Commit graph android_kernel_sony_sdm845/kernel/hung_task.c
Message SHA1
Merge android-4.9.170 (1ef64da) into msm-4.9
* refs/heads/tmp-1ef64da:
  Linux 4.9.170
  appletalk: Fix compile regression
  net: stmmac: Set dma ring length before enabling the DMA
  tpm/tpm_crb: Avoid unaligned reads in crb_recv()
  include/linux/swap.h: use offsetof() instead of custom __swapoffset macro
  lib/div64.c: off by one in shift
  appletalk: Fix use-after-free in atalk_proc_exit
  ARM: 8839/1: kprobe: make patch_lock a raw_spinlock_t
  lkdtm: Add tests for NULL pointer dereference
  soc/tegra: pmc: Drop locking from tegra_powergate_is_powered()
  iommu/dmar: Fix buffer overflow during PCI bus notification
  crypto: sha512/arm - fix crash bug in Thumb2 build
  crypto: sha256/arm - fix crash bug in Thumb2 build
  kernel: hung_task.c: disable on suspend
  cifs: fallback to older infolevels on findfirst queryinfo retry
  ACPI / SBS: Fix GPE storm on recent MacBookPro's
  ARM: samsung: Limit SAMSUNG_PM_CHECK config option to non-Exynos platforms
  HID: i2c-hid: override HID descriptors for certain devices
  serial: uartps: console_setup() can't be placed to init section
  f2fs: fix to do sanity check with current segment number
  9p locks: add mount option for lock retry interval
  9p: do not trust pdu content for stat item size
  rsi: improve kernel thread handling to fix kernel panic
  gpio: pxa: handle corner case of unprobed device
  ext4: prohibit fstrim in norecovery mode
  fix incorrect error code mapping for OBJECTID_NOT_FOUND
  x86/hw_breakpoints: Make default case in hw_breakpoint_arch_parse() return an error
  iommu/vt-d: Check capability before disabling protected memory
  x86/cpu/cyrix: Use correct macros for Cyrix calls on Geode processors
  x86/hpet: Prevent potential NULL pointer dereference
  irqchip/mbigen: Don't clear eventid when freeing an MSI
  perf tests: Fix a memory leak in test__perf_evsel__tp_sched_test()
  perf tests: Fix a memory leak of cpu_map object in the openat_syscall_event_on_all_cpus test
  perf evsel: Free evsel->counts in perf_evsel__exit()
  perf hist: Add missing map__put() in error case
  perf top: Fix error handling in cmd_top()
  perf build-id: Fix memory leak in print_sdt_events()
  perf config: Fix a memory leak in collect_config()
  perf config: Fix an error in the config template documentation
  tools/power turbostat: return the exit status of a command
  thermal/int340x_thermal: fix mode setting
  thermal/int340x_thermal: Add additional UUIDs
  ALSA: opl3: fix mismatch between snd_opl3_drum_switch definition and declaration
  mmc: davinci: remove extraneous __init annotation
  IB/mlx4: Fix race condition between catas error reset and aliasguid flows
  ALSA: sb8: add a check for request_region
  ALSA: echoaudio: add a check for ioremap_nocache
  ext4: report real fs size after failed resize
  ext4: add missing brelse() in add_new_gdb_meta_bg()
  perf/core: Restore mmap record type correctly
  ARC: u-boot args: check that magic number is correct
  ANDROID: cuttlefish_defconfig: Enable L2TP/PPTP
  ANDROID: Makefile: Properly resolve 4.9.169 merge
  Make arm64 serial port config compatible with crosvm

Change-Id: If6d1962cc2aaf4dccc1e3b4495e9bb77ae6dadac
Signed-off-by: jianzhou <jianzhou@codeaurora.org>

jianzhou   commited 2019-05-30 14:15:13 +08:00
7b323f5e90
kernel: hung_task.c: disable on suspend
[ Upstream commit a1c6ca3c6de763459a6e93b644ec6518c890ba1c ]

It is possible to observe hung_task complaints when system goes to
suspend-to-idle state:

 # echo freeze > /sys/power/state

 PM: Syncing filesystems ... done.
 Freezing user space processes ... (elapsed 0.001 seconds) done.
 OOM killer disabled.
 Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
 sd 0:0:0:0: [sda] Synchronizing SCSI cache
 INFO: task bash:1569 blocked for more than 120 seconds.
       Not tainted 4.19.0-rc3_+ #687
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 bash            D    0  1569    604 0x00000000
 Call Trace:
  ? __schedule+0x1fe/0x7e0
  schedule+0x28/0x80
  suspend_devices_and_enter+0x4ac/0x750
  pm_suspend+0x2c0/0x310

