2.6.8-rc2 4K stack overflow

[linux@horizon.com]

Just a crash report.  Machine locked hard - no caps lock, no ping.

Machine mostly idle.  Amanda network backup was running, but not daily cron.

Backtrace copied by hand. (I didn't copy the leading addresses.)
FWIW, only one partition (a RAID-0 non-critical data partition) is
mounted with ext2.

.config follows.  Compiler is GCC 3.3.4 (Debian 3.3.4-3)  Hardware is
Intel Celeron, 440BX motherboard.

Hopefully it helps someone.  I don't have frame pointers enabled, so I
assume the confusing bits of the backtrace are clutter misidentified as
a return address.

<top of visible screen>
do_exit+0x76/0x2c0
die+0xc5/0xd0
do_page_fault+0x0/0x528
do_page_fault+0x277/0x528
scrup+0xf3/0x110
vt_console_printf+0x1e7/0x2e0
do_page_fault+0x0/0x527
error_code+0x2d/0x38
mm_release+0x38/0xa0
common_interrupt+0x18/0x20
do_exit+0x76/0x2c0
die+0xc5/0xd0
do_invalid_op+0x0/0xb0
do_invalid_op+0xac/0xb0
free_pages_bulk+0x205/0x220
free_hot_cold_page+0xbd/0xe0
zap_pte_range+0x14b/0x240
zap_pmd_range+0x4b/0x70
unmap_page_range+0x3d/0x70
unmap_vmas+0xfe/0x1b0
exit_mmap+0x69/0x130
mmput+0x40/0x60
do_exit+0x11b/0x2c0
die+0xc5/0xd0
do_invalid_op+0x0/0xb0
do_invalid_op+0xac/0xb0
buffered_rmqueue+0xfc/0x150
ext2_alloc_branch+0x2d/0x1f0
ext2_get_block+0x297/0x320
error_code+0x2d/0x38
buffered_rmqueue+0xfc/0x150
__alloc_pages+0x9f/0x320
find_lock_page+0x19/0x90
generic_file_aio_write_nolock+0x2b8/0x9c0
buffered_rmqueue+0xc5/0x150
do_select+0x18a/0x2b0
generic_file_write_nolock+0x5a/0x80
do_sync_read+0x6d/0xa0
generic_file_write+0x3e/0x60
vfs_write+0xb0/0x110
sys_write+0x38/0x60
syscall_call+0x7/0xb
Code: 8b 46 14 48 7e 52 31 d2 b8 00 f0 ff ff 89 93 5c 01 00 00 89
 <1>Unable to handle kernel NULL pointer dereferencedo_IRQ: Stack overflow: 316


And here is 'grep [A-Z] .config':

