BUG in 2.6.20-rt8

BUG in 2.6.20-rt8

[Paul E. McKenney]

Hello!

I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz Opteron
box.  The machine continued to run a few rounds of kernbench and LTP.
Looks a bit scary -- a tasklet was "stolen" from __tasklet_action().

Thoughts?  In the meantime, kicking it off again to see if it repeats.

						Thanx, Paul

BUG: at kernel/softirq.c:559 __tasklet_action()

Call Trace:
 [<ffffffff8022ec1b>] __tasklet_action+0xdb/0x120
 [<ffffffff8022ee12>] ksoftirqd+0xf3/0x179
 [<ffffffff8022ed1f>] ksoftirqd+0x0/0x179
 [<ffffffff8023be23>] kthread+0xc8/0xf1
 [<ffffffff8020a708>] child_rip+0xa/0x12
 [<ffffffff8023bf27>] kthread_create+0x6e/0x159
 [<ffffffff8023bd5b>] kthread+0x0/0xf1
 [<ffffffff8020a6fe>] child_rip+0x0/0x12

---------------------------
| preempt count: 00000000 ]
| 0-level deep critical section nesting:
----------------------------------------

Config:

#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.20-rt8-autokern1
# Sat Feb 24 17:05:11 2007
#
CONFIG_X86_64=y
CONFIG_64BIT=y
CONFIG_X86=y
CONFIG_GENERIC_TIME=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_ZONE_DMA32=y
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_SEMAPHORE_SLEEPERS=y
CONFIG_MMU=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_X86_CMPXCHG=y
CONFIG_EARLY_PRINTK=y
CONFIG_GENERIC_ISA_DMA=y
CONFIG_GENERIC_IOMAP=y
CONFIG_ARCH_MAY_HAVE_PC_FDC=y
CONFIG_ARCH_POPULATES_NODE_MAP=y
CONFIG_DMI=y
CONFIG_AUDIT_ARCH=y
CONFIG_GENERIC_BUG=y
# CONFIG_ARCH_HAS_ILOG2_U32 is not set
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"

#
# Code maturity level options
#
CONFIG_EXPERIMENTAL=y
CONFIG_LOCK_KERNEL=y
CONFIG_INIT_ENV_ARG_LIMIT=32

#
# General setup
#
CONFIG_LOCALVERSION=""
CONFIG_LOCALVERSION_AUTO=y
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
# CONFIG_IPC_NS is not set
# CONFIG_POSIX_MQUEUE is not set
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_TASKSTATS is not set
# CONFIG_UTS_NS is not set
# CONFIG_AUDIT is not set
# CONFIG_IKCONFIG is not set
# CONFIG_CPUSETS is not set
CONFIG_SYSFS_DEPRECATED=y
# CONFIG_RELAY is not set
CONFIG_INITRAMFS_SOURCE=""
CONFIG_CC_OPTIMIZE_FOR_SIZE=y
CONFIG_SYSCTL=y
# CONFIG_EMBEDDED is not set
CONFIG_UID16=y
CONFIG_SYSCTL_SYSCALL=y
CONFIG_KALLSYMS=y
# CONFIG_KALLSYMS_ALL is not set
# CONFIG_KALLSYMS_EXTRA_PASS is not set
CONFIG_HOTPLUG=y
CONFIG_PRINTK=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_EPOLL=y
CONFIG_SHMEM=y
CONFIG_SLAB=y
CONFIG_VM_EVENT_COUNTERS=y
CONFIG_RT_MUTEXES=y
# CONFIG_TINY_SHMEM is not set
CONFIG_BASE_SMALL=0
# CONFIG_SLOB is not set

#
# Loadable module support
#
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
# CONFIG_MODVERSIONS is not set
# CONFIG_MODULE_SRCVERSION_ALL is not set
# CONFIG_KMOD is not set
CONFIG_STOP_MACHINE=y

#
# Block layer
#
CONFIG_BLOCK=y
# CONFIG_BLK_DEV_IO_TRACE is not set

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
# CONFIG_DEFAULT_AS is not set
# CONFIG_DEFAULT_DEADLINE is not set
CONFIG_DEFAULT_CFQ=y
# CONFIG_DEFAULT_NOOP is not set
CONFIG_DEFAULT_IOSCHED="cfq"

#
# Processor type and features
#
CONFIG_X86_PC=y
# CONFIG_X86_VSMP is not set
CONFIG_MK8=y
# CONFIG_MPSC is not set
# CONFIG_MCORE2 is not set
# CONFIG_GENERIC_CPU is not set
CONFIG_X86_L1_CACHE_BYTES=64
CONFIG_X86_L1_CACHE_SHIFT=6
CONFIG_X86_INTERNODE_CACHE_BYTES=64
CONFIG_X86_TSC=y
CONFIG_X86_GOOD_APIC=y
# CONFIG_MICROCODE is not set
CONFIG_X86_MSR=y
CONFIG_X86_CPUID=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_MTRR=y
CONFIG_SMP=y
# CONFIG_SCHED_SMT is not set
CONFIG_SCHED_MC=y
# CONFIG_TICK_ONESHOT is not set
# CONFIG_NO_HZ is not set
# CONFIG_HIGH_RES_TIMERS is not set
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT_DESKTOP is not set
CONFIG_PREEMPT_RT=y
CONFIG_PREEMPT=y
CONFIG_PREEMPT_SOFTIRQS=y
CONFIG_PREEMPT_HARDIRQS=y
CONFIG_PREEMPT_BKL=y
# CONFIG_CLASSIC_RCU is not set
CONFIG_PREEMPT_RCU=y
# CONFIG_RCU_TRACE is not set
CONFIG_NUMA=y
CONFIG_RWSEM_GENERIC_SPINLOCK=y
CONFIG_K8_NUMA=y
CONFIG_NODES_SHIFT=6
CONFIG_X86_64_ACPI_NUMA=y
# CONFIG_NUMA_EMU is not set
CONFIG_ARCH_DISCONTIGMEM_ENABLE=y
CONFIG_ARCH_DISCONTIGMEM_DEFAULT=y
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_SELECT_MEMORY_MODEL=y
# CONFIG_FLATMEM_MANUAL is not set
CONFIG_DISCONTIGMEM_MANUAL=y
# CONFIG_SPARSEMEM_MANUAL is not set
CONFIG_DISCONTIGMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
CONFIG_NEED_MULTIPLE_NODES=y
# CONFIG_SPARSEMEM_STATIC is not set
# CONFIG_MEMORY_HOTPLUG is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_MIGRATION=y
CONFIG_RESOURCES_64BIT=y
CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID=y
CONFIG_OUT_OF_LINE_PFN_TO_PAGE=y
CONFIG_NR_CPUS=8
# CONFIG_HOTPLUG_CPU is not set
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
CONFIG_HPET_TIMER=y
# CONFIG_HPET_EMULATE_RTC is not set
CONFIG_IOMMU=y
# CONFIG_CALGARY_IOMMU is not set
CONFIG_SWIOTLB=y
CONFIG_X86_MCE=y
CONFIG_X86_MCE_INTEL=y
CONFIG_X86_MCE_AMD=y
# CONFIG_KEXEC is not set
# CONFIG_CRASH_DUMP is not set
CONFIG_PHYSICAL_START=0x200000
CONFIG_SECCOMP=y
# CONFIG_CC_STACKPROTECTOR is not set
# CONFIG_HZ_100 is not set
CONFIG_HZ_250=y
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=250
# CONFIG_REORDER is not set
CONFIG_K8_NB=y
CONFIG_GENERIC_HARDIRQS=y
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_ISA_DMA_API=y
CONFIG_GENERIC_PENDING_IRQ=y

#
# Power management options
#
CONFIG_PM=y
# CONFIG_PM_LEGACY is not set
# CONFIG_PM_DEBUG is not set
# CONFIG_PM_SYSFS_DEPRECATED is not set

#
# ACPI (Advanced Configuration and Power Interface) Support
#
CONFIG_ACPI=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_VIDEO=m
# CONFIG_ACPI_HOTKEY is not set
CONFIG_ACPI_FAN=y
# CONFIG_ACPI_DOCK is not set
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
CONFIG_ACPI_NUMA=y
# CONFIG_ACPI_ASUS is not set
CONFIG_ACPI_IBM=m
# CONFIG_ACPI_IBM_DOCK is not set
CONFIG_ACPI_TOSHIBA=y
CONFIG_ACPI_BLACKLIST_YEAR=0
CONFIG_ACPI_DEBUG=y
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y
CONFIG_X86_PM_TIMER=y
# CONFIG_ACPI_CONTAINER is not set

#
# CPU Frequency scaling
#
# CONFIG_CPU_FREQ is not set

#
# Bus options (PCI etc.)
#
CONFIG_PCI=y
CONFIG_PCI_DIRECT=y
# CONFIG_PCI_MMCONFIG is not set
# CONFIG_PCIEPORTBUS is not set
# CONFIG_PCI_MSI is not set
# CONFIG_PCI_DEBUG is not set
CONFIG_HT_IRQ=y

#
# PCCARD (PCMCIA/CardBus) support
#
# CONFIG_PCCARD is not set

#
# PCI Hotplug Support
#
# CONFIG_HOTPLUG_PCI is not set

#
# Executable file formats / Emulations
#
CONFIG_BINFMT_ELF=y
# CONFIG_BINFMT_MISC is not set
CONFIG_IA32_EMULATION=y
# CONFIG_IA32_AOUT is not set
CONFIG_COMPAT=y
CONFIG_SYSVIPC_COMPAT=y

#
# Networking
#
CONFIG_NET=y

#
# Networking options
#
# CONFIG_NETDEBUG is not set
CONFIG_PACKET=y
# CONFIG_PACKET_MMAP is not set
CONFIG_UNIX=y
CONFIG_XFRM=y
# CONFIG_XFRM_USER is not set
# CONFIG_XFRM_SUB_POLICY is not set
# CONFIG_NET_KEY is not set
CONFIG_INET=y
CONFIG_IP_MULTICAST=y
# CONFIG_IP_ADVANCED_ROUTER is not set
CONFIG_IP_FIB_HASH=y
# CONFIG_IP_PNP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
# CONFIG_IP_MROUTE is not set
# CONFIG_ARPD is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
# CONFIG_INET_XFRM_TUNNEL is not set
# CONFIG_INET_TUNNEL is not set
CONFIG_INET_XFRM_MODE_TRANSPORT=y
CONFIG_INET_XFRM_MODE_TUNNEL=y
CONFIG_INET_XFRM_MODE_BEET=y
CONFIG_INET_DIAG=y
CONFIG_INET_TCP_DIAG=y
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
# CONFIG_IPV6 is not set
# CONFIG_INET6_XFRM_TUNNEL is not set
# CONFIG_INET6_TUNNEL is not set
# CONFIG_NETWORK_SECMARK is not set
# CONFIG_NETFILTER is not set

#
# DCCP Configuration (EXPERIMENTAL)
#
# CONFIG_IP_DCCP is not set

#
# SCTP Configuration (EXPERIMENTAL)
#
# CONFIG_IP_SCTP is not set

#
# TIPC Configuration (EXPERIMENTAL)
#
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
# CONFIG_BRIDGE is not set
# CONFIG_VLAN_8021Q is not set
# CONFIG_DECNET is not set
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set

#
# QoS and/or fair queueing
#
# CONFIG_NET_SCHED is not set

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
# CONFIG_HAMRADIO is not set
# CONFIG_IRDA is not set
# CONFIG_BT is not set
# CONFIG_IEEE80211 is not set

#
# Device Drivers
#

#
# Generic Driver Options
#
CONFIG_STANDALONE=y
CONFIG_PREVENT_FIRMWARE_BUILD=y
# CONFIG_FW_LOADER is not set
# CONFIG_DEBUG_DRIVER is not set
# CONFIG_SYS_HYPERVISOR is not set

#
# Connector - unified userspace <-> kernelspace linker
#
# CONFIG_CONNECTOR is not set

#
# Memory Technology Devices (MTD)
#
# CONFIG_MTD is not set

#
# Parallel port support
#
# CONFIG_PARPORT is not set

#
# Plug and Play support
#
# CONFIG_PNP is not set

#
# Block devices
#
# CONFIG_BLK_DEV_FD is not set
# CONFIG_BLK_CPQ_DA is not set
# CONFIG_BLK_CPQ_CISS_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_UMEM is not set
# CONFIG_BLK_DEV_COW_COMMON is not set
CONFIG_BLK_DEV_LOOP=y
# CONFIG_BLK_DEV_CRYPTOLOOP is not set
# CONFIG_BLK_DEV_NBD is not set
# CONFIG_BLK_DEV_SX8 is not set
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=16
CONFIG_BLK_DEV_RAM_SIZE=4096
CONFIG_BLK_DEV_RAM_BLOCKSIZE=1024
CONFIG_BLK_DEV_INITRD=y
# CONFIG_CDROM_PKTCDVD is not set
# CONFIG_ATA_OVER_ETH is not set

#
# Misc devices
#
# CONFIG_IBM_ASM is not set
# CONFIG_SGI_IOC4 is not set
# CONFIG_TIFM_CORE is not set
# CONFIG_MSI_LAPTOP is not set

#
# ATA/ATAPI/MFM/RLL support
#
CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y

#
# Please see Documentation/ide.txt for help/info on IDE drives
#
# CONFIG_BLK_DEV_IDE_SATA is not set
# CONFIG_BLK_DEV_HD_IDE is not set
CONFIG_BLK_DEV_IDEDISK=y
CONFIG_IDEDISK_MULTI_MODE=y
CONFIG_BLK_DEV_IDECD=y
# CONFIG_BLK_DEV_IDETAPE is not set
# CONFIG_BLK_DEV_IDEFLOPPY is not set
# CONFIG_BLK_DEV_IDESCSI is not set
# CONFIG_IDE_TASK_IOCTL is not set

