pppd)
[thread pid 536 tid 100082]
stopped at devfs_setattr+0x8e: movl 0x30(%ecx), %ecx
db>trace
Tracing pid 536 tid 100082 td 0xc212e780
devfs_setattr(d5750bec, c212e780, 0, d5750c2c, c1ea4660) at devfs_setattr+0x8e
VOP_SETATTR_APV(c06f7dc0, f5750bec, 68, c1bce800, 267) at VOP_SETATTR_APV+0x9e
setfmode(c212e780, c1ea4660, 2180, a02, 1) at setfmode+0xf5
fchmod( c212e780, d5750d04, 8, 422, 2) at fchmod+0xa4
syscall(36, 36, 36, 8021, 8) at sys call + 0x295
Xint0x80_syscall() at Xint0x80_syscall+01f
--- syscall(124, FreeBSD ELF32, fchmod), eip = 0x280f2da7, esp = 0xbfbfeadc, ebp=0xbfbfead8 ---

>How-To-Repeat:
      While pppd(version - 2.3.11) running, I unplug my usn modem, and pppd is still running, i press ctrl+C, and panic
>Fix:
      
>Release-Note:
>Audit-Trail:
>Unformatted: