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* 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568
@ 2006-12-18 17:48 Robert Crocombe
  2006-12-19 17:57 ` Ingo Molnar
  0 siblings, 1 reply; 6+ messages in thread
From: Robert Crocombe @ 2006-12-18 17:48 UTC (permalink / raw)
  To: linux-kernel, Ingo Molnar

[-- Attachment #1: Type: text/plain, Size: 2592 bytes --]

Almost exactly 24 hours after booting 2.6.19.1-rt15, I encountered the
following:

softirq-tasklet/49[CPU#3]: BUG in __tasklet_action at kernel/softirq.c:568

Call Trace:
 [<ffffffff8027aca3>] __WARN_ON+0x5c/0x74
 [<ffffffff8027c6e6>] __tasklet_action+0xae/0xf2
 [<ffffffff8027cccd>] ksoftirqd+0xfc/0x198
 [<ffffffff8027cbd1>] ksoftirqd+0x0/0x198
 [<ffffffff8022ed5b>] kthread+0xd1/0x101
 [<ffffffff80257bb8>] child_rip+0xa/0x12
 [<ffffffff8022ec8a>] kthread+0x0/0x101
 [<ffffffff80257bae>] child_rip+0x0/0x12

softirq-tasklet/36[CPU#2]: BUG in __tasklet_action at kernel/softirq.c:568

Call Trace:
 [<ffffffff8027aca3>] __WARN_ON+0x5c/0x74
 [<ffffffff8027c6e6>] __tasklet_action+0xae/0xf2
 [<ffffffff8027cccd>] ksoftirqd+0xfc/0x198
 [<ffffffff8027cbd1>] ksoftirqd+0x0/0x198
 [<ffffffff8022ed5b>] kthread+0xd1/0x101
 [<ffffffff80257bb8>] child_rip+0xa/0x12
 [<ffffffff8022ec8a>] kthread+0x0/0x101
 [<ffffffff80257bae>] child_rip+0x0/0x12

softirq-tasklet/49[CPU#3]: BUG in __tasklet_action at kernel/softirq.c:568

Call Trace:
 [<ffffffff8027aca3>] __WARN_ON+0x5c/0x74
 [<ffffffff8027c6e6>] __tasklet_action+0xae/0xf2
 [<ffffffff8027cccd>] ksoftirqd+0xfc/0x198
 [<ffffffff8027cbd1>] ksoftirqd+0x0/0x198
 [<ffffffff8022ed5b>] kthread+0xd1/0x101
 [<ffffffff80257bb8>] child_rip+0xa/0x12
 [<ffffffff8022ec8a>] kthread+0x0/0x101
 [<ffffffff80257bae>] child_rip+0x0/0x12

softirq-tasklet/49[CPU#3]: BUG in __tasklet_action at kernel/softirq.c:568

Call Trace:
 [<ffffffff8027aca3>] __WARN_ON+0x5c/0x74
 [<ffffffff8027c6e6>] __tasklet_action+0xae/0xf2
 [<ffffffff8027cccd>] ksoftirqd+0xfc/0x198
 [<ffffffff8027cbd1>] ksoftirqd+0x0/0x198
 [<ffffffff8022ed5b>] kthread+0xd1/0x101
 [<ffffffff80257bb8>] child_rip+0xa/0x12
 [<ffffffff8022ec8a>] kthread+0x0/0x101
 [<ffffffff80257bae>] child_rip+0x0/0x12

I had set the machine to do 1,000 kernel compiles the day before, but
it might have been finished by then (the BUG triggered on a Saturday).
 I did this because it was kernel compiles that previously triggered a
hard lockup on -rt kernels.  The machine seems to still be usable, and
the compiles all completed.

The referenced line is:
                /*
                 * 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);

This is a quad Opteron.  Config attached.

-- 
Robert Crocombe

[-- Attachment #2: config_2.6.19.1-rt15 --]
[-- Type: application/octet-stream, Size: 24400 bytes --]

#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.19.1-rt15
# Fri Dec 15 23:41:08 2006
#
CONFIG_X86_64=y
CONFIG_64BIT=y
CONFIG_X86=y
CONFIG_ZONE_DMA32=y
CONFIG_GENERIC_TIME=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_TIME_VSYSCALL=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_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="_00"
CONFIG_LOCALVERSION_AUTO=y
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
# CONFIG_IPC_NS is not set
CONFIG_POSIX_MQUEUE=y
# 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=y
CONFIG_IKCONFIG_PROC=y
CONFIG_CPUSETS=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=y
# 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=y
# CONFIG_MODULE_SRCVERSION_ALL is not set
CONFIG_KMOD=y
CONFIG_STOP_MACHINE=y

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

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

#
# Processor type and features
#
CONFIG_X86_PC=y
# CONFIG_X86_VSMP is not set
CONFIG_MK8=y
# CONFIG_MPSC 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 is not set
CONFIG_HIGH_RES_TIMERS=y
# CONFIG_NO_HZ 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=y
CONFIG_NUMA=y
CONFIG_RWSEM_GENERIC_SPINLOCK=y
# CONFIG_K8_NUMA is not set
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 is not set
CONFIG_X86_MCE_AMD=y
# CONFIG_KEXEC is not set
# CONFIG_CRASH_DUMP is not set
CONFIG_PHYSICAL_START=0x200000
# CONFIG_SECCOMP is not set
# CONFIG_CC_STACKPROTECTOR is not set
# CONFIG_HZ_100 is not set
CONFIG_HZ_250=y
# CONFIG_HZ_1000 is not set
CONFIG_HZ=250
CONFIG_REORDER=y
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 is not set
# CONFIG_ACPI_BATTERY is not set
# CONFIG_ACPI_BUTTON is not set
# CONFIG_ACPI_VIDEO is not set
# CONFIG_ACPI_HOTKEY is not set
# CONFIG_ACPI_FAN is not set
# CONFIG_ACPI_DOCK is not set
# CONFIG_ACPI_PROCESSOR is not set
CONFIG_ACPI_NUMA=y
# CONFIG_ACPI_ASUS is not set
# CONFIG_ACPI_IBM is not set
# CONFIG_ACPI_TOSHIBA is not set
CONFIG_ACPI_BLACKLIST_YEAR=0
# CONFIG_ACPI_DEBUG is not set
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=y
CONFIG_PCIEAER=y
CONFIG_PCI_MSI=y
# 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=y
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_NET_KEY is not set
CONFIG_INET=y
# CONFIG_IP_MULTICAST is not set
# 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_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 is not set
# CONFIG_INET_XFRM_MODE_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_DIAG is not set
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# 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=y
# 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_UB 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 is not set

#
# SCSI device support
#
CONFIG_RAID_ATTRS=y
CONFIG_SCSI=y
# 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 is not set
CONFIG_SCSI_CONSTANTS=y
# CONFIG_SCSI_LOGGING 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=y
CONFIG_AIC79XX_CMDS_PER_DEVICE=32
CONFIG_AIC79XX_RESET_DELAY_MS=4000
# CONFIG_AIC79XX_ENABLE_RD_STRM is not set
# CONFIG_AIC79XX_DEBUG_ENABLE is not set
CONFIG_AIC79XX_DEBUG_MASK=0
# CONFIG_AIC79XX_REG_PRETTY_PRINT 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 is not set
# 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

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

#
# Multi-device support (RAID and LVM)
#
CONFIG_MD=y
CONFIG_BLK_DEV_MD=y
# CONFIG_MD_LINEAR is not set
# CONFIG_MD_RAID0 is not set
CONFIG_MD_RAID1=y
# CONFIG_MD_RAID10 is not set
# CONFIG_MD_RAID456 is not set
# CONFIG_MD_MULTIPATH is not set
# CONFIG_MD_FAULTY is not set
CONFIG_BLK_DEV_DM=y
# CONFIG_DM_DEBUG is not set
# CONFIG_DM_CRYPT is not set
# CONFIG_DM_SNAPSHOT is not set
# CONFIG_DM_MIRROR is not set
# CONFIG_DM_ZERO is not set
# CONFIG_DM_MULTIPATH is not set