#
# IDE chipset support/bugfixes
#
CONFIG_IDE_GENERIC=y
# CONFIG_BLK_DEV_CMD640 is not set
CONFIG_BLK_DEV_IDEPCI=y
# CONFIG_IDEPCI_SHARE_IRQ is not set
# CONFIG_BLK_DEV_OFFBOARD is not set
# CONFIG_BLK_DEV_GENERIC is not set
# CONFIG_BLK_DEV_OPTI621 is not set
# CONFIG_BLK_DEV_RZ1000 is not set
CONFIG_BLK_DEV_IDEDMA_PCI=y
# CONFIG_BLK_DEV_IDEDMA_FORCED is not set
CONFIG_IDEDMA_PCI_AUTO=y
# CONFIG_IDEDMA_ONLYDISK is not set
# CONFIG_BLK_DEV_AEC62XX is not set
# CONFIG_BLK_DEV_ALI15X3 is not set
CONFIG_BLK_DEV_AMD74XX=y
# CONFIG_BLK_DEV_ATIIXP is not set
# CONFIG_BLK_DEV_CMD64X is not set
# CONFIG_BLK_DEV_TRIFLEX is not set
# CONFIG_BLK_DEV_CY82C693 is not set
# CONFIG_BLK_DEV_CS5520 is not set
# CONFIG_BLK_DEV_CS5530 is not set
# CONFIG_BLK_DEV_HPT34X is not set
# CONFIG_BLK_DEV_HPT366 is not set
# CONFIG_BLK_DEV_JMICRON is not set
# CONFIG_BLK_DEV_SC1200 is not set
# CONFIG_BLK_DEV_PIIX is not set
# CONFIG_BLK_DEV_IT821X is not set
# CONFIG_BLK_DEV_NS87415 is not set
# CONFIG_BLK_DEV_PDC202XX_OLD is not set
# CONFIG_BLK_DEV_PDC202XX_NEW is not set
# CONFIG_BLK_DEV_SVWKS is not set
# CONFIG_BLK_DEV_SIIMAGE is not set
# CONFIG_BLK_DEV_SIS5513 is not set
# CONFIG_BLK_DEV_SLC90E66 is not set
# CONFIG_BLK_DEV_TRM290 is not set
# CONFIG_BLK_DEV_VIA82CXXX is not set
# CONFIG_IDE_ARM is not set
CONFIG_BLK_DEV_IDEDMA=y
# CONFIG_IDEDMA_IVB is not set
CONFIG_IDEDMA_AUTO=y
# CONFIG_BLK_DEV_HD is not set

#
# SCSI device support
#
# CONFIG_RAID_ATTRS is not set
CONFIG_SCSI=y
# CONFIG_SCSI_TGT is not set
# CONFIG_SCSI_NETLINK is not set
# CONFIG_SCSI_PROC_FS is not set

#
# SCSI support type (disk, tape, CD-ROM)
#
CONFIG_BLK_DEV_SD=y
# CONFIG_CHR_DEV_ST is not set
# CONFIG_CHR_DEV_OSST is not set
# CONFIG_BLK_DEV_SR is not set
# CONFIG_CHR_DEV_SG is not set
# CONFIG_CHR_DEV_SCH is not set

#
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
#
CONFIG_SCSI_MULTI_LUN=y
# CONFIG_SCSI_CONSTANTS is not set
CONFIG_SCSI_LOGGING=y
# CONFIG_SCSI_SCAN_ASYNC is not set

#
# SCSI Transports
#
CONFIG_SCSI_SPI_ATTRS=y
# CONFIG_SCSI_FC_ATTRS is not set
# CONFIG_SCSI_ISCSI_ATTRS is not set
# CONFIG_SCSI_SAS_ATTRS is not set
# CONFIG_SCSI_SAS_LIBSAS is not set

#
# SCSI low-level drivers
#
# CONFIG_ISCSI_TCP is not set
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_3W_9XXX is not set
# CONFIG_SCSI_ACARD is not set
# CONFIG_SCSI_AACRAID is not set
# CONFIG_SCSI_AIC7XXX is not set
# CONFIG_SCSI_AIC7XXX_OLD is not set
# CONFIG_SCSI_AIC79XX is not set
# CONFIG_SCSI_AIC94XX is not set
# CONFIG_SCSI_ARCMSR is not set
# CONFIG_MEGARAID_NEWGEN is not set
# CONFIG_MEGARAID_LEGACY is not set
# CONFIG_MEGARAID_SAS is not set
# CONFIG_SCSI_HPTIOP is not set
# CONFIG_SCSI_BUSLOGIC is not set
# CONFIG_SCSI_DMX3191D is not set
# CONFIG_SCSI_EATA is not set
# CONFIG_SCSI_FUTURE_DOMAIN is not set
# CONFIG_SCSI_GDTH is not set
CONFIG_SCSI_IPS=m
# CONFIG_SCSI_INITIO is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_STEX is not set
# CONFIG_SCSI_SYM53C8XX_2 is not set
# CONFIG_SCSI_QLOGIC_1280 is not set
# CONFIG_SCSI_QLA_FC is not set
# CONFIG_SCSI_QLA_ISCSI is not set
# CONFIG_SCSI_LPFC is not set
# CONFIG_SCSI_DC395x is not set
# CONFIG_SCSI_DC390T is not set
# CONFIG_SCSI_DEBUG is not set
# CONFIG_SCSI_SRP is not set

#
# Serial ATA (prod) and Parallel ATA (experimental) drivers
#
# CONFIG_ATA is not set

#
# Multi-device support (RAID and LVM)
#
# CONFIG_MD is not set

#
# Fusion MPT device support
#
CONFIG_FUSION=y
CONFIG_FUSION_SPI=y
# CONFIG_FUSION_FC is not set
# CONFIG_FUSION_SAS is not set
CONFIG_FUSION_MAX_SGE=40
# CONFIG_FUSION_CTL is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_IEEE1394 is not set

#
# I2O device support
#
# CONFIG_I2O is not set

#
# Network device support
#
CONFIG_NETDEVICES=y
# CONFIG_DUMMY is not set
# CONFIG_BONDING is not set
# CONFIG_EQUALIZER is not set
# CONFIG_TUN is not set

#
# ARCnet devices
#
# CONFIG_ARCNET is not set

#
# PHY device support
#
# CONFIG_PHYLIB is not set

#
# Ethernet (10 or 100Mbit)
#
CONFIG_NET_ETHERNET=y
CONFIG_MII=y
# CONFIG_HAPPYMEAL is not set
# CONFIG_SUNGEM is not set
# CONFIG_CASSINI is not set
# CONFIG_NET_VENDOR_3COM is not set

#
# Tulip family network device support
#
# CONFIG_NET_TULIP is not set
# CONFIG_HP100 is not set
CONFIG_NET_PCI=y
# CONFIG_PCNET32 is not set
CONFIG_AMD8111_ETH=y
# CONFIG_AMD8111E_NAPI is not set
# CONFIG_ADAPTEC_STARFIRE is not set
# CONFIG_B44 is not set
# CONFIG_FORCEDETH is not set
# CONFIG_DGRS is not set
# CONFIG_EEPRO100 is not set
# CONFIG_E100 is not set
# CONFIG_FEALNX is not set
# CONFIG_NATSEMI is not set
# CONFIG_NE2K_PCI is not set
CONFIG_8139CP=m
CONFIG_8139TOO=m
# CONFIG_8139TOO_PIO is not set
# CONFIG_8139TOO_TUNE_TWISTER is not set
# CONFIG_8139TOO_8129 is not set
# CONFIG_8139_OLD_RX_RESET is not set
# CONFIG_SIS900 is not set
# CONFIG_EPIC100 is not set
# CONFIG_SUNDANCE is not set
# CONFIG_VIA_RHINE is not set

#
# Ethernet (1000 Mbit)
#
# CONFIG_ACENIC is not set
# CONFIG_DL2K is not set
CONFIG_E1000=m
# CONFIG_E1000_NAPI is not set
# CONFIG_E1000_DISABLE_PACKET_SPLIT is not set
# CONFIG_NS83820 is not set
# CONFIG_HAMACHI is not set
# CONFIG_YELLOWFIN is not set
# CONFIG_R8169 is not set
# CONFIG_SIS190 is not set
# CONFIG_SKGE is not set
# CONFIG_SKY2 is not set
# CONFIG_SK98LIN is not set
# CONFIG_VIA_VELOCITY is not set
CONFIG_TIGON3=y
# CONFIG_BNX2 is not set
# CONFIG_QLA3XXX is not set

#
# Ethernet (10000 Mbit)
#
# CONFIG_CHELSIO_T1 is not set
# CONFIG_IXGB is not set
# CONFIG_S2IO is not set
# CONFIG_MYRI10GE is not set
# CONFIG_NETXEN_NIC is not set

#
# Token Ring devices
#
# CONFIG_TR is not set

#
# Wireless LAN (non-hamradio)
#
# CONFIG_NET_RADIO is not set

#
# Wan interfaces
#
# CONFIG_WAN is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
# CONFIG_PPP is not set
# CONFIG_SLIP is not set
# CONFIG_NET_FC is not set
# CONFIG_SHAPER is not set
# CONFIG_NETCONSOLE is not set
# CONFIG_NETPOLL is not set
# CONFIG_NET_POLL_CONTROLLER is not set

#
# ISDN subsystem
#
# CONFIG_ISDN is not set

#
# Telephony Support
#
# CONFIG_PHONE is not set

#
# Input device support
#
CONFIG_INPUT=y
# CONFIG_INPUT_FF_MEMLESS is not set

#
# Userland interfaces
#
CONFIG_INPUT_MOUSEDEV=y
CONFIG_INPUT_MOUSEDEV_PSAUX=y
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
# CONFIG_INPUT_JOYDEV is not set
# CONFIG_INPUT_TSDEV is not set
CONFIG_INPUT_EVDEV=y
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
CONFIG_INPUT_KEYBOARD=y
CONFIG_KEYBOARD_ATKBD=y
# CONFIG_KEYBOARD_SUNKBD is not set
# CONFIG_KEYBOARD_LKKBD is not set
# CONFIG_KEYBOARD_XTKBD is not set
# CONFIG_KEYBOARD_NEWTON is not set
# CONFIG_KEYBOARD_STOWAWAY is not set
CONFIG_INPUT_MOUSE=y
CONFIG_MOUSE_PS2=y
# CONFIG_MOUSE_SERIAL is not set
# CONFIG_MOUSE_VSXXXAA is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set

#
# Hardware I/O ports
#
CONFIG_SERIO=y
CONFIG_SERIO_I8042=y
# CONFIG_SERIO_SERPORT is not set
# CONFIG_SERIO_CT82C710 is not set
# CONFIG_SERIO_PCIPS2 is not set
CONFIG_SERIO_LIBPS2=y
# CONFIG_SERIO_RAW is not set
# CONFIG_GAMEPORT is not set

#
# Character devices
#
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
# CONFIG_VT_HW_CONSOLE_BINDING is not set
# CONFIG_SERIAL_NONSTANDARD is not set

#
# Serial drivers
#
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
# CONFIG_SERIAL_8250_EXTENDED is not set

#
# Non-8250 serial port support
#
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
# CONFIG_SERIAL_JSM is not set
CONFIG_UNIX98_PTYS=y
CONFIG_LEGACY_PTYS=y
CONFIG_LEGACY_PTY_COUNT=256

#
# IPMI
#
# CONFIG_IPMI_HANDLER is not set

#
# Watchdog Cards
#
# CONFIG_WATCHDOG is not set
CONFIG_HW_RANDOM=y
CONFIG_HW_RANDOM_INTEL=y
CONFIG_HW_RANDOM_AMD=y
CONFIG_HW_RANDOM_GEODE=y
# CONFIG_NVRAM is not set
CONFIG_RTC=y
# CONFIG_RTC_HISTOGRAM is not set
CONFIG_BLOCKER=y
CONFIG_LPPTEST=y
# CONFIG_DTLK is not set
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set
CONFIG_AGP=y
CONFIG_AGP_AMD64=y
# CONFIG_AGP_INTEL is not set
# CONFIG_AGP_SIS is not set
# CONFIG_AGP_VIA is not set
# CONFIG_DRM is not set
# CONFIG_MWAVE is not set
# CONFIG_PC8736x_GPIO is not set
CONFIG_RAW_DRIVER=y
CONFIG_MAX_RAW_DEVS=256
# CONFIG_HPET is not set
CONFIG_HANGCHECK_TIMER=y

#
# TPM devices
#
# CONFIG_TCG_TPM is not set
# CONFIG_TELCLOCK is not set

#
# I2C support
#
# CONFIG_I2C is not set

#
# SPI support
#
# CONFIG_SPI is not set
# CONFIG_SPI_MASTER is not set

#
# Dallas's 1-wire bus
#
# CONFIG_W1 is not set

#
# Hardware Monitoring support
#
CONFIG_HWMON=y
# CONFIG_HWMON_VID is not set
# CONFIG_SENSORS_ABITUGURU is not set
# CONFIG_SENSORS_K8TEMP is not set
# CONFIG_SENSORS_F71805F is not set
# CONFIG_SENSORS_PC87427 is not set
# CONFIG_SENSORS_VT1211 is not set
# CONFIG_SENSORS_HDAPS is not set
# CONFIG_HWMON_DEBUG_CHIP is not set

#
# Multimedia devices
#
# CONFIG_VIDEO_DEV is not set

#
# Digital Video Broadcasting Devices
#
# CONFIG_DVB is not set

#
# Graphics support
#
CONFIG_FIRMWARE_EDID=y
# CONFIG_FB is not set

#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
# CONFIG_VGACON_SOFT_SCROLLBACK is not set
# CONFIG_VIDEO_SELECT is not set
CONFIG_DUMMY_CONSOLE=y
# CONFIG_BACKLIGHT_LCD_SUPPORT is not set
CONFIG_BACKLIGHT_CLASS_DEVICE=y
CONFIG_BACKLIGHT_DEVICE=y

#
# Sound
#
CONFIG_SOUND=y

#
# Advanced Linux Sound Architecture
#
# CONFIG_SND is not set

#
# Open Sound System
#
CONFIG_SOUND_PRIME=y
# CONFIG_SOUND_BT878 is not set
# CONFIG_SOUND_ES1371 is not set
CONFIG_SOUND_ICH=y
# CONFIG_SOUND_TRIDENT is not set
# CONFIG_SOUND_MSNDCLAS is not set
# CONFIG_SOUND_MSNDPIN is not set
# CONFIG_SOUND_VIA82CXXX is not set
# CONFIG_SOUND_OSS is not set

#
# HID Devices
#
CONFIG_HID=y

#
# USB support
#
CONFIG_USB_ARCH_HAS_HCD=y
CONFIG_USB_ARCH_HAS_OHCI=y
CONFIG_USB_ARCH_HAS_EHCI=y
# CONFIG_USB is not set

