Panic: ffs_umount

Hi all,
I got a panic while trying to umount a floppy
I'm not a developer, but I followed the instructions in the developers
handbook, so I've got a backtrace and a dmesg attached.

The last security log before the crash had the following line:
> fd0: hard error cmd=read fsbn 62 of 56-63 (ST0 44<abnrml,top_head> ST1
20<bad_crc> ST2 20<bad_crc> cyl 1 hd 1 sec 9)


server# cd /usr/obj/usr/src/sys/server/
server# gdb -k kernel.debug /usr/local/var/crash/vmcore.0
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This GDB was configured as "i386-unknown-freebsd"...
panic: page fault
panic messages:
---
Fatal trap 12: page fault while in kernel mode
fault virtual address = 0x6c
fault code  = supervisor write, page not present
instruction pointer = 0x8:0xc05e3c7d
stack pointer         = 0x10:0xd1f24c48
frame pointer         = 0x10:0xd1f24c8c
code segment  = base 0x0, limit 0xfffff, type 0x1b
   = DPL 0, pres 1, def32 1, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process  = 1951 (umount)
trap number  = 12
panic: page fault

syncing disks, buffers remaining... 2638 2638 2638 2638 2638 2638 2638 2638
2638 2638 2638 2638 2638 2638 2638 2638 2638 2638 2638 2638
giving up on 2442 buffers
Uptime: 9h2m24s
Dumping 319 MB
 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256 272 288 304
---
Reading symbols from
/usr/obj/usr/src/sys/server/modules/usr/src/sys/modules/acpi/acpi.ko.debug..
.done.
Loaded symbols for
/usr/obj/usr/src/sys/server/modules/usr/src/sys/modules/acpi/acpi.ko.debug
#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
240  dumping++;
(kgdb) list *0xc05e3c7d
0xc05e3c7d is in ffs_unmount (/usr/src/sys/ufs/ffs/ffs_vfsops.c:990).
985   if (error) {
986    fs->fs_clean = 0;
987    return (error);
988   }
989  }
990  ump->um_devvp->v_rdev->si_mountpoint = NULL;
991
992  vinvalbuf(ump->um_devvp, V_SAVE, NOCRED, td, 0, 0);
993  /* XXX: see comment above VOP_OPEN */
994 #ifdef notyet
(kgdb) backtrace
#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
#1  0xc04c3b99 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:372
#2  0xc04c3f78 in panic () at /usr/src/sys/kern/kern_shutdown.c:550
#3  0xc0646db6 in trap_fatal (frame=0xd1f24c08, eva=0) at
/usr/src/sys/i386/i386/trap.c:821
#4  0xc0646a52 in trap_pfault (frame=0xd1f24c08, usermode=0, eva=108) at
/usr/src/sys/i386/i386/trap.c:735
#5  0xc06465ad in trap (frame=
      {tf_fs = 24, tf_es = 16, tf_ds = 16, tf_edi = -1009713920, tf_esi
= -999817216, tf_ebp = -772649844, tf_isp = -772649932, tf_ebx = 0, tf_edx =
4, tf_ecx = -1066665592, tf_eax = 0, tf_trapno = 12, tf_err = 2, tf_eip
= -1067565955, tf_cs = 8, tf_eflags = 66118, tf_esp = -1009713920, tf_ss =
1}) at /usr/src/sys/i386/i386/trap.c:420
#6  0xc06377b8 in calltrap () at {standard input}:94
#7  0xc051e644 in dounmount (mp=0xc30fbc00, flags=-999817216, td=0xc3d0fd00)
at /usr/src/sys/kern/vfs_mount.c:1144
#8  0xc051e3cb in unmount (td=0xc4645500, uap=0xd1f24d14) at
/usr/src/sys/kern/vfs_mount.c:1083
#9  0xc0647140 in syscall (frame=
      {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 134523407, tf_esi =
134536705, tf_ebp = -1077942936, tf_isp = -772649612, tf_ebx = -1077943024,
tf_edx = 25, tf_ecx = 0, tf_eax = 22, tf_trapno = 12, tf_err = 2, tf_eip =
671874959, tf_cs = 31, tf_eflags = 518, tf_esp = -1077943124, tf_ss = 47})
at /usr/src/sys/i386/i386/trap.c:1010
#10 0xc063780d in Xint0x80_syscall () at {standard input}:136
---Can't read userspace from dump, or kernel process---