#
# Fusion MPT device support
#
# CONFIG_FUSION is not set
# CONFIG_FUSION_SPI is not set
# CONFIG_FUSION_FC is not set
# CONFIG_FUSION_SAS is not set

#
# IEEE 1394 (FireWire) support
#
CONFIG_IEEE1394=m

#
# Subsystem Options
#
# CONFIG_IEEE1394_VERBOSEDEBUG is not set
# CONFIG_IEEE1394_OUI_DB is not set
# CONFIG_IEEE1394_EXTRA_CONFIG_ROMS is not set
# CONFIG_IEEE1394_EXPORT_FULL_API is not set

#
# Device Drivers
#

#
# Texas Instruments PCILynx requires I2C
#
CONFIG_IEEE1394_OHCI1394=m

#
# Protocol Drivers
#
# CONFIG_IEEE1394_VIDEO1394 is not set
# CONFIG_IEEE1394_SBP2 is not set
# CONFIG_IEEE1394_ETH1394 is not set
# CONFIG_IEEE1394_DV1394 is not set
CONFIG_IEEE1394_RAWIO=m

#
# 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
#

#
# Ethernet (10 or 100Mbit)
#
# CONFIG_NET_ETHERNET is not set

#
# Ethernet (1000 Mbit)
#
# CONFIG_ACENIC is not set
# CONFIG_DL2K is not set
CONFIG_E1000=m
CONFIG_E1000_NAPI=y
# 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_TIGON3=m
# 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

#
# 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 is not set
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1920
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=1200
# 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 is not set

#
# IPMI
#
# CONFIG_IPMI_HANDLER is not set

#
# Watchdog Cards
#
CONFIG_WATCHDOG=y
# CONFIG_WATCHDOG_NOWAYOUT is not set

#
# Watchdog Device Drivers
#
CONFIG_SOFT_WATCHDOG=y
# CONFIG_ACQUIRE_WDT is not set
# CONFIG_ADVANTECH_WDT is not set
# CONFIG_ALIM1535_WDT is not set
# CONFIG_ALIM7101_WDT is not set
# CONFIG_SC520_WDT is not set
# CONFIG_EUROTECH_WDT is not set
# CONFIG_IB700_WDT is not set
# CONFIG_IBMASR is not set
# CONFIG_WAFER_WDT is not set
# CONFIG_I6300ESB_WDT is not set
# CONFIG_I8XX_TCO is not set
# CONFIG_ITCO_WDT is not set
# CONFIG_SC1200_WDT is not set
# CONFIG_60XX_WDT is not set
# CONFIG_SBC8360_WDT is not set
# CONFIG_CPU5_WDT is not set
# CONFIG_SMSC37B787_WDT is not set
# CONFIG_W83627HF_WDT is not set
# CONFIG_W83697HF_WDT is not set
# CONFIG_W83877F_WDT is not set
# CONFIG_W83977F_WDT is not set
# CONFIG_MACHZ_WDT is not set
# CONFIG_SBC_EPX_C3_WATCHDOG is not set

#
# PCI-based Watchdog Cards
#
# CONFIG_PCIPCWATCHDOG is not set
# CONFIG_WDTPCI is not set

#
# USB-based Watchdog Cards
#
# CONFIG_USBPCWATCHDOG is not set
# CONFIG_HW_RANDOM is not set
# CONFIG_NVRAM is not set
CONFIG_RTC=y
# CONFIG_RTC_HISTOGRAM is not set
# CONFIG_BLOCKER is not set
# CONFIG_LPPTEST is not set
# CONFIG_DTLK is not set
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set