#
# NOTE: USB_STORAGE enables SCSI, and 'SCSI disk support'
#

#
# USB Gadget Support
#
# CONFIG_USB_GADGET is not set

#
# MMC/SD Card support
#
# CONFIG_MMC is not set

#
# LED devices
#
# CONFIG_NEW_LEDS is not set

#
# LED drivers
#

#
# LED Triggers
#

#
# InfiniBand support
#
# CONFIG_INFINIBAND is not set

#
# EDAC - error detection and reporting (RAS) (EXPERIMENTAL)
#
# CONFIG_EDAC is not set

#
# Real Time Clock
#
# CONFIG_RTC_CLASS is not set

#
# DMA Engine support
#
# CONFIG_DMA_ENGINE is not set

#
# DMA Clients
#

#
# DMA Devices
#

#
# Virtualization
#
# CONFIG_KVM is not set

#
# Firmware Drivers
#
# CONFIG_EDD is not set
# CONFIG_DELL_RBU is not set
# CONFIG_DCDBAS is not set

#
# File systems
#
CONFIG_EXT2_FS=y
CONFIG_EXT2_FS_XATTR=y
CONFIG_EXT2_FS_POSIX_ACL=y
# CONFIG_EXT2_FS_SECURITY is not set
# CONFIG_EXT2_FS_XIP is not set
CONFIG_EXT3_FS=y
CONFIG_EXT3_FS_XATTR=y
CONFIG_EXT3_FS_POSIX_ACL=y
# CONFIG_EXT3_FS_SECURITY is not set
# CONFIG_EXT4DEV_FS is not set
CONFIG_JBD=y
# CONFIG_JBD_DEBUG is not set
CONFIG_FS_MBCACHE=y
CONFIG_REISERFS_FS=y
# CONFIG_REISERFS_CHECK is not set
# CONFIG_REISERFS_PROC_INFO is not set
# CONFIG_REISERFS_FS_XATTR is not set
CONFIG_JFS_FS=y
# CONFIG_JFS_POSIX_ACL is not set
# CONFIG_JFS_SECURITY is not set
# CONFIG_JFS_DEBUG is not set
# CONFIG_JFS_STATISTICS is not set
CONFIG_FS_POSIX_ACL=y
# CONFIG_XFS_FS is not set
# CONFIG_GFS2_FS is not set
# CONFIG_OCFS2_FS is not set
# CONFIG_MINIX_FS is not set
# CONFIG_ROMFS_FS is not set
CONFIG_INOTIFY=y
CONFIG_INOTIFY_USER=y
# CONFIG_QUOTA is not set
CONFIG_DNOTIFY=y
CONFIG_AUTOFS_FS=y
# CONFIG_AUTOFS4_FS is not set
# CONFIG_FUSE_FS is not set

#
# CD-ROM/DVD Filesystems
#
CONFIG_ISO9660_FS=y
# CONFIG_JOLIET is not set
# CONFIG_ZISOFS is not set
# CONFIG_UDF_FS is not set

#
# DOS/FAT/NT Filesystems
#
# CONFIG_MSDOS_FS is not set
# CONFIG_VFAT_FS is not set
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
CONFIG_PROC_KCORE=y
CONFIG_PROC_SYSCTL=y
CONFIG_SYSFS=y
CONFIG_TMPFS=y
# CONFIG_TMPFS_POSIX_ACL is not set
# CONFIG_HUGETLBFS is not set
# CONFIG_HUGETLB_PAGE is not set
CONFIG_RAMFS=y
# CONFIG_CONFIGFS_FS is not set

#
# Miscellaneous filesystems
#
# CONFIG_ADFS_FS is not set
# CONFIG_AFFS_FS is not set
# CONFIG_HFS_FS is not set
# CONFIG_HFSPLUS_FS is not set
# CONFIG_BEFS_FS is not set
# CONFIG_BFS_FS is not set
# CONFIG_EFS_FS is not set
# CONFIG_CRAMFS is not set
# CONFIG_VXFS_FS is not set
# CONFIG_HPFS_FS is not set
# CONFIG_QNX4FS_FS is not set
# CONFIG_SYSV_FS is not set
# CONFIG_UFS_FS is not set

#
# Network File Systems
#
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
# CONFIG_NFS_V3_ACL is not set
# CONFIG_NFS_V4 is not set
# CONFIG_NFS_DIRECTIO is not set
CONFIG_NFSD=y
CONFIG_NFSD_V3=y
# CONFIG_NFSD_V3_ACL is not set
# CONFIG_NFSD_V4 is not set
CONFIG_NFSD_TCP=y
CONFIG_LOCKD=y
CONFIG_LOCKD_V4=y
CONFIG_EXPORTFS=y
CONFIG_NFS_COMMON=y
CONFIG_SUNRPC=y
# CONFIG_RPCSEC_GSS_KRB5 is not set
# CONFIG_RPCSEC_GSS_SPKM3 is not set
# CONFIG_SMB_FS is not set
# CONFIG_CIFS is not set
# CONFIG_NCP_FS is not set
# CONFIG_CODA_FS is not set
# CONFIG_AFS_FS is not set
# CONFIG_9P_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y

#
# Native Language Support
#
CONFIG_NLS=y
CONFIG_NLS_DEFAULT="iso8859-1"
# CONFIG_NLS_CODEPAGE_437 is not set
# CONFIG_NLS_CODEPAGE_737 is not set
# CONFIG_NLS_CODEPAGE_775 is not set
# CONFIG_NLS_CODEPAGE_850 is not set
# CONFIG_NLS_CODEPAGE_852 is not set
# CONFIG_NLS_CODEPAGE_855 is not set
# CONFIG_NLS_CODEPAGE_857 is not set
# CONFIG_NLS_CODEPAGE_860 is not set
# CONFIG_NLS_CODEPAGE_861 is not set
# CONFIG_NLS_CODEPAGE_862 is not set
# CONFIG_NLS_CODEPAGE_863 is not set
# CONFIG_NLS_CODEPAGE_864 is not set
# CONFIG_NLS_CODEPAGE_865 is not set
# CONFIG_NLS_CODEPAGE_866 is not set
# CONFIG_NLS_CODEPAGE_869 is not set
# CONFIG_NLS_CODEPAGE_936 is not set
# CONFIG_NLS_CODEPAGE_950 is not set
# CONFIG_NLS_CODEPAGE_932 is not set
# CONFIG_NLS_CODEPAGE_949 is not set
# CONFIG_NLS_CODEPAGE_874 is not set
# CONFIG_NLS_ISO8859_8 is not set
# CONFIG_NLS_CODEPAGE_1250 is not set
# CONFIG_NLS_CODEPAGE_1251 is not set
# CONFIG_NLS_ASCII is not set
# CONFIG_NLS_ISO8859_1 is not set
# CONFIG_NLS_ISO8859_2 is not set
# CONFIG_NLS_ISO8859_3 is not set
# CONFIG_NLS_ISO8859_4 is not set
# CONFIG_NLS_ISO8859_5 is not set
# CONFIG_NLS_ISO8859_6 is not set
# CONFIG_NLS_ISO8859_7 is not set
# CONFIG_NLS_ISO8859_9 is not set
# CONFIG_NLS_ISO8859_13 is not set
# CONFIG_NLS_ISO8859_14 is not set
# CONFIG_NLS_ISO8859_15 is not set
# CONFIG_NLS_KOI8_R is not set
# CONFIG_NLS_KOI8_U is not set
# CONFIG_NLS_UTF8 is not set

#
# Distributed Lock Manager
#
# CONFIG_DLM is not set

#
# Instrumentation Support
#
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
# CONFIG_KPROBES is not set

#
# Kernel hacking
#
CONFIG_TRACE_IRQFLAGS_SUPPORT=y
# CONFIG_PRINTK_TIME is not set
CONFIG_ENABLE_MUST_CHECK=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_UNUSED_SYMBOLS=y
# CONFIG_DEBUG_FS is not set
# CONFIG_HEADERS_CHECK is not set
CONFIG_DEBUG_KERNEL=y
CONFIG_LOG_BUF_SHIFT=18
CONFIG_DETECT_SOFTLOCKUP=y
# CONFIG_SCHEDSTATS is not set
# CONFIG_TIMER_STATS is not set
# CONFIG_DEBUG_SLAB is not set
CONFIG_DEBUG_PREEMPT=y
# CONFIG_DEBUG_RT_MUTEXES is not set
# CONFIG_RT_MUTEX_TESTER is not set
# CONFIG_DEBUG_SPINLOCK is not set
# CONFIG_DEBUG_RWSEMS is not set
# CONFIG_DEBUG_LOCK_ALLOC is not set
# CONFIG_PROVE_LOCKING is not set
# CONFIG_DEBUG_SPINLOCK_SLEEP is not set
# CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
CONFIG_PREEMPT_TRACE=y
# CONFIG_EVENT_TRACE is not set
# CONFIG_FUNCTION_TRACE is not set
CONFIG_WAKEUP_TIMING=y
# CONFIG_LATENCY_TRACE is not set
# CONFIG_CRITICAL_PREEMPT_TIMING is not set
# CONFIG_CRITICAL_IRQSOFF_TIMING is not set
# CONFIG_WAKEUP_LATENCY_HIST is not set
CONFIG_LATENCY_TIMING=y
# CONFIG_DEBUG_KOBJECT is not set
CONFIG_DEBUG_BUGVERBOSE=y
# CONFIG_DEBUG_INFO is not set
# CONFIG_DEBUG_VM is not set
# CONFIG_DEBUG_LIST is not set
# CONFIG_FRAME_POINTER is not set
# CONFIG_UNWIND_INFO is not set
CONFIG_FORCED_INLINING=y
CONFIG_RCU_TORTURE_TEST=m
# CONFIG_DEBUG_RODATA is not set
CONFIG_IOMMU_DEBUG=y
CONFIG_IOMMU_LEAK=y
# CONFIG_DEBUG_STACKOVERFLOW is not set
# CONFIG_DEBUG_STACK_USAGE is not set

#
# Security options
#
# CONFIG_KEYS is not set
# CONFIG_SECURITY is not set

#
# Cryptographic options
#
# CONFIG_CRYPTO is not set

#
# Library routines
#
CONFIG_BITREVERSE=y
# CONFIG_CRC_CCITT is not set
# CONFIG_CRC16 is not set
CONFIG_CRC32=y
# CONFIG_LIBCRC32C is not set
CONFIG_PLIST=y
CONFIG_IOMAP_COPY=y

Re: BUG in 2.6.20-rt8

[Paul E. McKenney]

On Sat, Feb 24, 2007 at 09:02:12PM -0800, Paul E. McKenney wrote:
> Hello!
> 
> I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz Opteron
> box.  The machine continued to run a few rounds of kernbench and LTP.
> Looks a bit scary -- a tasklet was "stolen" from __tasklet_action().
> 
> Thoughts?  In the meantime, kicking it off again to see if it repeats.

