busy buffer problem

[Chris Csanady <csanady@xxxxxxxxx>]

Several years ago, I encountered this annoyance in FreeBSD, and
it seems to have appeared again.  Unfortunately, I don't know how 
long this has been an issue; my machine is headless, and is rarely
rebooted.  Still, I have been hoping to do some developement, and
after I got a serial console hooked up, I was greeted with this most
unwelcome sight:

boot() called on cpu#0
Waiting (max 60 seconds) for system thread vnlru to stop...stopped
Waiting (max 60 seconds) for system thread bufdaemon to stop...stopped
Waiting (max 60 seconds) for system thread syncer to stop...stopped

syncing disks... 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
0xc0d8bcc0 1: dev:ad2, flags:21021024, blkno:6562816, lblkno:6562816
0xc0d79270 2: dev:ad2, flags:21021024, blkno:4010176, lblkno:4010176
giving up on 2 buffers
Debugger("busy buffer problem")

CPU0 stopping CPUs: 0x00000002
 stopped
Stopped at      Debugger+0x34:  movb    $0,in_Debugger.363
db>

I am currently running the latest of the 1.2 release branch, though
it looks like it has been a problem since at least 1.2.2.  (Now that
I have preview installed on another disk, I can confirm that it
happens there as well.)

I have attached my dmesg for reference.  Let me know if there
is anything more I can do to help resolve this issue.

(somewhat unrelated, but is the poor apic interrupt mapping simply
an artifact of my crusty old hardware?)

Thanks,
Chris


Copyright (c) 2003, 2004, 2005 The DragonFly Project.
Copyright (c) 1992-2003 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.
DragonFly 1.2.5-RELEASE #4: Mon Sep 19 15:01:34 CDT 2005
    root@:/usr/obj/usr/src/sys/PPS
TSC clock: 198656034 Hz, i8254 clock: 1193130 Hz
CPU: Pentium Pro (198.67-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x619  Stepping = 9
  Features=0xfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV>
real memory  = 134217728 (131072K bytes)
avail memory = 124489728 (121572K bytes)
Programming 24 pins in IOAPIC #0
DragonFly/MP: Multiprocessor motherboard
 cpu0 (BSP): apic id:  0, version: 0x00040011, at 0xfec08000
 cpu1 (AP):  apic id: 12, version: 0x00040011, at 0xfec08000
 io0 (APIC): apic id: 13, version: 0x00170011, at 0xfec00000
Preloaded elf kernel "/kernel" at 0xc03e0000.
Pentium Pro MTRR support enabled
md0: Malloc disk
pcibios: BIOS version 2.10
npx0: <math processor> on motherboard
npx0: INT 16 interface
pcib0: <Host to PCI bridge> at pcibus 0 on motherboard
pci0: <PCI bus> on pcib0
IOAPIC #0 intpin 18 -> irq 2
IOAPIC #0 intpin 17 -> irq 9
IOAPIC #0 intpin 16 -> irq 10
IOAPIC #0 intpin 19 -> irq 11
fxp0: <Intel 82557 Pro/100 Ethernet> port 0xff40-0xff5f mem
0xfe800000-0xfe8fffff,0xffbe0000-0xffbe0fff irq 2 at device 6.0 on
pci0
installed MI handler for int 2
miibus0: <MII bus> on fxp0
nsphy0: <DP83840 10/100 media interface> on miibus0
nsphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
fxp0: MAC address: 00:a0:c9:55:9e:4f
isab0: <Intel 82371SB PCI to ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel PIIX3 ATA controller> port 0xffa0-0xffaf at device 7.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
installed MI handler for int 14
ata1: at 0x170 irq 15 on atapci0
installed MI handler for int 15
ahc0: <Adaptec aic7880 Ultra SCSI adapter> port 0xfc00-0xfcff mem
0xffbeb000-0xffbebfff irq 9 at device 9.0 on pci0
installed MI handler for int 9
aic7880: Ultra Wide Channel A, SCSI Id=7, 16/253 SCBs
fxp1: <Intel 82559 Pro/100 Ethernet> port 0xfd80-0xfdbf mem
0xfea00000-0xfeafffff,0xffbe2000-0xffbe2fff irq 10 at device 11.0 on
pci0
installed MI handler for int 10
miibus1: <MII bus> on fxp1
inphy0: <i82555 10/100 media interface> on miibus1
inphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
fxp1: MAC address: 00:03:47:e0:23:1f
fxp2: <Intel 82559 Pro/100 Ethernet> port 0xfe80-0xfebf mem
0xfed00000-0xfedfffff,0xffbea000-0xffbeafff irq 9 at device 15.0 on
pci0
miibus2: <MII bus> on fxp2
inphy1: <i82555 10/100 media interface> on miibus2
inphy1:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
fxp2: MAC address: 00:03:47:df:b2:73
fxp3: <Intel 82559 Pro/100 Ethernet> port 0xff00-0xff3f mem
0xff800000-0xff8fffff,0xffbe3000-0xffbe3fff irq 2 at device 17.0 on
pci0
miibus3: <MII bus> on fxp3
inphy2: <i82555 10/100 media interface> on miibus3
inphy2:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
fxp3: MAC address: 00:03:47:e0:20:9f
pci0: <Matrox MGA Millennium 2064W graphics accelerator> at 19.0 irq 11
orm0: <Option ROMs> at iomem
0xc0000-0xc7fff,0xc8000-0xc87ff,0xe9000-0xe9fff,0xea000-0xebfff on
isa0
fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
installed MI handler for int 6
fdc0: FIFO enabled, 8 bytes threshold
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x100>
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A, console
installed MI handler for int 4
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
installed MI handler for int 3
installed MI handler for int 0
APIC_IO: routing 8254 via 8259 and IOAPIC #0 intpin 0
SMP: AP CPU #1 Launched!
ad0: 38154MB <TOSHIBA MK4021GAS> [77520/16/63] at ata0-master WDMA2
ad1: 9671MB <IBM-DTTA-351010> [20960/15/63] at ata0-slave WDMA2
ad2: 190782MB <ST3200822A> [387621/16/63] at ata1-master WDMA2
Waiting 5 seconds for SCSI devices to settle
cd0 at ahc0 bus 0 target 4 lun 0
cd0: <NEC CD-ROM DRIVE:463 1.05> Removable CD-ROM SCSI-2 device 
cd0: 10.000MB/s transfers (10.000MHz, offset 15)
cd0: Attempt to query device size failed: NOT READY, Medium not present
Mounting root from ufs:/dev/ad2s1a
WARNING:  was not properly dismounted