#
# Ftape, the floppy tape device driver
#
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=m
# CONFIG_DRM_TDFX is not set
# CONFIG_DRM_R128 is not set
# CONFIG_DRM_RADEON is not set
# CONFIG_DRM_MGA is not set
# CONFIG_DRM_SIS is not set
# CONFIG_DRM_VIA is not set
# CONFIG_DRM_SAVAGE is not set
# CONFIG_MWAVE is not set
# CONFIG_PC8736x_GPIO is not set
# CONFIG_RAW_DRIVER is not set
CONFIG_HPET=y
# CONFIG_HPET_RTC_IRQ is not set
# CONFIG_HPET_MMAP is not set
# CONFIG_HANGCHECK_TIMER is not set

#
# 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 is not set
# CONFIG_HWMON_VID is not set

#
# Multimedia devices
#
# CONFIG_VIDEO_DEV is not set

#
# Digital Video Broadcasting Devices
#
# CONFIG_DVB is not set
# CONFIG_USB_DABUSB 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=y
CONFIG_BACKLIGHT_CLASS_DEVICE=m
CONFIG_BACKLIGHT_DEVICE=y
CONFIG_LCD_CLASS_DEVICE=m
CONFIG_LCD_DEVICE=y

#
# Sound
#
# CONFIG_SOUND is not set

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

#
# Miscellaneous USB options
#
# CONFIG_USB_DEVICEFS is not set
# CONFIG_USB_BANDWIDTH is not set
# CONFIG_USB_DYNAMIC_MINORS is not set
# CONFIG_USB_SUSPEND is not set
# CONFIG_USB_OTG is not set

#
# USB Host Controller Drivers
#
CONFIG_USB_EHCI_HCD=y
# CONFIG_USB_EHCI_SPLIT_ISO is not set
# CONFIG_USB_EHCI_ROOT_HUB_TT is not set
# CONFIG_USB_EHCI_TT_NEWSCHED is not set
# CONFIG_USB_ISP116X_HCD is not set
CONFIG_USB_OHCI_HCD=y
# CONFIG_USB_OHCI_BIG_ENDIAN is not set
CONFIG_USB_OHCI_LITTLE_ENDIAN=y
CONFIG_USB_UHCI_HCD=y
# CONFIG_USB_SL811_HCD is not set

#
# USB Device Class drivers
#
# CONFIG_USB_ACM is not set
# CONFIG_USB_PRINTER is not set

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

#
# may also be needed; see USB_STORAGE Help for more information
#
# CONFIG_USB_STORAGE is not set
# CONFIG_USB_LIBUSUAL is not set

#
# USB Input Devices
#
CONFIG_USB_HID=y
CONFIG_USB_HIDINPUT=y
# CONFIG_USB_HIDINPUT_POWERBOOK is not set
# CONFIG_HID_FF is not set
# CONFIG_USB_HIDDEV is not set
# CONFIG_USB_AIPTEK is not set
# CONFIG_USB_WACOM is not set
# CONFIG_USB_ACECAD is not set
# CONFIG_USB_KBTAB is not set
# CONFIG_USB_POWERMATE is not set
# CONFIG_USB_TOUCHSCREEN is not set
# CONFIG_USB_YEALINK is not set
# CONFIG_USB_XPAD is not set
# CONFIG_USB_ATI_REMOTE is not set
# CONFIG_USB_ATI_REMOTE2 is not set
# CONFIG_USB_KEYSPAN_REMOTE is not set
# CONFIG_USB_APPLETOUCH is not set

#
# USB Imaging devices
#
# CONFIG_USB_MDC800 is not set
# CONFIG_USB_MICROTEK is not set

#
# USB Network Adapters
#
# CONFIG_USB_CATC is not set
# CONFIG_USB_KAWETH is not set
# CONFIG_USB_PEGASUS is not set
# CONFIG_USB_RTL8150 is not set
# CONFIG_USB_USBNET_MII is not set
# CONFIG_USB_USBNET is not set
# CONFIG_USB_MON is not set