Not reproducible.  :-/

						Thanx, Paul

> BUG: at kernel/softirq.c:559 __tasklet_action()
> 
> Call Trace:
>  [<ffffffff8022ec1b>] __tasklet_action+0xdb/0x120
>  [<ffffffff8022ee12>] ksoftirqd+0xf3/0x179
>  [<ffffffff8022ed1f>] ksoftirqd+0x0/0x179
>  [<ffffffff8023be23>] kthread+0xc8/0xf1
>  [<ffffffff8020a708>] child_rip+0xa/0x12
>  [<ffffffff8023bf27>] kthread_create+0x6e/0x159
>  [<ffffffff8023bd5b>] kthread+0x0/0xf1
>  [<ffffffff8020a6fe>] child_rip+0x0/0x12
> 
> ---------------------------
> | preempt count: 00000000 ]
> | 0-level deep critical section nesting:
> ----------------------------------------
> 
> Config:
> 
> #
> # Automatically generated make config: don't edit
> # Linux kernel version: 2.6.20-rt8-autokern1
> # Sat Feb 24 17:05:11 2007
> #
> CONFIG_X86_64=y
> CONFIG_64BIT=y
> CONFIG_X86=y
> CONFIG_GENERIC_TIME=y
> CONFIG_GENERIC_CLOCKEVENTS=y
> CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
> CONFIG_GENERIC_TIME_VSYSCALL=y
> CONFIG_ZONE_DMA32=y
> CONFIG_LOCKDEP_SUPPORT=y
> CONFIG_STACKTRACE_SUPPORT=y
> CONFIG_SEMAPHORE_SLEEPERS=y
> CONFIG_MMU=y
> CONFIG_GENERIC_HWEIGHT=y
> CONFIG_GENERIC_CALIBRATE_DELAY=y
> CONFIG_X86_CMPXCHG=y
> CONFIG_EARLY_PRINTK=y
> CONFIG_GENERIC_ISA_DMA=y
> CONFIG_GENERIC_IOMAP=y
> CONFIG_ARCH_MAY_HAVE_PC_FDC=y
> CONFIG_ARCH_POPULATES_NODE_MAP=y
> CONFIG_DMI=y
> CONFIG_AUDIT_ARCH=y
> CONFIG_GENERIC_BUG=y
> # CONFIG_ARCH_HAS_ILOG2_U32 is not set
> # CONFIG_ARCH_HAS_ILOG2_U64 is not set
> CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"
> 
> #
> # Code maturity level options
> #
> CONFIG_EXPERIMENTAL=y
> CONFIG_LOCK_KERNEL=y
> CONFIG_INIT_ENV_ARG_LIMIT=32
> 
> #
> # General setup
> #
> CONFIG_LOCALVERSION=""
> CONFIG_LOCALVERSION_AUTO=y
> CONFIG_SWAP=y
> CONFIG_SYSVIPC=y
> # CONFIG_IPC_NS is not set
> # CONFIG_POSIX_MQUEUE is not set
> # CONFIG_BSD_PROCESS_ACCT is not set
> # CONFIG_TASKSTATS is not set
> # CONFIG_UTS_NS is not set
> # CONFIG_AUDIT is not set
> # CONFIG_IKCONFIG is not set
> # CONFIG_CPUSETS is not set
> CONFIG_SYSFS_DEPRECATED=y
> # CONFIG_RELAY is not set
> CONFIG_INITRAMFS_SOURCE=""
> CONFIG_CC_OPTIMIZE_FOR_SIZE=y
> CONFIG_SYSCTL=y
> # CONFIG_EMBEDDED is not set
> CONFIG_UID16=y
> CONFIG_SYSCTL_SYSCALL=y
> CONFIG_KALLSYMS=y
> # CONFIG_KALLSYMS_ALL is not set
> # CONFIG_KALLSYMS_EXTRA_PASS is not set
> CONFIG_HOTPLUG=y
> CONFIG_PRINTK=y
> CONFIG_BUG=y
> CONFIG_ELF_CORE=y
> CONFIG_BASE_FULL=y
> CONFIG_FUTEX=y
> CONFIG_EPOLL=y
> CONFIG_SHMEM=y
> CONFIG_SLAB=y
> CONFIG_VM_EVENT_COUNTERS=y
> CONFIG_RT_MUTEXES=y
> # CONFIG_TINY_SHMEM is not set
> CONFIG_BASE_SMALL=0
> # CONFIG_SLOB is not set
> 
> #
> # Loadable module support
> #
> CONFIG_MODULES=y
> CONFIG_MODULE_UNLOAD=y
> CONFIG_MODULE_FORCE_UNLOAD=y
> # CONFIG_MODVERSIONS is not set
> # CONFIG_MODULE_SRCVERSION_ALL is not set
> # CONFIG_KMOD is not set
> CONFIG_STOP_MACHINE=y
> 
> #
> # Block layer
> #
> CONFIG_BLOCK=y
> # CONFIG_BLK_DEV_IO_TRACE is not set
> 
> #
> # IO Schedulers
> #
> CONFIG_IOSCHED_NOOP=y
> CONFIG_IOSCHED_AS=y
> CONFIG_IOSCHED_DEADLINE=y
> CONFIG_IOSCHED_CFQ=y
> # CONFIG_DEFAULT_AS is not set
> # CONFIG_DEFAULT_DEADLINE is not set
> CONFIG_DEFAULT_CFQ=y
> # CONFIG_DEFAULT_NOOP is not set
> CONFIG_DEFAULT_IOSCHED="cfq"
> 
> #
> # Processor type and features
> #
> CONFIG_X86_PC=y
> # CONFIG_X86_VSMP is not set
> CONFIG_MK8=y
> # CONFIG_MPSC is not set
> # CONFIG_MCORE2 is not set
> # CONFIG_GENERIC_CPU is not set
> CONFIG_X86_L1_CACHE_BYTES=64
> CONFIG_X86_L1_CACHE_SHIFT=6
> CONFIG_X86_INTERNODE_CACHE_BYTES=64
> CONFIG_X86_TSC=y
> CONFIG_X86_GOOD_APIC=y
> # CONFIG_MICROCODE is not set
> CONFIG_X86_MSR=y
> CONFIG_X86_CPUID=y
> CONFIG_X86_IO_APIC=y
> CONFIG_X86_LOCAL_APIC=y
> CONFIG_MTRR=y
> CONFIG_SMP=y
> # CONFIG_SCHED_SMT is not set
> CONFIG_SCHED_MC=y
> # CONFIG_TICK_ONESHOT is not set
> # CONFIG_NO_HZ is not set
> # CONFIG_HIGH_RES_TIMERS is not set
> # CONFIG_PREEMPT_NONE is not set
> # CONFIG_PREEMPT_VOLUNTARY is not set
> # CONFIG_PREEMPT_DESKTOP is not set
> CONFIG_PREEMPT_RT=y
> CONFIG_PREEMPT=y
> CONFIG_PREEMPT_SOFTIRQS=y
> CONFIG_PREEMPT_HARDIRQS=y
> CONFIG_PREEMPT_BKL=y
> # CONFIG_CLASSIC_RCU is not set
> CONFIG_PREEMPT_RCU=y
> # CONFIG_RCU_TRACE is not set
> CONFIG_NUMA=y
> CONFIG_RWSEM_GENERIC_SPINLOCK=y
> CONFIG_K8_NUMA=y
> CONFIG_NODES_SHIFT=6
> CONFIG_X86_64_ACPI_NUMA=y
> # CONFIG_NUMA_EMU is not set
> CONFIG_ARCH_DISCONTIGMEM_ENABLE=y
> CONFIG_ARCH_DISCONTIGMEM_DEFAULT=y
> CONFIG_ARCH_SPARSEMEM_ENABLE=y
> CONFIG_SELECT_MEMORY_MODEL=y
> # CONFIG_FLATMEM_MANUAL is not set
> CONFIG_DISCONTIGMEM_MANUAL=y
> # CONFIG_SPARSEMEM_MANUAL is not set
> CONFIG_DISCONTIGMEM=y
> CONFIG_FLAT_NODE_MEM_MAP=y
> CONFIG_NEED_MULTIPLE_NODES=y
> # CONFIG_SPARSEMEM_STATIC is not set
> # CONFIG_MEMORY_HOTPLUG is not set
> CONFIG_SPLIT_PTLOCK_CPUS=4
> CONFIG_MIGRATION=y
> CONFIG_RESOURCES_64BIT=y
> CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID=y
> CONFIG_OUT_OF_LINE_PFN_TO_PAGE=y
> CONFIG_NR_CPUS=8
> # CONFIG_HOTPLUG_CPU is not set
> CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
> CONFIG_HPET_TIMER=y
> # CONFIG_HPET_EMULATE_RTC is not set
> CONFIG_IOMMU=y
> # CONFIG_CALGARY_IOMMU is not set
> CONFIG_SWIOTLB=y
> CONFIG_X86_MCE=y
> CONFIG_X86_MCE_INTEL=y
> CONFIG_X86_MCE_AMD=y
> # CONFIG_KEXEC is not set
> # CONFIG_CRASH_DUMP is not set
> CONFIG_PHYSICAL_START=0x200000
> CONFIG_SECCOMP=y
> # CONFIG_CC_STACKPROTECTOR is not set
> # CONFIG_HZ_100 is not set
> CONFIG_HZ_250=y
> # CONFIG_HZ_300 is not set
> # CONFIG_HZ_1000 is not set
> CONFIG_HZ=250
> # CONFIG_REORDER is not set
> CONFIG_K8_NB=y
> CONFIG_GENERIC_HARDIRQS=y
> CONFIG_GENERIC_IRQ_PROBE=y
> CONFIG_ISA_DMA_API=y
> CONFIG_GENERIC_PENDING_IRQ=y
> 
> #
> # Power management options
> #
> CONFIG_PM=y
> # CONFIG_PM_LEGACY is not set
> # CONFIG_PM_DEBUG is not set
> # CONFIG_PM_SYSFS_DEPRECATED is not set
> 
> #
> # ACPI (Advanced Configuration and Power Interface) Support
> #
> CONFIG_ACPI=y
> CONFIG_ACPI_AC=y
> CONFIG_ACPI_BATTERY=y
> CONFIG_ACPI_BUTTON=y
> CONFIG_ACPI_VIDEO=m
> # CONFIG_ACPI_HOTKEY is not set
> CONFIG_ACPI_FAN=y
> # CONFIG_ACPI_DOCK is not set
> CONFIG_ACPI_PROCESSOR=y
> CONFIG_ACPI_THERMAL=y
> CONFIG_ACPI_NUMA=y
> # CONFIG_ACPI_ASUS is not set
> CONFIG_ACPI_IBM=m
> # CONFIG_ACPI_IBM_DOCK is not set
> CONFIG_ACPI_TOSHIBA=y
> CONFIG_ACPI_BLACKLIST_YEAR=0
> CONFIG_ACPI_DEBUG=y
> CONFIG_ACPI_EC=y
> CONFIG_ACPI_POWER=y
> CONFIG_ACPI_SYSTEM=y
> CONFIG_X86_PM_TIMER=y
> # CONFIG_ACPI_CONTAINER is not set
> 
> #
> # CPU Frequency scaling
> #
> # CONFIG_CPU_FREQ is not set
> 
> #
> # Bus options (PCI etc.)
> #
> CONFIG_PCI=y
> CONFIG_PCI_DIRECT=y
> # CONFIG_PCI_MMCONFIG is not set
> # CONFIG_PCIEPORTBUS is not set
> # CONFIG_PCI_MSI is not set
> # CONFIG_PCI_DEBUG is not set
> CONFIG_HT_IRQ=y
> 
> #
> # PCCARD (PCMCIA/CardBus) support
> #
> # CONFIG_PCCARD is not set
> 
> #
> # PCI Hotplug Support
> #
> # CONFIG_HOTPLUG_PCI is not set
> 
> #
> # Executable file formats / Emulations
> #
> CONFIG_BINFMT_ELF=y
> # CONFIG_BINFMT_MISC is not set
> CONFIG_IA32_EMULATION=y
> # CONFIG_IA32_AOUT is not set
> CONFIG_COMPAT=y
> CONFIG_SYSVIPC_COMPAT=y
> 
> #
> # Networking
> #
> CONFIG_NET=y
> 
> #
> # Networking options
> #
> # CONFIG_NETDEBUG is not set
> CONFIG_PACKET=y
> # CONFIG_PACKET_MMAP is not set
> CONFIG_UNIX=y
> CONFIG_XFRM=y
> # CONFIG_XFRM_USER is not set
> # CONFIG_XFRM_SUB_POLICY is not set
> # CONFIG_NET_KEY is not set
> CONFIG_INET=y
> CONFIG_IP_MULTICAST=y
> # CONFIG_IP_ADVANCED_ROUTER is not set
> CONFIG_IP_FIB_HASH=y
> # CONFIG_IP_PNP is not set
> # CONFIG_NET_IPIP is not set
> # CONFIG_NET_IPGRE is not set
> # CONFIG_IP_MROUTE is not set
> # CONFIG_ARPD is not set
> # CONFIG_SYN_COOKIES is not set
> # CONFIG_INET_AH is not set
> # CONFIG_INET_ESP is not set
> # CONFIG_INET_IPCOMP is not set
> # CONFIG_INET_XFRM_TUNNEL is not set
> # CONFIG_INET_TUNNEL is not set
> CONFIG_INET_XFRM_MODE_TRANSPORT=y
> CONFIG_INET_XFRM_MODE_TUNNEL=y
> CONFIG_INET_XFRM_MODE_BEET=y
> CONFIG_INET_DIAG=y
> CONFIG_INET_TCP_DIAG=y
> # CONFIG_TCP_CONG_ADVANCED is not set
> CONFIG_TCP_CONG_CUBIC=y
> CONFIG_DEFAULT_TCP_CONG="cubic"
> # CONFIG_TCP_MD5SIG is not set
> # CONFIG_IPV6 is not set
> # CONFIG_INET6_XFRM_TUNNEL is not set
> # CONFIG_INET6_TUNNEL is not set
> # CONFIG_NETWORK_SECMARK is not set
> # CONFIG_NETFILTER is not set
> 
> #
> # DCCP Configuration (EXPERIMENTAL)
> #
> # CONFIG_IP_DCCP is not set
> 
> #
> # SCTP Configuration (EXPERIMENTAL)
> #
> # CONFIG_IP_SCTP is not set
> 
> #
> # TIPC Configuration (EXPERIMENTAL)
> #
> # CONFIG_TIPC is not set
> # CONFIG_ATM is not set
> # CONFIG_BRIDGE is not set
> # CONFIG_VLAN_8021Q is not set
> # CONFIG_DECNET is not set
> # CONFIG_LLC2 is not set
> # CONFIG_IPX is not set
> # CONFIG_ATALK is not set
> # CONFIG_X25 is not set
> # CONFIG_LAPB is not set
> # CONFIG_ECONET is not set
> # CONFIG_WAN_ROUTER is not set
> 
> #
> # QoS and/or fair queueing
> #
> # CONFIG_NET_SCHED is not set
> 
> #
> # Network testing
> #
> # CONFIG_NET_PKTGEN is not set
> # CONFIG_HAMRADIO is not set
> # CONFIG_IRDA is not set
> # CONFIG_BT is not set
> # CONFIG_IEEE80211 is not set
> 
> #
> # Device Drivers
> #
> 
> #
> # Generic Driver Options
> #
> CONFIG_STANDALONE=y
> CONFIG_PREVENT_FIRMWARE_BUILD=y
> # CONFIG_FW_LOADER is not set
> # CONFIG_DEBUG_DRIVER is not set
> # CONFIG_SYS_HYPERVISOR is not set
> 
> #
> # Connector - unified userspace <-> kernelspace linker
> #
> # CONFIG_CONNECTOR is not set
> 
> #
> # Memory Technology Devices (MTD)
> #
> # CONFIG_MTD is not set
> 
> #
> # Parallel port support
> #
> # CONFIG_PARPORT is not set
> 
> #
> # Plug and Play support
> #
> # CONFIG_PNP is not set
> 
> #
> # Block devices
> #
> # CONFIG_BLK_DEV_FD is not set