CONFIG_X86=y
CONFIG_MMU=y
CONFIG_UID16=y
CONFIG_GENERIC_ISA_DMA=y
CONFIG_EXPERIMENTAL=y
CONFIG_CLEAN_COMPILE=y
CONFIG_STANDALONE=y
CONFIG_BROKEN_ON_SMP=y
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_SYSCTL=y
CONFIG_LOG_BUF_SHIFT=15
CONFIG_HOTPLUG=y
CONFIG_IKCONFIG=y
CONFIG_KALLSYMS=y
CONFIG_FUTEX=y
CONFIG_EPOLL=y
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
CONFIG_X86_PC=y
CONFIG_MPENTIUMII=y
CONFIG_X86_CMPXCHG=y
CONFIG_X86_XADD=y
CONFIG_X86_L1_CACHE_SHIFT=5
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_INTEL_USERCOPY=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
CONFIG_X86_UP_APIC=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_TSC=y
CONFIG_X86_MCE=y
CONFIG_X86_MSR=y
CONFIG_NOHIGHMEM=y
CONFIG_MTRR=y
CONFIG_REGPARM=y
CONFIG_ACPI_BOOT=y
CONFIG_PCI=y
CONFIG_PCI_GOANY=y
CONFIG_PCI_BIOS=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_MMCONFIG=y
CONFIG_PCI_NAMES=y
CONFIG_ISA=y
CONFIG_PCMCIA=y
CONFIG_PCMCIA_DEBUG=y
CONFIG_YENTA=y
CONFIG_CARDBUS=y
CONFIG_PCMCIA_PROBE=y
CONFIG_BINFMT_ELF=y
CONFIG_PREVENT_FIRMWARE_BUILD=y
CONFIG_PARPORT=y
CONFIG_PARPORT_PC=y
CONFIG_PARPORT_PC_CML1=y
CONFIG_PARPORT_PC_FIFO=y
CONFIG_PARPORT_PC_SUPERIO=y
CONFIG_PARPORT_1284=y
CONFIG_BLK_DEV_FD=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_CRYPTOLOOP=y
CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y
CONFIG_BLK_DEV_IDEDISK=y
CONFIG_IDEDISK_MULTI_MODE=y
CONFIG_IDE_TASKFILE_IO=y
CONFIG_IDE_GENERIC=y
CONFIG_BLK_DEV_IDEPCI=y
CONFIG_IDEPCI_SHARE_IRQ=y
CONFIG_BLK_DEV_GENERIC=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_IDEDMA_PCI_AUTO=y
CONFIG_BLK_DEV_ADMA=y
CONFIG_BLK_DEV_PIIX=y
CONFIG_BLK_DEV_PDC202XX_NEW=y
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_IDEDMA_AUTO=y
CONFIG_SCSI=y
CONFIG_SCSI_PROC_FS=y
CONFIG_BLK_DEV_SD=y
CONFIG_CHR_DEV_ST=y
CONFIG_BLK_DEV_SR=y
CONFIG_CHR_DEV_SG=y
CONFIG_SCSI_CONSTANTS=y
CONFIG_SCSI_LOGGING=y
CONFIG_SCSI_BUSLOGIC=y
CONFIG_SCSI_OMIT_FLASHPOINT=y
CONFIG_SCSI_QLA2XXX=y
CONFIG_MD=y
CONFIG_BLK_DEV_MD=y
CONFIG_MD_RAID0=y
CONFIG_MD_RAID1=y
CONFIG_NET=y
CONFIG_PACKET=y
CONFIG_PACKET_MMAP=y
CONFIG_NETLINK_DEV=y
CONFIG_UNIX=y
CONFIG_NET_KEY=y
CONFIG_INET=y
CONFIG_IP_ADVANCED_ROUTER=y
CONFIG_IP_ROUTE_VERBOSE=y
CONFIG_NET_IPIP=y
CONFIG_SYN_COOKIES=y
CONFIG_INET_AH=y
CONFIG_INET_ESP=y
CONFIG_INET_IPCOMP=y
CONFIG_NETFILTER=y
CONFIG_IP_NF_CONNTRACK=y
CONFIG_IP_NF_FTP=y
CONFIG_IP_NF_IRC=y
CONFIG_IP_NF_QUEUE=y
CONFIG_IP_NF_IPTABLES=y
CONFIG_IP_NF_MATCH_LIMIT=y
CONFIG_IP_NF_MATCH_MARK=y
CONFIG_IP_NF_MATCH_RECENT=y
CONFIG_IP_NF_MATCH_ECN=y
CONFIG_IP_NF_MATCH_HELPER=y
CONFIG_IP_NF_MATCH_STATE=y
CONFIG_IP_NF_MATCH_CONNTRACK=y
CONFIG_IP_NF_FILTER=y
CONFIG_IP_NF_TARGET_REJECT=y
CONFIG_IP_NF_NAT=y
CONFIG_IP_NF_NAT_NEEDED=y
