Help diagnosing system hangs?

Eric Rescorla ekr at
Tue Aug 23 06:48:52 GMT 2005

I've recently been experiencing frequent hangs with FreeBSD 5.3-RELEASE-p20.
Strangely, this didn't appear to happen with 5.3-RELEASE or before
a few months ago.

My platform is a P4-2.8 GHz (dmesg appended at end).

The behavior is that X freezes (sorry, I can't say if the clock is still
working because I forgot to check) and sshing into the box hangs.  A
hard reboot clears things and the box starts normally, except that it
fscks as expected. Nothing appears in /var/log/messages, etc.

Because this problem started fairly recently, my one guess is that this
is somehow related to the hyperthreading fix in SA-05:09. This processor
allegedly has hyperthreading but I'm running GENERIC. Any possibility
this could be responsible for hanging somehow?

If this isn't a likely culprit, I'm assuming that the next step is to
try to debug the hang with DDB. There's one added difficulty here which
is that I'm using a Matrox P650 and for some reason the X drivers are
screwy so that once you've entered X any attempt to use the virtual
consoles just gets you a blank screen. So, while I've rebuilt the kernel
with DDB, I suspect that I won't actually be able to force the system
console into debugging mode. I assume that this means I need a serial
console but based on the Handbook serial console section it looks like
I can't use a serial console along with the normal console, and since
I want to use X, that would be bad. Am I misreading this?

Any help FreeBSDers can offer would be much appreciated.


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 5.3-RELEASE-p20 #0: Wed Jul 27 05:56:48 PDT 2005
    root at
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz (2798.67-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf25  Stepping = 5
  Hyperthreading: 2 logical CPUs
real memory  = 1072889856 (1023 MB)
avail memory = 1040326656 (992 MB)
ioapic0 <Version 2.0> irqs 0-23 on motherboard
npx0: [FAST]
npx0: <math processor> on motherboard
npx0: INT 16 interface
acpi0: <A M I OEMRSDT> on motherboard
acpi0: Power Button (fixed)
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0
cpu0: <ACPI CPU> port 0x530-0x537 on acpi0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci0: <ACPI PCI bus> on pcib0
agp0: <Intel 82875P host to AGP bridge> mem 0xf4000000-0xf7ffffff at device 0.0 on pci0
pcib1: <ACPI PCI-PCI bridge> at device 1.0 on pci0
pcib1: could not get PCI interrupt routing table for \\_SB_.PCI0.P0P1 - AE_NOT_FOUND
pci1: <ACPI PCI bus> on pcib1
pci1: <display, VGA> at device 0.0 (no driver attached)
pcib2: <ACPI PCI-PCI bridge> at device 3.0 on pci0
pci2: <ACPI PCI bus> on pcib2
em0: <Intel(R) PRO/1000 Network Connection, Version - 1.7.35> port 0xcf80-0xcf9f mem 0xfe9e0000-0xfe9fffff irq 18 at device 1.0 on pci2
em0: Ethernet address: 00:0e:a6:1c:7e:4d
em0:  Speed:N/A  Duplex:N/A
uhci0: <Intel 82801EB (ICH5) USB controller USB-A> port 0xef00-0xef1f irq 16 at device 29.0 on pci0
usb0: <Intel 82801EB (ICH5) USB controller USB-A> 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
uhci1: <Intel 82801EB (ICH5) USB controller USB-B> port 0xef20-0xef3f irq 19 at device 29.1 on pci0
usb1: <Intel 82801EB (ICH5) USB controller USB-B> on uhci1
usb1: USB revision 1.0
uhub1: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub1: 2 ports with 2 removable, self powered
uhci2: <Intel 82801EB (ICH5) USB controller USB-C> port 0xef40-0xef5f irq 18 at device 29.2 on pci0
usb2: <Intel 82801EB (ICH5) USB controller USB-C> on uhci2
usb2: USB revision 1.0
uhub2: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub2: 2 ports with 2 removable, self powered
uhci3: <Intel 82801EB (ICH5) USB controller USB-D> port 0xef80-0xef9f irq 16 at device 29.3 on pci0
usb3: <Intel 82801EB (ICH5) USB controller USB-D> on uhci3
usb3: USB revision 1.0
uhub3: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub3: 2 ports with 2 removable, self powered
pci0: <serial bus, USB> at device 29.7 (no driver attached)
pcib3: <ACPI PCI-PCI bridge> at device 30.0 on pci0
pci3: <ACPI PCI bus> on pcib3
fwohci0: <VIA Fire II (VT6306)> port 0xdc00-0xdc7f mem 0xfeaff800-0xfeafffff irq 20 at device 3.0 on pci3
fwohci0: OHCI version 1.0 (ROM=1)
fwohci0: No. of Isochronous channels is 8.
fwohci0: EUI64 00:e0:18:00:00:4b:c3:e5
fwohci0: Phy 1394a available S400, 3 ports.
fwohci0: Link S400, max_rec 2048 bytes.
firewire0: <IEEE1394(FireWire) bus> on fwohci0
fwe0: <Ethernet over FireWire> on firewire0
if_fwe0: Fake Ethernet address: 02:e0:18:4b:c3:e5
fwe0: Ethernet address: 02:e0:18:4b:c3:e5
fwe0: if_start running deferred for Giant
sbp0: <SBP-2/SCSI over FireWire> on firewire0
fwohci0: Initiate bus reset
fwohci0: node_id=0xc800ffc0, gen=1, CYCLEMASTER mode
firewire0: 1 nodes, maxhop <= 0, cable IRM = 0 (me)
firewire0: bus manager 0 (me)
em1: <Intel(R) PRO/1000 Network Connection, Version - 1.7.35> port 0xdf00-0xdf3f mem 0xfea80000-0xfea9ffff,0xfeaa0000-0xfeabffff irq 20 at device 12.0 on pci3
em1: Ethernet address: 00:0e:0c:05:0d:95
em1:  Speed:N/A  Duplex:N/A
isab0: <PCI-ISA bridge> at device 31.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel ICH5 UDMA100 controller> port 0xfc00-0xfc0f,0x376,0x170-0x177,0x3f6,0x1f0-0x1f7 at device 31.1 on pci0
ata0: channel #0 on atapci0
ata1: channel #1 on atapci0
atapci1: <Intel ICH5 SATA150 controller> port 0xef60-0xef6f,0xefa8-0xefab,0xefa0-0xefa7,0xefac-0xefaf,0xefe0-0xefe7 irq 18 at device 31.2 on pci0
ata2: channel #0 on atapci1
ata3: channel #1 on atapci1
pci0: <serial bus, SMBus> at device 31.3 (no driver attached)
pcm0: <Intel ICH5 (82801EB)> port 0xee80-0xeebf,0xe800-0xe8ff mem 0xfebff400-0xfebff4ff,0xfebff800-0xfebff9ff irq 17 at device 31.5 on pci0
pcm0: <Analog Devices AD1985 AC97 Codec>
acpi_button0: <Power Button> on acpi0
atkbdc0: <Keyboard controller (i8042)> port 0x64,0x60 irq 1 on acpi0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]
psm0: <PS/2 Mouse> irq 12 on atkbdc0
psm0: model IntelliMouse Explorer, device ID 4
sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
sio0: type 16550A
fdc0: <floppy drive controller (FDE)> port 0x3f7,0x3f0-0x3f5 irq 6 drq 2 on acpi0
fdc0: [FAST]
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
ppc0: <ECP parallel printer port> port 0x778-0x77b,0x378-0x37f irq 7 drq 3 on acpi0
ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
ppc0: FIFO with 16/16/9 bytes threshold
ppbus0: <Parallel port bus> on ppc0
plip0: <PLIP network interface> on ppbus0
lpt0: <Printer> on ppbus0
lpt0: Interrupt-driven port
ppi0: <Parallel I/O> on ppbus0
orm0: <ISA Option ROM> at iomem 0xc0000-0xc8fff on isa0
pmtimer0 on isa0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
sio1: configured irq 3 not in bitmap of probed irqs 0
sio1: port may not be enabled
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
Timecounter "TSC" frequency 2798669792 Hz quality 800
Timecounters tick every 10.000 msec
em1: Link is up 100 Mbps Half Duplex
acd0: DVDR <PLEXTOR DVDR PX-708A/1.04> at ata1-master UDMA33
em0: Link is up 100 Mbps Half Duplex
ad4: 190782MB <WDC WD2000JD-00FYB0/02.05D02> [387621/16/63] at ata2-master SATA150
Mounting root from ufs:/dev/ad4s1a
WARNING: / was not properly dismounted
WARNING: /usr was not properly dismounted
/usr: mount pending error: blocks 180 files 1
/usr: superblock summary recomputed
WARNING: /var was not properly dismounted
/var: superblock summary recomputed
em0: Link is up 100 Mbps Half Duplex
em1: Link is up 100 Mbps Half Duplex

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