> # CONFIG_BLK_CPQ_DA is not set
> # CONFIG_BLK_CPQ_CISS_DA is not set
> # CONFIG_BLK_DEV_DAC960 is not set
> # CONFIG_BLK_DEV_UMEM is not set
> # CONFIG_BLK_DEV_COW_COMMON is not set
> CONFIG_BLK_DEV_LOOP=y
> # CONFIG_BLK_DEV_CRYPTOLOOP is not set
> # CONFIG_BLK_DEV_NBD is not set
> # CONFIG_BLK_DEV_SX8 is not set
> CONFIG_BLK_DEV_RAM=y
> CONFIG_BLK_DEV_RAM_COUNT=16
> CONFIG_BLK_DEV_RAM_SIZE=4096
> CONFIG_BLK_DEV_RAM_BLOCKSIZE=1024
> CONFIG_BLK_DEV_INITRD=y
> # CONFIG_CDROM_PKTCDVD is not set
> # CONFIG_ATA_OVER_ETH is not set
> 
> #
> # Misc devices
> #
> # CONFIG_IBM_ASM is not set
> # CONFIG_SGI_IOC4 is not set
> # CONFIG_TIFM_CORE is not set
> # CONFIG_MSI_LAPTOP is not set
> 
> #
> # ATA/ATAPI/MFM/RLL support
> #
> CONFIG_IDE=y
> CONFIG_BLK_DEV_IDE=y
> 
> #
> # Please see Documentation/ide.txt for help/info on IDE drives
> #
> # CONFIG_BLK_DEV_IDE_SATA is not set
> # CONFIG_BLK_DEV_HD_IDE is not set
> CONFIG_BLK_DEV_IDEDISK=y
> CONFIG_IDEDISK_MULTI_MODE=y
> CONFIG_BLK_DEV_IDECD=y
> # CONFIG_BLK_DEV_IDETAPE is not set
> # CONFIG_BLK_DEV_IDEFLOPPY is not set
> # CONFIG_BLK_DEV_IDESCSI is not set
> # CONFIG_IDE_TASK_IOCTL is not set
> 
> #
> # IDE chipset support/bugfixes
> #
> CONFIG_IDE_GENERIC=y
> # CONFIG_BLK_DEV_CMD640 is not set
> CONFIG_BLK_DEV_IDEPCI=y
> # CONFIG_IDEPCI_SHARE_IRQ is not set
> # CONFIG_BLK_DEV_OFFBOARD is not set
> # CONFIG_BLK_DEV_GENERIC is not set
> # CONFIG_BLK_DEV_OPTI621 is not set
> # CONFIG_BLK_DEV_RZ1000 is not set
> CONFIG_BLK_DEV_IDEDMA_PCI=y
> # CONFIG_BLK_DEV_IDEDMA_FORCED is not set
> CONFIG_IDEDMA_PCI_AUTO=y
> # CONFIG_IDEDMA_ONLYDISK is not set
> # CONFIG_BLK_DEV_AEC62XX is not set
> # CONFIG_BLK_DEV_ALI15X3 is not set
> CONFIG_BLK_DEV_AMD74XX=y
> # CONFIG_BLK_DEV_ATIIXP is not set
> # CONFIG_BLK_DEV_CMD64X is not set
> # CONFIG_BLK_DEV_TRIFLEX is not set
> # CONFIG_BLK_DEV_CY82C693 is not set
> # CONFIG_BLK_DEV_CS5520 is not set
> # CONFIG_BLK_DEV_CS5530 is not set
> # CONFIG_BLK_DEV_HPT34X is not set
> # CONFIG_BLK_DEV_HPT366 is not set
> # CONFIG_BLK_DEV_JMICRON is not set
> # CONFIG_BLK_DEV_SC1200 is not set
> # CONFIG_BLK_DEV_PIIX is not set
> # CONFIG_BLK_DEV_IT821X is not set
> # CONFIG_BLK_DEV_NS87415 is not set
> # CONFIG_BLK_DEV_PDC202XX_OLD is not set
> # CONFIG_BLK_DEV_PDC202XX_NEW is not set
> # CONFIG_BLK_DEV_SVWKS is not set
> # CONFIG_BLK_DEV_SIIMAGE is not set
> # CONFIG_BLK_DEV_SIS5513 is not set
> # CONFIG_BLK_DEV_SLC90E66 is not set
> # CONFIG_BLK_DEV_TRM290 is not set
> # CONFIG_BLK_DEV_VIA82CXXX is not set
> # CONFIG_IDE_ARM is not set
> CONFIG_BLK_DEV_IDEDMA=y
> # CONFIG_IDEDMA_IVB is not set
> CONFIG_IDEDMA_AUTO=y
> # CONFIG_BLK_DEV_HD is not set
> 
> #
> # SCSI device support
> #
> # CONFIG_RAID_ATTRS is not set
> CONFIG_SCSI=y
> # CONFIG_SCSI_TGT is not set
> # CONFIG_SCSI_NETLINK is not set
> # CONFIG_SCSI_PROC_FS is not set
> 
> #
> # SCSI support type (disk, tape, CD-ROM)
> #
> CONFIG_BLK_DEV_SD=y
> # CONFIG_CHR_DEV_ST is not set
> # CONFIG_CHR_DEV_OSST is not set
> # CONFIG_BLK_DEV_SR is not set
> # CONFIG_CHR_DEV_SG is not set
> # CONFIG_CHR_DEV_SCH is not set
> 
> #
> # Some SCSI devices (e.g. CD jukebox) support multiple LUNs
> #
> CONFIG_SCSI_MULTI_LUN=y
> # CONFIG_SCSI_CONSTANTS is not set
> CONFIG_SCSI_LOGGING=y
> # CONFIG_SCSI_SCAN_ASYNC is not set
> 
> #
> # SCSI Transports
> #
> CONFIG_SCSI_SPI_ATTRS=y
> # CONFIG_SCSI_FC_ATTRS is not set
> # CONFIG_SCSI_ISCSI_ATTRS is not set
> # CONFIG_SCSI_SAS_ATTRS is not set
> # CONFIG_SCSI_SAS_LIBSAS is not set
> 
> #
> # SCSI low-level drivers
> #
> # CONFIG_ISCSI_TCP is not set
> # CONFIG_BLK_DEV_3W_XXXX_RAID is not set
> # CONFIG_SCSI_3W_9XXX is not set
> # CONFIG_SCSI_ACARD is not set
> # CONFIG_SCSI_AACRAID is not set
> # CONFIG_SCSI_AIC7XXX is not set
> # CONFIG_SCSI_AIC7XXX_OLD is not set
> # CONFIG_SCSI_AIC79XX is not set
> # CONFIG_SCSI_AIC94XX is not set
> # CONFIG_SCSI_ARCMSR is not set
> # CONFIG_MEGARAID_NEWGEN is not set
> # CONFIG_MEGARAID_LEGACY is not set
> # CONFIG_MEGARAID_SAS is not set
> # CONFIG_SCSI_HPTIOP is not set
> # CONFIG_SCSI_BUSLOGIC is not set
> # CONFIG_SCSI_DMX3191D is not set
> # CONFIG_SCSI_EATA is not set
> # CONFIG_SCSI_FUTURE_DOMAIN is not set
> # CONFIG_SCSI_GDTH is not set
> CONFIG_SCSI_IPS=m
> # CONFIG_SCSI_INITIO is not set
> # CONFIG_SCSI_INIA100 is not set
> # CONFIG_SCSI_STEX is not set
> # CONFIG_SCSI_SYM53C8XX_2 is not set
> # CONFIG_SCSI_QLOGIC_1280 is not set
> # CONFIG_SCSI_QLA_FC is not set
> # CONFIG_SCSI_QLA_ISCSI is not set
> # CONFIG_SCSI_LPFC is not set
> # CONFIG_SCSI_DC395x is not set
> # CONFIG_SCSI_DC390T is not set
> # CONFIG_SCSI_DEBUG is not set
> # CONFIG_SCSI_SRP is not set
> 
> #
> # Serial ATA (prod) and Parallel ATA (experimental) drivers
> #
> # CONFIG_ATA is not set
> 
> #
> # Multi-device support (RAID and LVM)
> #
> # CONFIG_MD is not set
> 
> #
> # Fusion MPT device support
> #
> CONFIG_FUSION=y
> CONFIG_FUSION_SPI=y
> # CONFIG_FUSION_FC is not set
> # CONFIG_FUSION_SAS is not set
> CONFIG_FUSION_MAX_SGE=40
> # CONFIG_FUSION_CTL is not set
> 
> #
> # IEEE 1394 (FireWire) support
> #
> # CONFIG_IEEE1394 is not set
> 
> #
> # I2O device support
> #
> # CONFIG_I2O is not set
> 
> #
> # Network device support
> #
> CONFIG_NETDEVICES=y
> # CONFIG_DUMMY is not set
> # CONFIG_BONDING is not set
> # CONFIG_EQUALIZER is not set
> # CONFIG_TUN is not set
> 
> #
> # ARCnet devices
> #
> # CONFIG_ARCNET is not set
> 
> #
> # PHY device support
> #
> # CONFIG_PHYLIB is not set
> 
> #
> # Ethernet (10 or 100Mbit)
> #
> CONFIG_NET_ETHERNET=y
> CONFIG_MII=y
> # CONFIG_HAPPYMEAL is not set
> # CONFIG_SUNGEM is not set
> # CONFIG_CASSINI is not set
> # CONFIG_NET_VENDOR_3COM is not set
> 
> #
> # Tulip family network device support
> #
> # CONFIG_NET_TULIP is not set
> # CONFIG_HP100 is not set
> CONFIG_NET_PCI=y
> # CONFIG_PCNET32 is not set
> CONFIG_AMD8111_ETH=y
> # CONFIG_AMD8111E_NAPI is not set
> # CONFIG_ADAPTEC_STARFIRE is not set
> # CONFIG_B44 is not set
> # CONFIG_FORCEDETH is not set
> # CONFIG_DGRS is not set
> # CONFIG_EEPRO100 is not set
> # CONFIG_E100 is not set
> # CONFIG_FEALNX is not set
> # CONFIG_NATSEMI is not set
> # CONFIG_NE2K_PCI is not set
> CONFIG_8139CP=m
> CONFIG_8139TOO=m
> # CONFIG_8139TOO_PIO is not set
> # CONFIG_8139TOO_TUNE_TWISTER is not set
> # CONFIG_8139TOO_8129 is not set
> # CONFIG_8139_OLD_RX_RESET is not set
> # CONFIG_SIS900 is not set
> # CONFIG_EPIC100 is not set
> # CONFIG_SUNDANCE is not set
> # CONFIG_VIA_RHINE is not set
> 
> #
> # Ethernet (1000 Mbit)
> #
> # CONFIG_ACENIC is not set
> # CONFIG_DL2K is not set
> CONFIG_E1000=m
> # CONFIG_E1000_NAPI is not set
> # CONFIG_E1000_DISABLE_PACKET_SPLIT is not set
> # CONFIG_NS83820 is not set
> # CONFIG_HAMACHI is not set
> # CONFIG_YELLOWFIN is not set
> # CONFIG_R8169 is not set
> # CONFIG_SIS190 is not set
> # CONFIG_SKGE is not set
> # CONFIG_SKY2 is not set
> # CONFIG_SK98LIN is not set
> # CONFIG_VIA_VELOCITY is not set
> CONFIG_TIGON3=y
> # CONFIG_BNX2 is not set
> # CONFIG_QLA3XXX is not set
> 
> #
> # Ethernet (10000 Mbit)
> #
> # CONFIG_CHELSIO_T1 is not set
> # CONFIG_IXGB is not set
> # CONFIG_S2IO is not set
> # CONFIG_MYRI10GE is not set
> # CONFIG_NETXEN_NIC is not set
> 
> #
> # Token Ring devices
> #
> # CONFIG_TR is not set
> 
> #
> # Wireless LAN (non-hamradio)
> #
> # CONFIG_NET_RADIO is not set
> 
> #
> # Wan interfaces
> #
> # CONFIG_WAN is not set
> # CONFIG_FDDI is not set
> # CONFIG_HIPPI is not set
> # CONFIG_PPP is not set
> # CONFIG_SLIP is not set
> # CONFIG_NET_FC is not set
> # CONFIG_SHAPER is not set
> # CONFIG_NETCONSOLE is not set
> # CONFIG_NETPOLL is not set
> # CONFIG_NET_POLL_CONTROLLER is not set
> 
> #
> # ISDN subsystem
> #
> # CONFIG_ISDN is not set
> 
> #
> # Telephony Support
> #
> # CONFIG_PHONE is not set
> 
> #
> # Input device support
> #
> CONFIG_INPUT=y
> # CONFIG_INPUT_FF_MEMLESS is not set
> 
> #
> # Userland interfaces
> #
> CONFIG_INPUT_MOUSEDEV=y
> CONFIG_INPUT_MOUSEDEV_PSAUX=y
> CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
> CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
> # CONFIG_INPUT_JOYDEV is not set
> # CONFIG_INPUT_TSDEV is not set
> CONFIG_INPUT_EVDEV=y
> # CONFIG_INPUT_EVBUG is not set
> 
> #
> # Input Device Drivers
> #
> CONFIG_INPUT_KEYBOARD=y
> CONFIG_KEYBOARD_ATKBD=y
> # CONFIG_KEYBOARD_SUNKBD is not set
> # CONFIG_KEYBOARD_LKKBD is not set
> # CONFIG_KEYBOARD_XTKBD is not set
> # CONFIG_KEYBOARD_NEWTON is not set
> # CONFIG_KEYBOARD_STOWAWAY is not set
> CONFIG_INPUT_MOUSE=y
> CONFIG_MOUSE_PS2=y
> # CONFIG_MOUSE_SERIAL is not set
> # CONFIG_MOUSE_VSXXXAA is not set
> # CONFIG_INPUT_JOYSTICK is not set
> # CONFIG_INPUT_TOUCHSCREEN is not set
> # CONFIG_INPUT_MISC is not set
> 
> #
> # Hardware I/O ports
> #
> CONFIG_SERIO=y
> CONFIG_SERIO_I8042=y
> # CONFIG_SERIO_SERPORT is not set
> # CONFIG_SERIO_CT82C710 is not set
> # CONFIG_SERIO_PCIPS2 is not set
> CONFIG_SERIO_LIBPS2=y
> # CONFIG_SERIO_RAW is not set
> # CONFIG_GAMEPORT is not set
> 
> #
> # Character devices
> #
> CONFIG_VT=y
> CONFIG_VT_CONSOLE=y
> CONFIG_HW_CONSOLE=y
> # CONFIG_VT_HW_CONSOLE_BINDING is not set
> # CONFIG_SERIAL_NONSTANDARD is not set
> 
> #
> # Serial drivers
> #
> CONFIG_SERIAL_8250=y
> CONFIG_SERIAL_8250_CONSOLE=y
> CONFIG_SERIAL_8250_PCI=y
> CONFIG_SERIAL_8250_NR_UARTS=4
> CONFIG_SERIAL_8250_RUNTIME_UARTS=4
> # CONFIG_SERIAL_8250_EXTENDED is not set
> 
> #
> # Non-8250 serial port support
> #
> CONFIG_SERIAL_CORE=y
> CONFIG_SERIAL_CORE_CONSOLE=y
> # CONFIG_SERIAL_JSM is not set
> CONFIG_UNIX98_PTYS=y
> CONFIG_LEGACY_PTYS=y
> CONFIG_LEGACY_PTY_COUNT=256
> 
> #
> # IPMI
> #
> # CONFIG_IPMI_HANDLER is not set
> 
> #
> # Watchdog Cards
> #
> # CONFIG_WATCHDOG is not set