#
# USB port drivers
#

#
# USB Serial Converter support
#
# CONFIG_USB_SERIAL is not set

#
# USB Miscellaneous drivers
#
# CONFIG_USB_EMI62 is not set
# CONFIG_USB_EMI26 is not set
# CONFIG_USB_ADUTUX is not set
# CONFIG_USB_AUERSWALD is not set
# CONFIG_USB_RIO500 is not set
# CONFIG_USB_LEGOTOWER is not set
# CONFIG_USB_LCD is not set
# CONFIG_USB_LED is not set
# CONFIG_USB_CYPRESS_CY7C63 is not set
# CONFIG_USB_CYTHERM is not set
# CONFIG_USB_PHIDGET is not set
# CONFIG_USB_IDMOUSE is not set
# CONFIG_USB_FTDI_ELAN is not set
# CONFIG_USB_APPLEDISPLAY is not set
# CONFIG_USB_SISUSBVGA is not set
# CONFIG_USB_LD is not set
# CONFIG_USB_TRANCEVIBRATOR is not set

#
# USB DSL modem 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
#
# 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 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 is not set
# CONFIG_JFS_FS 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 is not set
CONFIG_AUTOFS4_FS=y
# CONFIG_FUSE_FS is not set

#
# CD-ROM/DVD Filesystems
#
# CONFIG_ISO9660_FS 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=y
CONFIG_HUGETLB_PAGE=y
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 is not set
# CONFIG_NFSD 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 is not set

#
# Instrumentation Support
#
# CONFIG_PROFILING is not set
# 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 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 is not set
# 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_EVENT_TRACE is not set
# CONFIG_WAKEUP_TIMING is not set
# CONFIG_CRITICAL_PREEMPT_TIMING is not set
# CONFIG_CRITICAL_IRQSOFF_TIMING is not set
# CONFIG_DEBUG_KOBJECT is not set
# CONFIG_DEBUG_INFO is not set
# CONFIG_DEBUG_FS 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_HEADERS_CHECK is not set
# CONFIG_RCU_TORTURE_TEST is not set
CONFIG_DEBUG_RODATA=y
CONFIG_IOMMU_DEBUG=y
# CONFIG_IOMMU_LEAK is not set
# 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_CRC_CCITT is not set
# CONFIG_CRC16 is not set
CONFIG_CRC32=y
# CONFIG_LIBCRC32C is not set
CONFIG_PLIST=y

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568
  2006-12-18 17:48 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568 Robert Crocombe
@ 2006-12-19 17:57 ` Ingo Molnar
  2006-12-20 12:37   ` Robert Crocombe
  0 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2006-12-19 17:57 UTC (permalink / raw)
  To: Robert Crocombe; +Cc: linux-kernel


* Robert Crocombe <rcrocomb@gmail.com> wrote:

> Almost exactly 24 hours after booting 2.6.19.1-rt15, I encountered the
> following:
> 
> softirq-tasklet/49[CPU#3]: BUG in __tasklet_action at kernel/softirq.c:568

yeah. This is something that triggers very rarely on certain boxes. Not 
fixed yet, and it's been around for some time.

	Ingo

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568
  2006-12-19 17:57 ` Ingo Molnar
@ 2006-12-20 12:37   ` Robert Crocombe
  2006-12-20 19:50     ` Ingo Molnar
  0 siblings, 1 reply; 6+ messages in thread
From: Robert Crocombe @ 2006-12-20 12:37 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: linux-kernel

On 12/19/06, Ingo Molnar <mingo@elte.hu> wrote:
> yeah. This is something that triggers very rarely on certain boxes. Not
> fixed yet, and it's been around for some time.

Is there anything you would like me to do to help diagnose this?

-- 
Robert Crocombe
rcrocomb@gmail.com

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568
  2006-12-20 12:37   ` Robert Crocombe
@ 2006-12-20 19:50     ` Ingo Molnar
  2006-12-21  3:19       ` Steven Rostedt
  0 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2006-12-20 19:50 UTC (permalink / raw)
  To: Robert Crocombe; +Cc: linux-kernel


* Robert Crocombe <rcrocomb@gmail.com> wrote:

> On 12/19/06, Ingo Molnar <mingo@elte.hu> wrote:
> >yeah. This is something that triggers very rarely on certain boxes. Not
> >fixed yet, and it's been around for some time.
> 
> Is there anything you would like me to do to help diagnose this?

to figure out what the bug is :-/ Below is the tasklet redesign patch - 
the bug must be in there somewhere.

	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
@@ -288,8 +288,9 @@ 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.
@@ -314,15 +315,25 @@ 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(); 
@@ -334,9 +345,10 @@ 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));
@@ -369,17 +381,8 @@ 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
@@ -463,14 +463,24 @@ 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);
 }
 
@@ -481,81 +491,130 @@ 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)
 {

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568
  2006-12-20 19:50     ` Ingo Molnar
@ 2006-12-21  3:19       ` Steven Rostedt
  2006-12-26 23:40         ` Ingo Molnar
  0 siblings, 1 reply; 6+ messages in thread
From: Steven Rostedt @ 2006-12-21  3:19 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: Robert Crocombe, linux-kernel

On Wed, 2006-12-20 at 20:50 +0100, Ingo Molnar wrote:
> * Robert Crocombe <rcrocomb@gmail.com> wrote:
> 
> > On 12/19/06, Ingo Molnar <mingo@elte.hu> wrote:
> > >yeah. This is something that triggers very rarely on certain boxes. Not
> > >fixed yet, and it's been around for some time.
> > 
> > Is there anything you would like me to do to help diagnose this?
> 
> to figure out what the bug is :-/ Below is the tasklet redesign patch - 
> the bug must be in there somewhere.

> +static inline int tasklet_tryunlock(struct tasklet_struct *t)
> +{
> +	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
> +}
> +

This probably isn't it, but is cmpxchg available on all archs now?

-- Steve



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568
  2006-12-21  3:19       ` Steven Rostedt
@ 2006-12-26 23:40         ` Ingo Molnar
  0 siblings, 0 replies; 6+ messages in thread
From: Ingo Molnar @ 2006-12-26 23:40 UTC (permalink / raw)
  To: Steven Rostedt; +Cc: Robert Crocombe, linux-kernel


* Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 2006-12-20 at 20:50 +0100, Ingo Molnar wrote:
> > * Robert Crocombe <rcrocomb@gmail.com> wrote:
> > 
> > > On 12/19/06, Ingo Molnar <mingo@elte.hu> wrote:
> > > >yeah. This is something that triggers very rarely on certain boxes. Not
> > > >fixed yet, and it's been around for some time.
> > > 
> > > Is there anything you would like me to do to help diagnose this?
> > 
> > to figure out what the bug is :-/ Below is the tasklet redesign patch - 
> > the bug must be in there somewhere.
> 
> > +static inline int tasklet_tryunlock(struct tasklet_struct *t)
> > +{
> > +	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
> > +}
> > +
> 
> This probably isn't it, but is cmpxchg available on all archs now?

yeah, it's probably not related, i saw these failures on plain i686 too, 
which definitely has cmpxchg support. The failures i saw happened on a 
hyperthreading CPU, so i guess it must be some sort of narrow race.

	Ingo

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2006-12-26 23:43 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2006-12-18 17:48 2.6.19.1-rt15: BUG in __tasklet_action at kernel/softirq.c:568 Robert Crocombe
2006-12-19 17:57 ` Ingo Molnar
2006-12-20 12:37   ` Robert Crocombe
2006-12-20 19:50     ` Ingo Molnar
2006-12-21  3:19       ` Steven Rostedt
2006-12-26 23:40         ` Ingo Molnar

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