CONFIG_IP_NF_TARGET_MASQUERADE=y
CONFIG_IP_NF_TARGET_REDIRECT=y
CONFIG_IP_NF_NAT_IRC=y
CONFIG_IP_NF_NAT_FTP=y
CONFIG_IP_NF_MANGLE=y
CONFIG_IP_NF_TARGET_TOS=y
CONFIG_IP_NF_TARGET_ECN=y
CONFIG_IP_NF_TARGET_MARK=y
CONFIG_IP_NF_TARGET_LOG=y
CONFIG_IP_NF_TARGET_ULOG=y
CONFIG_IP_NF_TARGET_NOTRACK=y
CONFIG_IP_NF_RAW=y
CONFIG_IP_NF_MATCH_ADDRTYPE=y
CONFIG_XFRM=y
CONFIG_XFRM_USER=y
CONFIG_NET_SCHED=y
CONFIG_NET_SCH_CBQ=y
CONFIG_NET_SCH_HTB=y
CONFIG_NET_SCH_HFSC=y
CONFIG_NET_SCH_RED=y
CONFIG_NET_SCH_TBF=y
CONFIG_NET_SCH_NETEM=y
CONFIG_NET_SCH_INGRESS=y
CONFIG_NET_CLS=y
CONFIG_NET_CLS_TCINDEX=y
CONFIG_NET_CLS_ROUTE4=y
CONFIG_NET_CLS_ROUTE=y
CONFIG_NET_CLS_FW=y
CONFIG_NET_CLS_U32=y
CONFIG_NETDEVICES=y
CONFIG_DUMMY=y
CONFIG_NET_ETHERNET=y
CONFIG_MII=y
CONFIG_NET_TULIP=y
CONFIG_TULIP=y
CONFIG_TULIP_MWI=y
CONFIG_TULIP_MMIO=y
CONFIG_TULIP_NAPI=y
CONFIG_TULIP_NAPI_HW_MITIGATION=y
CONFIG_NET_RADIO=y
CONFIG_PCMCIA_WAVELAN=y
CONFIG_PCMCIA_NETWAVE=y
CONFIG_PCMCIA_RAYCS=y
CONFIG_AIRO=y
CONFIG_HERMES=y
CONFIG_PCMCIA_HERMES=y
CONFIG_AIRO_CS=y
CONFIG_NET_WIRELESS=y
CONFIG_NET_PCMCIA=y
CONFIG_PPP=y
CONFIG_PPP_FILTER=y
CONFIG_PPP_ASYNC=y
CONFIG_PPP_DEFLATE=y
CONFIG_PPP_BSDCOMP=y
CONFIG_INPUT=y
CONFIG_INPUT_MOUSEDEV=y
CONFIG_INPUT_MOUSEDEV_PSAUX=y
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
CONFIG_SOUND_GAMEPORT=y
CONFIG_SERIO=y
CONFIG_SERIO_I8042=y
CONFIG_INPUT_KEYBOARD=y
CONFIG_KEYBOARD_ATKBD=y
CONFIG_INPUT_MOUSE=y
CONFIG_MOUSE_PS2=y
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_CORE=y
CONFIG_UNIX98_PTYS=y
CONFIG_PRINTER=y
CONFIG_AGP=y
CONFIG_AGP_INTEL=y
CONFIG_VIDEO_SELECT=y
CONFIG_VGA_CONSOLE=y
CONFIG_DUMMY_CONSOLE=y
CONFIG_EXT2_FS=y
CONFIG_EXT3_FS=y
CONFIG_JBD=y
CONFIG_ISO9660_FS=y
CONFIG_JOLIET=y
CONFIG_FAT_FS=y
CONFIG_MSDOS_FS=y
CONFIG_VFAT_FS=y
CONFIG_FAT_DEFAULT_CODEPAGE=437
CONFIG_FAT_DEFAULT_IOCHARSET="iso8859-1"
CONFIG_PROC_FS=y
CONFIG_PROC_KCORE=y
CONFIG_SYSFS=y
CONFIG_TMPFS=y
CONFIG_RAMFS=y
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
CONFIG_NFSD=y
CONFIG_NFSD_V3=y
CONFIG_NFSD_TCP=y
CONFIG_LOCKD=y
CONFIG_LOCKD_V4=y
CONFIG_EXPORTFS=y
CONFIG_SUNRPC=y
CONFIG_SMB_FS=y
CONFIG_MSDOS_PARTITION=y
CONFIG_NLS=y
CONFIG_NLS_DEFAULT="cp437"
CONFIG_NLS_CODEPAGE_437=y
CONFIG_NLS_ISO8859_1=y
CONFIG_NLS_ISO8859_15=y
CONFIG_DEBUG_KERNEL=y
CONFIG_EARLY_PRINTK=y
CONFIG_DEBUG_STACKOVERFLOW=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_4KSTACKS=y
CONFIG_X86_FIND_SMP_CONFIG=y
CONFIG_X86_MPPARSE=y
CONFIG_CRYPTO=y
CONFIG_CRYPTO_HMAC=y
CONFIG_CRYPTO_MD5=y
CONFIG_CRYPTO_SHA1=y
CONFIG_CRYPTO_DES=y
CONFIG_CRYPTO_TWOFISH=y
CONFIG_CRYPTO_AES=y
CONFIG_CRYPTO_TEA=y
CONFIG_CRYPTO_DEFLATE=y
CONFIG_CRC_CCITT=y
CONFIG_CRC32=y
CONFIG_ZLIB_INFLATE=y
CONFIG_ZLIB_DEFLATE=y
CONFIG_X86_BIOS_REBOOT=y
CONFIG_PC=y