> CONFIG_HW_RANDOM=y
> CONFIG_HW_RANDOM_INTEL=y
> CONFIG_HW_RANDOM_AMD=y
> CONFIG_HW_RANDOM_GEODE=y
> # CONFIG_NVRAM is not set
> CONFIG_RTC=y
> # CONFIG_RTC_HISTOGRAM is not set
> CONFIG_BLOCKER=y
> CONFIG_LPPTEST=y
> # CONFIG_DTLK is not set
> # CONFIG_R3964 is not set
> # CONFIG_APPLICOM is not set
> CONFIG_AGP=y
> CONFIG_AGP_AMD64=y
> # CONFIG_AGP_INTEL is not set
> # CONFIG_AGP_SIS is not set
> # CONFIG_AGP_VIA is not set
> # CONFIG_DRM is not set
> # CONFIG_MWAVE is not set
> # CONFIG_PC8736x_GPIO is not set
> CONFIG_RAW_DRIVER=y
> CONFIG_MAX_RAW_DEVS=256
> # CONFIG_HPET is not set
> CONFIG_HANGCHECK_TIMER=y
> 
> #
> # TPM devices
> #
> # CONFIG_TCG_TPM is not set
> # CONFIG_TELCLOCK is not set
> 
> #
> # I2C support
> #
> # CONFIG_I2C is not set
> 
> #
> # SPI support
> #
> # CONFIG_SPI is not set
> # CONFIG_SPI_MASTER is not set
> 
> #
> # Dallas's 1-wire bus
> #
> # CONFIG_W1 is not set
> 
> #
> # Hardware Monitoring support
> #
> CONFIG_HWMON=y
> # CONFIG_HWMON_VID is not set
> # CONFIG_SENSORS_ABITUGURU is not set
> # CONFIG_SENSORS_K8TEMP is not set
> # CONFIG_SENSORS_F71805F is not set
> # CONFIG_SENSORS_PC87427 is not set
> # CONFIG_SENSORS_VT1211 is not set
> # CONFIG_SENSORS_HDAPS is not set
> # CONFIG_HWMON_DEBUG_CHIP is not set
> 
> #
> # Multimedia devices
> #
> # CONFIG_VIDEO_DEV is not set
> 
> #
> # Digital Video Broadcasting Devices
> #
> # CONFIG_DVB is not set
> 
> #
> # Graphics support
> #
> CONFIG_FIRMWARE_EDID=y
> # CONFIG_FB is not set
> 
> #
> # Console display driver support
> #
> CONFIG_VGA_CONSOLE=y
> # CONFIG_VGACON_SOFT_SCROLLBACK is not set
> # CONFIG_VIDEO_SELECT is not set
> CONFIG_DUMMY_CONSOLE=y
> # CONFIG_BACKLIGHT_LCD_SUPPORT is not set
> CONFIG_BACKLIGHT_CLASS_DEVICE=y
> CONFIG_BACKLIGHT_DEVICE=y
> 
> #
> # Sound
> #
> CONFIG_SOUND=y
> 
> #
> # Advanced Linux Sound Architecture
> #
> # CONFIG_SND is not set
> 
> #
> # Open Sound System
> #
> CONFIG_SOUND_PRIME=y
> # CONFIG_SOUND_BT878 is not set
> # CONFIG_SOUND_ES1371 is not set
> CONFIG_SOUND_ICH=y
> # CONFIG_SOUND_TRIDENT is not set
> # CONFIG_SOUND_MSNDCLAS is not set
> # CONFIG_SOUND_MSNDPIN is not set
> # CONFIG_SOUND_VIA82CXXX is not set
> # CONFIG_SOUND_OSS is not set
> 
> #
> # HID Devices
> #
> CONFIG_HID=y
> 
> #
> # USB support
> #
> CONFIG_USB_ARCH_HAS_HCD=y
> CONFIG_USB_ARCH_HAS_OHCI=y
> CONFIG_USB_ARCH_HAS_EHCI=y
> # CONFIG_USB is not set
> 
> #
> # NOTE: USB_STORAGE enables SCSI, and 'SCSI disk support'
> #
> 
> #
> # USB Gadget Support
> #
> # CONFIG_USB_GADGET is not set
> 
> #
> # MMC/SD Card support
> #
> # CONFIG_MMC is not set
> 
> #
> # LED devices
> #
> # CONFIG_NEW_LEDS is not set
> 
> #
> # LED drivers
> #
> 
> #
> # LED Triggers
> #
> 
> #
> # InfiniBand support
> #
> # CONFIG_INFINIBAND is not set
> 
> #
> # EDAC - error detection and reporting (RAS) (EXPERIMENTAL)
> #
> # CONFIG_EDAC is not set
> 
> #
> # Real Time Clock
> #
> # CONFIG_RTC_CLASS is not set
> 
> #
> # DMA Engine support
> #
> # CONFIG_DMA_ENGINE is not set
> 
> #
> # DMA Clients
> #
> 
> #
> # DMA Devices
> #
> 
> #
> # Virtualization
> #
> # CONFIG_KVM is not set
> 
> #
> # Firmware Drivers
> #
> # CONFIG_EDD is not set
> # CONFIG_DELL_RBU is not set
> # CONFIG_DCDBAS is not set
> 
> #
> # File systems
> #
> CONFIG_EXT2_FS=y
> CONFIG_EXT2_FS_XATTR=y
> CONFIG_EXT2_FS_POSIX_ACL=y
> # CONFIG_EXT2_FS_SECURITY is not set
> # CONFIG_EXT2_FS_XIP is not set
> CONFIG_EXT3_FS=y
> CONFIG_EXT3_FS_XATTR=y
> CONFIG_EXT3_FS_POSIX_ACL=y
> # CONFIG_EXT3_FS_SECURITY is not set
> # CONFIG_EXT4DEV_FS is not set
> CONFIG_JBD=y
> # CONFIG_JBD_DEBUG is not set
> CONFIG_FS_MBCACHE=y
> CONFIG_REISERFS_FS=y
> # CONFIG_REISERFS_CHECK is not set
> # CONFIG_REISERFS_PROC_INFO is not set
> # CONFIG_REISERFS_FS_XATTR is not set
> CONFIG_JFS_FS=y
> # CONFIG_JFS_POSIX_ACL is not set
> # CONFIG_JFS_SECURITY is not set
> # CONFIG_JFS_DEBUG is not set
> # CONFIG_JFS_STATISTICS is not set
> CONFIG_FS_POSIX_ACL=y
> # CONFIG_XFS_FS is not set
> # CONFIG_GFS2_FS is not set
> # CONFIG_OCFS2_FS is not set
> # CONFIG_MINIX_FS is not set
> # CONFIG_ROMFS_FS is not set
> CONFIG_INOTIFY=y
> CONFIG_INOTIFY_USER=y
> # CONFIG_QUOTA is not set
> CONFIG_DNOTIFY=y
> CONFIG_AUTOFS_FS=y
> # CONFIG_AUTOFS4_FS is not set
> # CONFIG_FUSE_FS is not set
> 
> #
> # CD-ROM/DVD Filesystems
> #
> CONFIG_ISO9660_FS=y
> # CONFIG_JOLIET is not set
> # CONFIG_ZISOFS is not set
> # CONFIG_UDF_FS is not set
> 
> #
> # DOS/FAT/NT Filesystems
> #
> # CONFIG_MSDOS_FS is not set
> # CONFIG_VFAT_FS is not set
> # CONFIG_NTFS_FS is not set
> 
> #
> # Pseudo filesystems
> #
> CONFIG_PROC_FS=y
> CONFIG_PROC_KCORE=y
> CONFIG_PROC_SYSCTL=y
> CONFIG_SYSFS=y
> CONFIG_TMPFS=y
> # CONFIG_TMPFS_POSIX_ACL is not set
> # CONFIG_HUGETLBFS is not set
> # CONFIG_HUGETLB_PAGE is not set
> CONFIG_RAMFS=y
> # CONFIG_CONFIGFS_FS is not set
> 
> #
> # Miscellaneous filesystems
> #
> # CONFIG_ADFS_FS is not set
> # CONFIG_AFFS_FS is not set
> # CONFIG_HFS_FS is not set
> # CONFIG_HFSPLUS_FS is not set
> # CONFIG_BEFS_FS is not set
> # CONFIG_BFS_FS is not set
> # CONFIG_EFS_FS is not set
> # CONFIG_CRAMFS is not set
> # CONFIG_VXFS_FS is not set
> # CONFIG_HPFS_FS is not set
> # CONFIG_QNX4FS_FS is not set
> # CONFIG_SYSV_FS is not set
> # CONFIG_UFS_FS is not set
> 
> #
> # Network File Systems
> #
> CONFIG_NFS_FS=y
> CONFIG_NFS_V3=y
> # CONFIG_NFS_V3_ACL is not set
> # CONFIG_NFS_V4 is not set
> # CONFIG_NFS_DIRECTIO is not set
> CONFIG_NFSD=y
> CONFIG_NFSD_V3=y
> # CONFIG_NFSD_V3_ACL is not set
> # CONFIG_NFSD_V4 is not set
> CONFIG_NFSD_TCP=y
> CONFIG_LOCKD=y
> CONFIG_LOCKD_V4=y
> CONFIG_EXPORTFS=y
> CONFIG_NFS_COMMON=y
> CONFIG_SUNRPC=y
> # CONFIG_RPCSEC_GSS_KRB5 is not set
> # CONFIG_RPCSEC_GSS_SPKM3 is not set
> # CONFIG_SMB_FS is not set
> # CONFIG_CIFS is not set
> # CONFIG_NCP_FS is not set
> # CONFIG_CODA_FS is not set
> # CONFIG_AFS_FS is not set
> # CONFIG_9P_FS is not set
> 
> #
> # Partition Types
> #
> # CONFIG_PARTITION_ADVANCED is not set
> CONFIG_MSDOS_PARTITION=y
> 
> #
> # Native Language Support
> #
> CONFIG_NLS=y
> CONFIG_NLS_DEFAULT="iso8859-1"
> # CONFIG_NLS_CODEPAGE_437 is not set
> # CONFIG_NLS_CODEPAGE_737 is not set
> # CONFIG_NLS_CODEPAGE_775 is not set
> # CONFIG_NLS_CODEPAGE_850 is not set
> # CONFIG_NLS_CODEPAGE_852 is not set
> # CONFIG_NLS_CODEPAGE_855 is not set
> # CONFIG_NLS_CODEPAGE_857 is not set
> # CONFIG_NLS_CODEPAGE_860 is not set
> # CONFIG_NLS_CODEPAGE_861 is not set
> # CONFIG_NLS_CODEPAGE_862 is not set
> # CONFIG_NLS_CODEPAGE_863 is not set
> # CONFIG_NLS_CODEPAGE_864 is not set
> # CONFIG_NLS_CODEPAGE_865 is not set
> # CONFIG_NLS_CODEPAGE_866 is not set
> # CONFIG_NLS_CODEPAGE_869 is not set
> # CONFIG_NLS_CODEPAGE_936 is not set
> # CONFIG_NLS_CODEPAGE_950 is not set
> # CONFIG_NLS_CODEPAGE_932 is not set
> # CONFIG_NLS_CODEPAGE_949 is not set
> # CONFIG_NLS_CODEPAGE_874 is not set
> # CONFIG_NLS_ISO8859_8 is not set
> # CONFIG_NLS_CODEPAGE_1250 is not set
> # CONFIG_NLS_CODEPAGE_1251 is not set
> # CONFIG_NLS_ASCII is not set
> # CONFIG_NLS_ISO8859_1 is not set
> # CONFIG_NLS_ISO8859_2 is not set
> # CONFIG_NLS_ISO8859_3 is not set
> # CONFIG_NLS_ISO8859_4 is not set
> # CONFIG_NLS_ISO8859_5 is not set
> # CONFIG_NLS_ISO8859_6 is not set
> # CONFIG_NLS_ISO8859_7 is not set
> # CONFIG_NLS_ISO8859_9 is not set
> # CONFIG_NLS_ISO8859_13 is not set
> # CONFIG_NLS_ISO8859_14 is not set
> # CONFIG_NLS_ISO8859_15 is not set
> # CONFIG_NLS_KOI8_R is not set
> # CONFIG_NLS_KOI8_U is not set
> # CONFIG_NLS_UTF8 is not set
> 
> #
> # Distributed Lock Manager
> #
> # CONFIG_DLM is not set
> 
> #
> # Instrumentation Support
> #
> CONFIG_PROFILING=y
> CONFIG_OPROFILE=y
> # CONFIG_KPROBES is not set
> 
> #
> # Kernel hacking
> #
> CONFIG_TRACE_IRQFLAGS_SUPPORT=y
> # CONFIG_PRINTK_TIME is not set
> CONFIG_ENABLE_MUST_CHECK=y
> CONFIG_MAGIC_SYSRQ=y
> CONFIG_UNUSED_SYMBOLS=y
> # CONFIG_DEBUG_FS is not set
> # CONFIG_HEADERS_CHECK is not set
> CONFIG_DEBUG_KERNEL=y
> CONFIG_LOG_BUF_SHIFT=18
> CONFIG_DETECT_SOFTLOCKUP=y
> # CONFIG_SCHEDSTATS is not set
> # CONFIG_TIMER_STATS is not set
> # CONFIG_DEBUG_SLAB is not set
> CONFIG_DEBUG_PREEMPT=y
> # CONFIG_DEBUG_RT_MUTEXES is not set
> # CONFIG_RT_MUTEX_TESTER is not set
> # CONFIG_DEBUG_SPINLOCK is not set
> # CONFIG_DEBUG_RWSEMS is not set
> # CONFIG_DEBUG_LOCK_ALLOC is not set
> # CONFIG_PROVE_LOCKING is not set
> # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
> # CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
> CONFIG_PREEMPT_TRACE=y
> # CONFIG_EVENT_TRACE is not set
> # CONFIG_FUNCTION_TRACE is not set
> CONFIG_WAKEUP_TIMING=y
> # CONFIG_LATENCY_TRACE is not set
> # CONFIG_CRITICAL_PREEMPT_TIMING is not set
> # CONFIG_CRITICAL_IRQSOFF_TIMING is not set
> # CONFIG_WAKEUP_LATENCY_HIST is not set
> CONFIG_LATENCY_TIMING=y
> # CONFIG_DEBUG_KOBJECT is not set
> CONFIG_DEBUG_BUGVERBOSE=y
> # CONFIG_DEBUG_INFO is not set
> # CONFIG_DEBUG_VM is not set
> # CONFIG_DEBUG_LIST is not set
> # CONFIG_FRAME_POINTER is not set
> # CONFIG_UNWIND_INFO is not set
> CONFIG_FORCED_INLINING=y
> CONFIG_RCU_TORTURE_TEST=m
> # CONFIG_DEBUG_RODATA is not set
> CONFIG_IOMMU_DEBUG=y
> CONFIG_IOMMU_LEAK=y
> # CONFIG_DEBUG_STACKOVERFLOW is not set
> # CONFIG_DEBUG_STACK_USAGE is not set
> 
> #
> # Security options
> #
> # CONFIG_KEYS is not set
> # CONFIG_SECURITY is not set
> 
> #
> # Cryptographic options
> #
> # CONFIG_CRYPTO is not set
> 
> #
> # Library routines
> #
> CONFIG_BITREVERSE=y
> # CONFIG_CRC_CCITT is not set
> # CONFIG_CRC16 is not set
> CONFIG_CRC32=y
> # CONFIG_LIBCRC32C is not set
> CONFIG_PLIST=y
> CONFIG_IOMAP_COPY=y
> -
> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: BUG in 2.6.20-rt8

[Ingo Molnar]

* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz 
> Opteron box.  The machine continued to run a few rounds of kernbench 
> and LTP. Looks a bit scary -- a tasklet was "stolen" from 
> __tasklet_action().
> 
> Thoughts?  In the meantime, kicking it off again to see if it repeats.

> BUG: at kernel/softirq.c:559 __tasklet_action()

this seems to happen very sporadically. Seems to happen more likely on 
hyperthreading CPUs. It is very likely caused by the 
redesign-tasklet-locking-to-be-sane patch below - which is a quick hack 
of mine from early -rt days. Can you see any obvious bug in it? The 
cmpxchg logic is certainly a bit ... tricky, locking-wise.

	Ingo

---------------->
From: Ingo Molnar <mingo@elte.hu>

tasklet redesign: make it saner and make it easier to thread.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

----
 include/linux/interrupt.h |   39 ++++++-----
 kernel/softirq.c          |  155 +++++++++++++++++++++++++++++++---------------
 2 files changed, 128 insertions(+), 66 deletions(-)

Index: linux/include/linux/interrupt.h
===================================================================
--- linux.orig/include/linux/interrupt.h
+++ linux/include/linux/interrupt.h
@@ -276,8 +276,9 @@ extern void wait_for_softirq(int softirq
      to be executed on some cpu at least once after this.
    * If the tasklet is already scheduled, but its excecution is still not
      started, it will be executed only once.
-   * If this tasklet is already running on another CPU (or schedule is called
-     from tasklet itself), it is rescheduled for later.
+   * If this tasklet is already running on another CPU, it is rescheduled
+     for later.
+   * Schedule must not be called from the tasklet itself (a lockup occurs)
    * Tasklet is strictly serialized wrt itself, but not
      wrt another tasklets. If client needs some intertask synchronization,
      he makes it with spinlocks.
@@ -302,15 +303,25 @@ struct tasklet_struct name = { NULL, 0, 
 enum
 {
 	TASKLET_STATE_SCHED,	/* Tasklet is scheduled for execution */
-	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
+	TASKLET_STATE_RUN,	/* Tasklet is running (SMP only) */
+	TASKLET_STATE_PENDING	/* Tasklet is pending */
 };
 
-#ifdef CONFIG_SMP
+#define TASKLET_STATEF_SCHED	(1 << TASKLET_STATE_SCHED)
+#define TASKLET_STATEF_RUN	(1 << TASKLET_STATE_RUN)
+#define TASKLET_STATEF_PENDING	(1 << TASKLET_STATE_PENDING)
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
 static inline int tasklet_trylock(struct tasklet_struct *t)
 {
 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 }
 
+static inline int tasklet_tryunlock(struct tasklet_struct *t)
+{
+	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
+}
+
 static inline void tasklet_unlock(struct tasklet_struct *t)
 {
 	smp_mb__before_clear_bit(); 
@@ -322,9 +333,10 @@ static inline void tasklet_unlock_wait(s
 	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
 }
 #else
-#define tasklet_trylock(t) 1
-#define tasklet_unlock_wait(t) do { } while (0)
-#define tasklet_unlock(t) do { } while (0)
+# define tasklet_trylock(t)		1
+# define tasklet_tryunlock(t)		1
+# define tasklet_unlock_wait(t)		do { } while (0)
+# define tasklet_unlock(t)		do { } while (0)
 #endif
 
 extern void FASTCALL(__tasklet_schedule(struct tasklet_struct *t));
@@ -357,17 +369,8 @@ static inline void tasklet_disable(struc
 	smp_mb();
 }
 
-static inline void tasklet_enable(struct tasklet_struct *t)
-{
-	smp_mb__before_atomic_dec();
-	atomic_dec(&t->count);
-}
-
-static inline void tasklet_hi_enable(struct tasklet_struct *t)
-{
-	smp_mb__before_atomic_dec();
-	atomic_dec(&t->count);
-}
+extern fastcall void tasklet_enable(struct tasklet_struct *t);
+extern fastcall void tasklet_hi_enable(struct tasklet_struct *t);
 
 extern void tasklet_kill(struct tasklet_struct *t);
 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
Index: linux/kernel/softirq.c
===================================================================
--- linux.orig/kernel/softirq.c
+++ linux/kernel/softirq.c
@@ -464,14 +464,24 @@ struct tasklet_head
 static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL };
 static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL };
 
+static void inline
+__tasklet_common_schedule(struct tasklet_struct *t, struct tasklet_head *head, unsigned int nr)
+{
+	if (tasklet_trylock(t)) {
+		WARN_ON(t->next != NULL);
+		t->next = head->list;
+		head->list = t;
+		raise_softirq_irqoff(nr);
+		tasklet_unlock(t);
+	}
+}
+
 void fastcall __tasklet_schedule(struct tasklet_struct *t)
 {
 	unsigned long flags;
 
 	local_irq_save(flags);
-	t->next = __get_cpu_var(tasklet_vec).list;
-	__get_cpu_var(tasklet_vec).list = t;
-	raise_softirq_irqoff(TASKLET_SOFTIRQ);
+	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_vec), TASKLET_SOFTIRQ);
 	local_irq_restore(flags);
 }
 
@@ -482,81 +492,130 @@ void fastcall __tasklet_hi_schedule(stru
 	unsigned long flags;
 
 	local_irq_save(flags);
-	t->next = __get_cpu_var(tasklet_hi_vec).list;
-	__get_cpu_var(tasklet_hi_vec).list = t;
-	raise_softirq_irqoff(HI_SOFTIRQ);
+	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_hi_vec), HI_SOFTIRQ);
 	local_irq_restore(flags);
 }
 
 EXPORT_SYMBOL(__tasklet_hi_schedule);
 
-static void tasklet_action(struct softirq_action *a)
+void fastcall tasklet_enable(struct tasklet_struct *t)
 {
-	struct tasklet_struct *list;
+	if (!atomic_dec_and_test(&t->count))
+		return;
+	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
+		tasklet_schedule(t);
+}
 
-	local_irq_disable();
-	list = __get_cpu_var(tasklet_vec).list;
-	__get_cpu_var(tasklet_vec).list = NULL;
-	local_irq_enable();
+EXPORT_SYMBOL(tasklet_enable);
+
+void fastcall tasklet_hi_enable(struct tasklet_struct *t)
+{
+	if (!atomic_dec_and_test(&t->count))
+		return;
+	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
+		tasklet_hi_schedule(t);
+}
+
+EXPORT_SYMBOL(tasklet_hi_enable);
+
+static void
+__tasklet_action(struct softirq_action *a, struct tasklet_struct *list)
+{
+	int loops = 1000000;
 
 	while (list) {
 		struct tasklet_struct *t = list;
 
 		list = list->next;
+		/*
+		 * Should always succeed - after a tasklist got on the
+		 * list (after getting the SCHED bit set from 0 to 1),
+		 * nothing but the tasklet softirq it got queued to can
+		 * lock it:
+		 */
+		if (!tasklet_trylock(t)) {
+			WARN_ON(1);
+			continue;
+		}
+
+		t->next = NULL;
+
+		/*
+		 * If we cannot handle the tasklet because it's disabled,
+		 * mark it as pending. tasklet_enable() will later
+		 * re-schedule the tasklet.
+		 */
+		if (unlikely(atomic_read(&t->count))) {
+out_disabled:
+			/* implicit unlock: */
+			wmb();
+			t->state = TASKLET_STATEF_PENDING;
+			continue;
+		}
 
-		if (tasklet_trylock(t)) {
-			if (!atomic_read(&t->count)) {
-				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
-					BUG();
-				t->func(t->data);
+		/*
+		 * After this point on the tasklet might be rescheduled
+		 * on another CPU, but it can only be added to another
+		 * CPU's tasklet list if we unlock the tasklet (which we
+		 * dont do yet).
+		 */
+		if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+			WARN_ON(1);
+
+again:
+		t->func(t->data);
+
+		/*
+		 * Try to unlock the tasklet. We must use cmpxchg, because
+		 * another CPU might have scheduled or disabled the tasklet.
+		 * We only allow the STATE_RUN -> 0 transition here.
+		 */
+		while (!tasklet_tryunlock(t)) {
+			/*
+			 * If it got disabled meanwhile, bail out:
+			 */
+			if (atomic_read(&t->count))
+				goto out_disabled;
+			/*
+			 * If it got scheduled meanwhile, re-execute
+			 * the tasklet function:
+			 */
+			if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+				goto again;
+			if (!--loops) {
+				printk("hm, tasklet state: %08lx\n", t->state);
+				WARN_ON(1);
 				tasklet_unlock(t);
-				continue;
+				break;
 			}
-			tasklet_unlock(t);
 		}
-
-		local_irq_disable();
-		t->next = __get_cpu_var(tasklet_vec).list;
-		__get_cpu_var(tasklet_vec).list = t;
-		__do_raise_softirq_irqoff(TASKLET_SOFTIRQ);
-		local_irq_enable();
 	}
 }
 
-static void tasklet_hi_action(struct softirq_action *a)
+static void tasklet_action(struct softirq_action *a)
 {
 	struct tasklet_struct *list;
 
 	local_irq_disable();
-	list = __get_cpu_var(tasklet_hi_vec).list;
-	__get_cpu_var(tasklet_hi_vec).list = NULL;
+	list = __get_cpu_var(tasklet_vec).list;
+	__get_cpu_var(tasklet_vec).list = NULL;
 	local_irq_enable();
 
-	while (list) {
-		struct tasklet_struct *t = list;
+	__tasklet_action(a, list);
+}
 
-		list = list->next;
+static void tasklet_hi_action(struct softirq_action *a)
+{
+	struct tasklet_struct *list;
 
-		if (tasklet_trylock(t)) {
-			if (!atomic_read(&t->count)) {
-				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
-					BUG();
-				t->func(t->data);
-				tasklet_unlock(t);
-				continue;
-			}
-			tasklet_unlock(t);
-		}
+	local_irq_disable();
+	list = __get_cpu_var(tasklet_hi_vec).list;
+	__get_cpu_var(tasklet_hi_vec).list = NULL;
+	local_irq_enable();
 
-		local_irq_disable();
-		t->next = __get_cpu_var(tasklet_hi_vec).list;
-		__get_cpu_var(tasklet_hi_vec).list = t;
-		__do_raise_softirq_irqoff(HI_SOFTIRQ);
-		local_irq_enable();
-	}
+	__tasklet_action(a, list);
 }
 
-
 void tasklet_init(struct tasklet_struct *t,
 		  void (*func)(unsigned long), unsigned long data)
 {

Re: BUG in 2.6.20-rt8

[David Miller]

From: Ingo Molnar <mingo@elte.hu>
Date: Sun, 25 Feb 2007 07:27:47 +0100

> 
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> 
> > I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz 
> > Opteron box.  The machine continued to run a few rounds of kernbench 
> > and LTP. Looks a bit scary -- a tasklet was "stolen" from 
> > __tasklet_action().
> > 
> > Thoughts?  In the meantime, kicking it off again to see if it repeats.
> 
> > BUG: at kernel/softirq.c:559 __tasklet_action()
> 
> this seems to happen very sporadically. Seems to happen more likely on 
> hyperthreading CPUs. It is very likely caused by the 
> redesign-tasklet-locking-to-be-sane patch below - which is a quick hack 
> of mine from early -rt days. Can you see any obvious bug in it? The 
> cmpxchg logic is certainly a bit ... tricky, locking-wise.

Ingo, please don't use cmpxchg() in generic code, we support several
processors that simply cannot do it.

Instead of saying "it's just something special in -rt for now", take
it out now so that what you do eventually push upstream does get
tested.

Thanks.

Re: BUG in 2.6.20-rt8

[Paul E. McKenney]

On Sun, Feb 25, 2007 at 07:27:47AM +0100, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> 
> > I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz 
> > Opteron box.  The machine continued to run a few rounds of kernbench 
> > and LTP. Looks a bit scary -- a tasklet was "stolen" from 
> > __tasklet_action().
> > 
> > Thoughts?  In the meantime, kicking it off again to see if it repeats.
> 
> > BUG: at kernel/softirq.c:559 __tasklet_action()
> 
> this seems to happen very sporadically. Seems to happen more likely on 
> hyperthreading CPUs. It is very likely caused by the 
> redesign-tasklet-locking-to-be-sane patch below - which is a quick hack 
> of mine from early -rt days. Can you see any obvious bug in it? The 
> cmpxchg logic is certainly a bit ... tricky, locking-wise.

One thing thus far...

There is the repeated-reschedule case that looks like it can result
in a tasklet being dropped on the floor:

o	__tasklet_action() runs out of "loops" (at which point,
	we know TASKLET_STATE_SCHED is clear due to the prior test).

o	Someone calls tasklet_schedule(), which sets TASKLET_STATE_SCHED
	and calls __tasklet_schedule(), which fails in tasklet_trylock()
	due to __tasklet_action() still having the TASKLET_STATE_RUN
	bit set.  So the tasklet is not queued.

o	__tasklet_action() then forcibly unlocks, and the tasklet can
	never run again, because its TASKLET_STATE_SCHED is already
	set.

But this would have printed the "hm" message, which I didn't see.
And been a low-probability race on top of that.

And I have not yet come up with a better way of handling this -- and
if I did, it would likely involve more rather than less cmpxchg.  ;-)

If I can figure out a reasonable assertion, I will throw it at Promela
and see what happens.

						Thanx, Paul

> ---------------->
> From: Ingo Molnar <mingo@elte.hu>
> 
> tasklet redesign: make it saner and make it easier to thread.
> 
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> 
> ----
>  include/linux/interrupt.h |   39 ++++++-----
>  kernel/softirq.c          |  155 +++++++++++++++++++++++++++++++---------------
>  2 files changed, 128 insertions(+), 66 deletions(-)
> 
> Index: linux/include/linux/interrupt.h
> ===================================================================
> --- linux.orig/include/linux/interrupt.h
> +++ linux/include/linux/interrupt.h
> @@ -276,8 +276,9 @@ extern void wait_for_softirq(int softirq
>       to be executed on some cpu at least once after this.
>     * If the tasklet is already scheduled, but its excecution is still not
>       started, it will be executed only once.
> -   * If this tasklet is already running on another CPU (or schedule is called
> -     from tasklet itself), it is rescheduled for later.
> +   * If this tasklet is already running on another CPU, it is rescheduled
> +     for later.
> +   * Schedule must not be called from the tasklet itself (a lockup occurs)
>     * Tasklet is strictly serialized wrt itself, but not
>       wrt another tasklets. If client needs some intertask synchronization,
>       he makes it with spinlocks.
> @@ -302,15 +303,25 @@ struct tasklet_struct name = { NULL, 0, 
>  enum
>  {
>  	TASKLET_STATE_SCHED,	/* Tasklet is scheduled for execution */
> -	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
> +	TASKLET_STATE_RUN,	/* Tasklet is running (SMP only) */
> +	TASKLET_STATE_PENDING	/* Tasklet is pending */
>  };
> 
> -#ifdef CONFIG_SMP
> +#define TASKLET_STATEF_SCHED	(1 << TASKLET_STATE_SCHED)
> +#define TASKLET_STATEF_RUN	(1 << TASKLET_STATE_RUN)
> +#define TASKLET_STATEF_PENDING	(1 << TASKLET_STATE_PENDING)
> +
> +#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
>  static inline int tasklet_trylock(struct tasklet_struct *t)
>  {
>  	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
>  }
> 
> +static inline int tasklet_tryunlock(struct tasklet_struct *t)
> +{
> +	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
> +}
> +
>  static inline void tasklet_unlock(struct tasklet_struct *t)
>  {
>  	smp_mb__before_clear_bit(); 
> @@ -322,9 +333,10 @@ static inline void tasklet_unlock_wait(s
>  	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
>  }
>  #else
> -#define tasklet_trylock(t) 1
> -#define tasklet_unlock_wait(t) do { } while (0)
> -#define tasklet_unlock(t) do { } while (0)
> +# define tasklet_trylock(t)		1
> +# define tasklet_tryunlock(t)		1
> +# define tasklet_unlock_wait(t)		do { } while (0)
> +# define tasklet_unlock(t)		do { } while (0)
>  #endif
> 
>  extern void FASTCALL(__tasklet_schedule(struct tasklet_struct *t));
> @@ -357,17 +369,8 @@ static inline void tasklet_disable(struc
>  	smp_mb();
>  }
> 
> -static inline void tasklet_enable(struct tasklet_struct *t)
> -{
> -	smp_mb__before_atomic_dec();
> -	atomic_dec(&t->count);
> -}
> -
> -static inline void tasklet_hi_enable(struct tasklet_struct *t)
> -{
> -	smp_mb__before_atomic_dec();
> -	atomic_dec(&t->count);
> -}
> +extern fastcall void tasklet_enable(struct tasklet_struct *t);
> +extern fastcall void tasklet_hi_enable(struct tasklet_struct *t);
> 
>  extern void tasklet_kill(struct tasklet_struct *t);
>  extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
> Index: linux/kernel/softirq.c
> ===================================================================
> --- linux.orig/kernel/softirq.c
> +++ linux/kernel/softirq.c
> @@ -464,14 +464,24 @@ struct tasklet_head
>  static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL };
>  static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL };
> 
> +static void inline
> +__tasklet_common_schedule(struct tasklet_struct *t, struct tasklet_head *head, unsigned int nr)
> +{
> +	if (tasklet_trylock(t)) {
> +		WARN_ON(t->next != NULL);
> +		t->next = head->list;
> +		head->list = t;
> +		raise_softirq_irqoff(nr);
> +		tasklet_unlock(t);
> +	}
> +}
> +
>  void fastcall __tasklet_schedule(struct tasklet_struct *t)
>  {
>  	unsigned long flags;
> 
>  	local_irq_save(flags);
> -	t->next = __get_cpu_var(tasklet_vec).list;
> -	__get_cpu_var(tasklet_vec).list = t;
> -	raise_softirq_irqoff(TASKLET_SOFTIRQ);
> +	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_vec), TASKLET_SOFTIRQ);
>  	local_irq_restore(flags);
>  }
> 
> @@ -482,81 +492,130 @@ void fastcall __tasklet_hi_schedule(stru
>  	unsigned long flags;
> 
>  	local_irq_save(flags);
> -	t->next = __get_cpu_var(tasklet_hi_vec).list;
> -	__get_cpu_var(tasklet_hi_vec).list = t;
> -	raise_softirq_irqoff(HI_SOFTIRQ);
> +	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_hi_vec), HI_SOFTIRQ);
>  	local_irq_restore(flags);
>  }
> 
>  EXPORT_SYMBOL(__tasklet_hi_schedule);
> 
> -static void tasklet_action(struct softirq_action *a)
> +void fastcall tasklet_enable(struct tasklet_struct *t)
>  {
> -	struct tasklet_struct *list;
> +	if (!atomic_dec_and_test(&t->count))
> +		return;
> +	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
> +		tasklet_schedule(t);
> +}
> 
> -	local_irq_disable();
> -	list = __get_cpu_var(tasklet_vec).list;
> -	__get_cpu_var(tasklet_vec).list = NULL;
> -	local_irq_enable();
> +EXPORT_SYMBOL(tasklet_enable);
> +
> +void fastcall tasklet_hi_enable(struct tasklet_struct *t)
> +{
> +	if (!atomic_dec_and_test(&t->count))
> +		return;
> +	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
> +		tasklet_hi_schedule(t);
> +}
> +
> +EXPORT_SYMBOL(tasklet_hi_enable);
> +
> +static void
> +__tasklet_action(struct softirq_action *a, struct tasklet_struct *list)
> +{
> +	int loops = 1000000;
> 
>  	while (list) {
>  		struct tasklet_struct *t = list;
> 
>  		list = list->next;
> +		/*
> +		 * Should always succeed - after a tasklist got on the
> +		 * list (after getting the SCHED bit set from 0 to 1),
> +		 * nothing but the tasklet softirq it got queued to can
> +		 * lock it:
> +		 */
> +		if (!tasklet_trylock(t)) {
> +			WARN_ON(1);
> +			continue;
> +		}
> +
> +		t->next = NULL;
> +
> +		/*
> +		 * If we cannot handle the tasklet because it's disabled,
> +		 * mark it as pending. tasklet_enable() will later
> +		 * re-schedule the tasklet.
> +		 */
> +		if (unlikely(atomic_read(&t->count))) {
> +out_disabled:
> +			/* implicit unlock: */
> +			wmb();
> +			t->state = TASKLET_STATEF_PENDING;
> +			continue;
> +		}
> 
> -		if (tasklet_trylock(t)) {
> -			if (!atomic_read(&t->count)) {
> -				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
> -					BUG();
> -				t->func(t->data);
> +		/*
> +		 * After this point on the tasklet might be rescheduled
> +		 * on another CPU, but it can only be added to another
> +		 * CPU's tasklet list if we unlock the tasklet (which we
> +		 * dont do yet).
> +		 */
> +		if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
> +			WARN_ON(1);
> +
> +again:
> +		t->func(t->data);
> +
> +		/*
> +		 * Try to unlock the tasklet. We must use cmpxchg, because
> +		 * another CPU might have scheduled or disabled the tasklet.
> +		 * We only allow the STATE_RUN -> 0 transition here.
> +		 */
> +		while (!tasklet_tryunlock(t)) {
> +			/*
> +			 * If it got disabled meanwhile, bail out:
> +			 */
> +			if (atomic_read(&t->count))
> +				goto out_disabled;
> +			/*
> +			 * If it got scheduled meanwhile, re-execute
> +			 * the tasklet function:
> +			 */
> +			if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
> +				goto again;
> +			if (!--loops) {
> +				printk("hm, tasklet state: %08lx\n", t->state);
> +				WARN_ON(1);
>  				tasklet_unlock(t);
> -				continue;
> +				break;
>  			}
> -			tasklet_unlock(t);
>  		}
> -
> -		local_irq_disable();
> -		t->next = __get_cpu_var(tasklet_vec).list;
> -		__get_cpu_var(tasklet_vec).list = t;
> -		__do_raise_softirq_irqoff(TASKLET_SOFTIRQ);
> -		local_irq_enable();
>  	}
>  }
> 
> -static void tasklet_hi_action(struct softirq_action *a)
> +static void tasklet_action(struct softirq_action *a)
>  {
>  	struct tasklet_struct *list;
> 
>  	local_irq_disable();
> -	list = __get_cpu_var(tasklet_hi_vec).list;
> -	__get_cpu_var(tasklet_hi_vec).list = NULL;
> +	list = __get_cpu_var(tasklet_vec).list;
> +	__get_cpu_var(tasklet_vec).list = NULL;
>  	local_irq_enable();
> 
> -	while (list) {
> -		struct tasklet_struct *t = list;
> +	__tasklet_action(a, list);
> +}
> 
> -		list = list->next;
> +static void tasklet_hi_action(struct softirq_action *a)
> +{
> +	struct tasklet_struct *list;
> 
> -		if (tasklet_trylock(t)) {
> -			if (!atomic_read(&t->count)) {
> -				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
> -					BUG();
> -				t->func(t->data);
> -				tasklet_unlock(t);
> -				continue;
> -			}
> -			tasklet_unlock(t);
> -		}
> +	local_irq_disable();
> +	list = __get_cpu_var(tasklet_hi_vec).list;
> +	__get_cpu_var(tasklet_hi_vec).list = NULL;
> +	local_irq_enable();
> 
> -		local_irq_disable();
> -		t->next = __get_cpu_var(tasklet_hi_vec).list;
> -		__get_cpu_var(tasklet_hi_vec).list = t;
> -		__do_raise_softirq_irqoff(HI_SOFTIRQ);
> -		local_irq_enable();
> -	}
> +	__tasklet_action(a, list);
>  }
> 
> -
>  void tasklet_init(struct tasklet_struct *t,
>  		  void (*func)(unsigned long), unsigned long data)
>  {

Re: BUG in 2.6.20-rt8

[Paul E. McKenney]

On Sat, Feb 24, 2007 at 10:37:44PM -0800, David Miller wrote:
> From: Ingo Molnar <mingo@elte.hu>
> Date: Sun, 25 Feb 2007 07:27:47 +0100
> 
> > 
> > * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> > 
> > > I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz 
> > > Opteron box.  The machine continued to run a few rounds of kernbench 
> > > and LTP. Looks a bit scary -- a tasklet was "stolen" from 
> > > __tasklet_action().
> > > 
> > > Thoughts?  In the meantime, kicking it off again to see if it repeats.
> > 
> > > BUG: at kernel/softirq.c:559 __tasklet_action()
> > 
> > this seems to happen very sporadically. Seems to happen more likely on 
> > hyperthreading CPUs. It is very likely caused by the 
> > redesign-tasklet-locking-to-be-sane patch below - which is a quick hack 
> > of mine from early -rt days. Can you see any obvious bug in it? The 
> > cmpxchg logic is certainly a bit ... tricky, locking-wise.
> 
> Ingo, please don't use cmpxchg() in generic code, we support several
> processors that simply cannot do it.

OK, I will bite...

Why doesn't the traditional hash table of locks work here?  Use the
cache-line address as input to the hash function, take the corresponding
lock, do the compare-and-exchange by hand, and then release the lock.
What am I missing here?  Address aliasing do to memory being mapped into
multiple locations or something?  (In that case, use only the portion
of the address within the page, right?)

I will agree that cmpxchg() has been abused pretty thoroughly in
some venues, but it does have legitimate uses.

						Thanx, Paul

> Instead of saying "it's just something special in -rt for now", take
> it out now so that what you do eventually push upstream does get
> tested.

Re: BUG in 2.6.20-rt8

[David Miller]

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Sun, 25 Feb 2007 17:52:30 -0800

> Why doesn't the traditional hash table of locks work here?  Use the
> cache-line address as input to the hash function, take the corresponding
> lock, do the compare-and-exchange by hand, and then release the lock.
> What am I missing here?  Address aliasing do to memory being mapped into
> multiple locations or something?  (In that case, use only the portion
> of the address within the page, right?)

It doesn't protect against pure stores.

Even ignoring that you'll also need to disable interrupts, always,
which therefore will always perform very poorly compared to an
open-coded spinlock variant.

There are zero gains to cmpxchg(), in my opinion, you dirty and
grab exclusive access to a cacheline with cmpxchg() just the
same as a spinlock, so the real cost is the same.

There is zero justification for using this primitive in generic
code.

Re: BUG in 2.6.20-rt8

[Nick Piggin]

David Miller wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Date: Sun, 25 Feb 2007 17:52:30 -0800
> 
> 
>>Why doesn't the traditional hash table of locks work here?  Use the
>>cache-line address as input to the hash function, take the corresponding
>>lock, do the compare-and-exchange by hand, and then release the lock.
>>What am I missing here?  Address aliasing do to memory being mapped into
>>multiple locations or something?  (In that case, use only the portion
>>of the address within the page, right?)
> 
> 
> It doesn't protect against pure stores.

Use atomic_cmpxchg (or atomic_long_cmpxchg). The atomic_t type ensures
that unprotected stores don't happen (unless you try to do something
stupid, but you can break all other atomic_ ops like that anyway).

> Even ignoring that you'll also need to disable interrupts, always,
> which therefore will always perform very poorly compared to an
> open-coded spinlock variant.

But on those architectures, the same argument could also be said about
a lot of atomic_ operations in the generic kernel code (ie. just use
spinlocks).

> There are zero gains to cmpxchg(), in my opinion, you dirty and
> grab exclusive access to a cacheline with cmpxchg() just the
> same as a spinlock, so the real cost is the same.
> 
> There is zero justification for using this primitive in generic
> code.

IMO it is useful for when you are memory constrained (and bit locks
are no good because they require an atomic unlock). For example we
could actually cut down on a reasonable number of atomic ops by adding
a spinlock to struct page. However I suspect this wouldn't go down too
well.

With that said, our use of atomic operations in the kernel is probably
not an optimal balance for SMP sparc32 and parisc (ie. those platforms
might be a little faster with more spinlocks and less atomics). Does
it really matter, though?

-- 
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 

Re: BUG in 2.6.20-rt8

[Steven Rostedt]

On Sat, 2007-02-24 at 21:02 -0800, Paul E. McKenney wrote:
> Hello!
> 
> I got the following running stock 2.6.20-rt8 on an 4-CPU 1.8GHz Opteron
> box.  The machine continued to run a few rounds of kernbench and LTP.
> Looks a bit scary -- a tasklet was "stolen" from __tasklet_action().
> 
> Thoughts?  In the meantime, kicking it off again to see if it repeats.
> 
> 						Thanx, Paul
> 
> BUG: at kernel/softirq.c:559 __tasklet_action()
> 
> Call Trace:
>  [<ffffffff8022ec1b>] __tasklet_action+0xdb/0x120
>  [<ffffffff8022ee12>] ksoftirqd+0xf3/0x179
>  [<ffffffff8022ed1f>] ksoftirqd+0x0/0x179
>  [<ffffffff8023be23>] kthread+0xc8/0xf1
>  [<ffffffff8020a708>] child_rip+0xa/0x12
>  [<ffffffff8023bf27>] kthread_create+0x6e/0x159
>  [<ffffffff8023bd5b>] kthread+0x0/0xf1
>  [<ffffffff8020a6fe>] child_rip+0x0/0x12

Just updating linux-rt

John Stultz found the bug and provided a patch.

http://marc.info/?l=linux-kernel&m=118109631711031&w=2

-- Steve