(kgdb) quit


server# dmesg
Copyright (c) 1992-2004 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
 The Regents of the University of California. All rights reserved.
FreeBSD 5.2.1-RELEASE #0: Wed Feb 25 01:05:40 GMT 2004
    hywel_at_server.hmallett.co.uk:/usr/obj/usr/src/sys/server
Preloaded elf kernel "/boot/kernel/kernel" at 0xc07b0000.
Preloaded elf module "/boot/kernel/acpi.ko" at 0xc07b01f4.
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Pentium II/Pentium II Xeon/Celeron (267.27-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x652  Stepping = 2

Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,
PAT,PSE36,MMX,FXSR>
real memory  = 335478784 (319 MB)
avail memory = 320430080 (305 MB)
Pentium Pro MTRR support enabled
npx0: [FAST]
npx0: <math processor> on motherboard
npx0: INT 16 interface
acpi0: <QDIGRP AWRDACPI> on motherboard
pcibios: BIOS version 2.10
Using $PIR table, 6 entries at 0xc00fdb90
acpi0: Power Button (fixed)
Timecounter "ACPI-safe" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x4008-0x400b on acpi0
acpi_cpu0: <CPU> on acpi0
pcib0: <ACPI Host-PCI bridge> port 0x5000-0x500f,0x4000-0x4041,0xcf8-0xcff
on acpi0
pci0: <ACPI PCI bus> on pcib0
pcib0: slot 7 INTD is routed to irq 11
pcib0: slot 10 INTA is routed to irq 10
agp0: <Intel 82443LX (440 LX) host to PCI bridge> mem 0xe4000000-0xe43fffff
at device 0.0 on pci0
pcib1: <PCI-PCI bridge> at device 1.0 on pci0
pci1: <PCI bus> on pcib1
isab0: <PCI-ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel PIIX4 UDMA33 controller> port 0xf000-0xf00f at device 7.1 on
pci0
ata0: at 0x1f0 irq 14 on atapci0
ata0: [MPSAFE]
ata1: at 0x170 irq 15 on atapci0
ata1: [MPSAFE]
uhci0: <Intel 82371AB/EB (PIIX4) USB controller> port 0xe000-0xe01f irq 11
at device 7.2 on pci0
usb0: <Intel 82371AB/EB (PIIX4) USB controller> on uhci0
usb0: USB revision 1.0
uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
pci0: <bridge, PCI-unknown> at device 7.3 (no driver attached)
xl0: <3Com 3c905C-TX Fast Etherlink XL> port 0xe400-0xe47f mem
0xe4401000-0xe440107f irq 10 at device 10.0 on pci0
xl0: Ethernet address: 00:01:02:e3:3b:d0
miibus0: <MII bus> on xl0
ukphy0: <Generic IEEE 802.3u media interface> on miibus0
ukphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
pci0: <display, VGA> at device 12.0 (no driver attached)
fdc0: <Enhanced floppy controller (i82077, NE72065 or clone)> port
0x3f7,0x3f2-0x3f5 irq 6 drq 2 on acpi0
fdc0: FIFO enabled, 8 bytes threshold
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
atkbdc0: <Keyboard controller (i8042)> port 0x64,0x60 irq 1 on acpi0
atkbd0: <AT Keyboard> flags 0x1 irq 1 on atkbdc0
kbd0 at atkbd0
orm0: <Option ROM> at iomem 0xc0000-0xc7fff on isa0
pmtimer0 on isa0
sc0: <System console> on isa0
sc0: VGA <16 virtual consoles, flags=0x200>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
sio0: configured irq 4 not in bitmap of probed irqs 0
sio0: port may not be enabled
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 8250 or not responding
sio1: configured irq 3 not in bitmap of probed irqs 0
sio1: port may not be enabled
Timecounter "TSC" frequency 267274051 Hz quality 800
Timecounters tick every 10.000 msec
acpi_cpu: throttling enabled, 8 steps (100% to 12.5%), currently 100.0%
GEOM: create disk ad0 dp=0xc30bc960
ad0: 8693MB <IBM-DJNA-370910> [17662/16/63] at ata0-master UDMA33
GEOM: create disk ad1 dp=0xc30bc860
ad1: 190782MB <WDC WD2000JB-00EVA0> [387621/16/63] at ata0-slave UDMA33
GEOM: create disk ad2 dp=0xc30bc260
ad2: 117800MB <IC35L120AVV207-0> [239340/16/63] at ata1-master UDMA33
Mounting root from ufs:/dev/ad0s1a
WARNING: / was not properly dismounted
WARNING: /tmp was not properly dismounted
WARNING: /usr was not properly dismounted
WARNING: /var was not properly dismounted
WARNING: /usr/home was not properly dismounted
Accounting enabled