kern/73830: kernel panic when raid5 member disk is removed

[jim feldman]

>Number:         73830
>Category:       kern
>Synopsis:       kernel panic when raid5 member disk is removed
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Nov 11 18:50:23 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     jim feldman
>Release:        5.3-RELEASE
>Organization:
none
>Environment:
FreeBSD greybrd.xxx.xxx.xxx 5.3-RELEASE FreeBSD 5.3-RELEASE #0: Tue Nov  9 04:04:09 MST 2004     root at greybrd.xxx.xxx.xxx:/usr/obj/usr/src/sys/GREYBRD  i386
>Description:
      physically removing a gvinum raid5 plex subdisk (to test raid 5 function) causes the system to trap 12 page fault while in kernel mode, instead of continuing on in degraded mode.

I pull one of the scsi drives, and then see a bunch of scsi msgs as the system notices the drive has gone.  I then get the following:
sub-disk down
plex degraded
g_access failed:6

trap 12
page fault while in kernel mode
cpuid=1 apic id=01
fault virtual address   =0x18c
fault code                   supervisor write, page not present
instruction pointer      =0x8:0xc043d72c
stack pointer             =0x10:cbb17bf0
code segment            =base 0x0, limit 0xfff, type 0x1b
                                =DPL0, pres1,def32,gran1
Processor flags            interupt enabled, resume,IOPL=0
current process            22(irq11:ahc1)

hw is a dual pentium pro, the scsi controller is 
ahc1: <Adaptec aic7880 Ultra SCSI adapter> port 0x8400-0x84ff mem 0xfdffd000-0xf
dffdfff irq 11 at device 15.0 on pci1


>How-To-Repeat:
      I set up a 4 disk gvinum raid set.  I pull one of the drives, and the systems crashes
>Fix:
      
>Release-Note:
>Audit-Trail:
>Unformatted: