Bug 24913

Basic system info:  4.2-STABLE on a AMD K6-2 500 w/ a soyo motherboard, 128megs of RAM, USB keyboard&mouse; linksys etherfast nic; USR external modem; Quantum Fireball 10GB, Samsung DVD-ROM.. see my dmesg below for more info.

This appears to be one of those annoying random bugs, it seems to occur when there's a PPP connection through ppp and high CPU activity(dnetc is normally enough to make it eventually panic).
The ONLY time it will panic is if PPP is running, I am sure that this is related because everytime I am able to see the panic info, PPP is the current process.

Now, oddly enough, I didn't have this problem while running 4.2-RELEASE a while ago, so I attempted to find a tempory work-around for the bug and degrade back to 4.2-RELEASE.
This did not work as I thought it would.  It still eventually locked upped while running ppp&dnetc.


anyways, here is fun stuff:

I did a nm /kernel | grep, and the instruction pointer appeared to be in T poll, well it didn't point directly to it, but I removed the some of the ending chars, and it finally came up with T poll, so this may not be accurate, I'm not sure about it.

kernel panic info:

Fata trap 12 : page fault while in kernel mode
fault virtual address = 0x1
fault cod = supervisor read, page not pressent
instruction pointer = 0x8:0xc016b45a
stack pointer = 0x10:0xc93d2dac
frame pointer = 0x10:0xc93d2dcc
code segment = base rx0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, def 32 1, gran 1
processor eflage - interrupt enabled, resume, IOPL=0
current process = 2495(ppp)
interrupt mask = none
trap number 12
panic : page fault


dmesg info:

Copyright (c) 1992-2000 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 4.2-STABLE #0: Tue Feb  6 11:09:21 MST 2001
    diomed@cocytus.2y.net:/usr/src/sys/compile/COCYTUS
Timecounter "i8254"  frequency 1193182 Hz
CPU: AMD-K6(tm) 3D processor (501.14-MHz 586-class CPU)
  Origin = "AuthenticAMD"  Id = 0x58c  Stepping = 12
  Features=0x8021bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,PGE,MMX>
  AMD Features=0x80000800<SYSCALL,3DNow!>
real memory  = 134152192 (131008K bytes)
avail memory = 126545920 (123580K bytes)
Preloaded elf kernel "kernel" at 0xc03f3000.
VESA: v3.0, 4096k memory, flags:0x1, mode table:0xc0379102 (1000022)
VESA: NVidia
K6-family MTRR support enabled (2 registers)
md0: Malloc disk
npx0: <math processor> on motherboard
npx0: INT 16 interface
pcib0: <Host to PCI bridge> on motherboard
pci0: <PCI bus> on pcib0
pcib2: <VIA 82C598MVP (Apollo MVP3) PCI-PCI (AGP) bridge> at device 1.0 on pci0
pci1: <PCI bus> on pcib2
pci1: <NVidia GeForce 256 graphics accelerator> at 0.0 irq 11
isab0: <VIA 82C586 PCI-ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <VIA 82C586 ATA33 controller> port 0xe000-0xe00f at device 7.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
uhci0: <VIA 83C572 USB controller> port 0xe400-0xe41f irq 10 at device 7.2 on pci0
usb0: <VIA 83C572 USB controller> on uhci0
usb0: USB revision 1.0
uhub0: VIA UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
uhub1: Mitsumi Electric Hub in Apple Extended USB Keyboard, class 9/0, rev 1.10/1.22, addr 2
uhub1: 3 ports with 2 removable, bus powered
ukbd0: Mitsumi Electric Apple Extended USB Keyboard, rev 1.10/1.22, addr 3, iclass 3/1
kbd0 at ukbd0
uhid0: Mitsumi Electric Apple Extended USB Keyboard, rev 1.10/1.22, addr 3, iclass 3/0
ums0: Logitech N48, rev 1.00/4.01, addr 4, iclass 3/1
ums0: 3 buttons and Z dir.
pcm0: <AudioPCI ES1371> port 0xe800-0xe83f irq 12 at device 10.0 on pci0
dc0: <LC82C115 PNIC II 10/100BaseTX> port 0xec00-0xecff mem 0xdd000000-0xdd0000ff irq 5 at device 11.0 on pci0
dc0: Ethernet address: 00:a0:cc:e0:4a:9b
miibus0: <MII bus> on dc0
dcphy0: <Intel 21143 NWAY media interface> on miibus0
dcphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
pcib1: <Host to PCI bridge> on motherboard
pci2: <PCI bus> on pcib1
fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
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=0x300>
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
ppc0: Generic chipset (EPP/NIBBLE) in COMPATIBLE mode
plip0: <PLIP network interface> on ppbus0
lpt0: <Printer> on ppbus0
lpt0: Interrupt-driven port
ppi0: <Parallel I/O> on ppbus0
IPsec: Initialized Security Association Processing.
ata0-master: DMA limited to UDMA33, non-ATA66 compliant cable
ad0: 9787MB <QUANTUM FIREBALLlct10 10> [19885/16/63] at ata0-master UDMA33
acd0: DVD-ROM <SAMSUNG DVD-ROM SD-612> at ata0-slave using WDMA2
Mounting root from ufs:/dev/ad0s1a
WARNING: / was not properly dismounted
sio0: 1 more silo overflow (total 1)



kernel configuration:

machine         i386
cpu     I586_CPU
options CPU_WT_ALLOC
ident           COCYTUS
maxusers        64
options     COMPAT_43
options     SCSI_DELAY=15000
options     UCONSOLE
options     USERCONFIG
options     VISUAL_USERCONFIG
options     KTRACE
options     SYSVSHM
options     SYSVMSG
options     SYSVSEM
options     P1003_1B
options     _KPOSIX_PRIORITY_SCHEDULING
options     ICMP_BANDLIM
options     KBD_INSTALL_CDEV

options         FFS
options         FFS_ROOT
options         SOFTUPDATES
options         MFS
options         MD_ROOT
options         NFS
options         NFS_ROOT
options         EXT2FS
options         MSDOSFS
options         CD9660
options         CD9660_ROOT
options     PROCFS
options     FDESC
options     KERNFS
options     NTFS
options     NULLFS

options     PORTAL
options     UMAPFS
options     UNION

options     INET
options     INET6
options     IPSEC
options     IPSEC_ESP

options     IPX
options     NETATALK

device          isa
device          pci

device          fdc0    at isa? port IO_FD1 irq 6 drq 2
device          fd0     at fdc0 drive 0
device          ata0    at isa? port IO_WD1 irq 14
device          ata1    at isa? port IO_WD2 irq 15
device          ata
device          atadisk
device          atapicd
device          atapifd
device          atapist
options         ATA_STATIC_ID
options         ATA_ENABLE_ATAPI_DMA

options         SYM_SETUP_LP_PROBE_MAP=0x40


device          scbus
device          da

device          atkbdc0 at isa? port IO_KBD
device          atkbd0  at atkbdc? irq 1 flags 0x1
device          psm0    at atkbdc? irq 12
device          vga0    at isa?
options VESA

pseudo-device   splash

device          sc0     at isa? flags 0x100
options SC_ALT_MOUSE_IMAGE

device          npx0    at nexus? port IO_NPX irq 13


device          apm0    at nexus? disable flags 0x20

device          sio0    at isa? port IO_COM1 flags 0x10 irq 4
device          sio1    at isa? port IO_COM2 irq 3


device          ppc0    at isa? irq 7
device          ppbus
device          lpt
device          plip
device          ppi
device          miibus
device          dc

pseudo-device   loop
pseudo-device   ether
pseudo-device   sl      1
pseudo-device   ppp     1
pseudo-device   tun
pseudo-device   pty
pseudo-device   md
pseudo-device   gif     4
pseudo-device   faith   1

pseudo-device   bpf


device          uhci
device          ohci
device          usb
device          ugen
device          uhid
device          ukbd
device          ulpt
device          umass
device          ums
device          uscanner

device pcm


I hope this is enough information.  If you need anymore information or have any questions, please e-mail me(diomed@mac.com).

Fix: 

workaround: don't run dnetc w/ppp.  avoiding high CPU usage seems to work well, but a little every now and then doesn't seem to hurt..

no real fix that I know of.
How-To-Repeat: ppp -ddial -nat service + dnetc

stir gently and wait a while, possibly a few hours.

just have ppp and dnetc running at the same time, and it should panic eventually.  I'm normally connected to the internet when it does panic.