Register a PM notifier to disable the detector on suspend and re-enable
back on wakeup.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Vitaly Kuznetsov   authored and   Greg Kroah-Hartman   commited 2019-04-20 09:07:52 +02:00
e538759bd9
Merge android-4.9.160 (fd5657a) into msm-4.9
* refs/heads/tmp-fd5657a:
  Linux 4.9.160
  ax25: fix possible use-after-free
  mISDN: fix a race in dev_expire_timer()
  net/x25: do not hold the cpu too long in x25_new_lci()
  btrfs: Remove false alert when fiemap range is smaller than on-disk extent
  net: ipv4: use a dedicated counter for icmp_v4 redirect packets
  net: stmmac: Fix a race in EEE enable callback
  vxlan: test dev->flags & IFF_UP before calling netif_rx()
  tcp: clear icsk_backoff in tcp_write_queue_purge()
  net: Do not allocate page fragments that are not skb aligned
  tcp: tcp_v4_err() should be more careful
  net: Add header for usage of fls64()
  vhost: correctly check the return value of translate_desc() in log_used()
  sky2: Increase D3 delay again
  net: stmmac: handle endianness in dwmac4_get_timestamp
  net: phy: xgmiitorgmii: Support generic PHY status read
  net: Fix for_each_netdev_feature on Big endian
  hwmon: (lm80) Fix missing unlock on error in set_fan_div()
  vsock: cope with memory allocation failure at socket creation time
  net: fix IPv6 prefix route residue
  Build break
  FROMLIST: BACKPORT: overlayfs: override_creds=off option bypass creator_cred
  Linux 4.9.159
  Revert "scsi: aic94xx: fix module loading"
  uapi/if_ether.h: move __UAPI_DEF_ETHHDR libc define
  mm: stop leaking PageTables
  pinctrl: msm: fix gpio-hog related boot issues
  netfilter: nf_tables: fix mismatch in big-endian system
  usb: dwc2: Remove unnecessary kfree
  kaweth: use skb_cow_head() to deal with cloned skbs
  ch9200: use skb_cow_head() to deal with cloned skbs
  smsc95xx: Use skb_cow_head to deal with cloned skbs
  drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set
  dm thin: fix bug where bio that overwrites thin block ignores FUA
  x86/a.out: Clear the dump structure initially
  signal: Restore the stop PTRACE_EVENT_EXIT
  x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls
  tracing/uprobes: Fix output for multiple string arguments
  alpha: Fix Eiger NR_IRQS to 128
  alpha: fix page fault handling for r16-r18 targets
  Input: elantech - enable 3rd button support on Fujitsu CELSIUS H780
  Input: bma150 - register input device after setting private data
  kvm: vmx: Fix entry number check for add_atomic_switch_msr()
  ALSA: usb-audio: Fix implicit fb endpoint setup by quirk
  ALSA: hda - Add quirk for HP EliteBook 840 G5
  perf/x86: Add check_period PMU callback
  perf/core: Fix impossible ring-buffer sizes warning
  Input: elan_i2c - add ACPI ID for touchpad in Lenovo V330-15ISK
  Revert "Input: elan_i2c - add ACPI ID for touchpad in ASUS Aspire F5-573G"
  perf report: Include partial stacks unwound with libdw
  cifs: Limit memory used by lock request calls to a page
  gpio: pl061: handle failed allocations
  ARM: dts: kirkwood: Fix polarity of GPIO fan lines
  ARM: dts: da850-lcdk: Correct the sound card name
  ARM: dts: da850-evm: Correct the sound card name
  drm/bridge: tc358767: fix output H/V syncs
  drm/bridge: tc358767: reject modes which require too much BW
  drm/bridge: tc358767: fix initial DP0/1_SRCCTRL value
  drm/bridge: tc358767: fix single lane configuration
  drm/bridge: tc358767: add defines for DP1_SRCCTRL & PHY_2LANE
  cpufreq: check if policy is inactive early in __cpufreq_get()
  ACPI: NUMA: Use correct type for printing addresses on i386-PAE
  bnx2x: disable GSO where gso_size is too big for hardware
  net: create skb_gso_validate_mac_len()
  ARM: fix the cockup in the previous patch
  ARM: ensure that processor vtables is not lost after boot
  ARM: spectre-v2: per-CPU vtables to work around big.Little systems
  ARM: add PROC_VTABLE and PROC_TABLE macros
  ARM: clean up per-processor check_bugs method call
  ARM: split out processor lookup
  ARM: make lookup_processor_type() non-__init
  ARM: 8810/1: vfp: Fix wrong assignement to ufp_exc
  ARM: 8797/1: spectre-v1.1: harden __copy_to_user
  ARM: 8796/1: spectre-v1,v1.1: provide helpers for address sanitization
  ARM: 8795/1: spectre-v1.1: use put_user() for __put_user()
  ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit
  ARM: 8793/1: signal: replace __put_user_error with __put_user
  ARM: 8792/1: oabi-compat: copy oabi events using __copy_to_user()
  ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state
  ARM: 8789/1: signal: copy registers using __copy_to_user()
  uapi/if_ether.h: prevent redefinition of struct ethhdr
  eeprom: at24: add support for 24c2048
  dt-bindings: eeprom: at24: add "atmel,24c2048" compatible string
  BACKPORT: userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas
  ANDROID: cuttlefish_defconfig: Enable DEBUG_SET_MODULE_RONX
  Linux 4.9.158
  Revert "exec: load_script: don't blindly truncate shebang string"
  Linux 4.9.157
  batman-adv: Force mac header to start of data on xmit
  batman-adv: Avoid WARN on net_device without parent in netns
  xfrm: refine validation of template and selector families
  libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive()
  Revert "cifs: In Kconfig CONFIG_CIFS_POSIX needs depends on legacy (insecure cifs)"
  HID: debug: fix the ring buffer implementation
  nfsd4: catch some false session retries
  nfsd4: fix cached replies to solo SEQUENCE compounds
  drm/vmwgfx: Return error code from vmw_execbuf_copy_fence_user
  drm/vmwgfx: Fix setting of dma masks
  drm/modes: Prevent division by zero htotal
  mac80211: ensure that mgmt tx skbs have tailroom for encryption
  ARM: tango: Improve ARCH_MULTIPLATFORM compatibility
  ARM: iop32x/n2100: fix PCI IRQ mapping
  MIPS: VDSO: Include $(ccflags-vdso) in o32,n32 .lds builds
  MIPS: OCTEON: don't set octeon_dma_bar_type if PCI is disabled
  mips: cm: reprime error cause
  debugfs: fix debugfs_rename parameter checking
  samples: mei: use /dev/mei0 instead of /dev/mei
  misc: vexpress: Off by one in vexpress_syscfg_exec()
  signal: Better detection of synchronous signals
  signal: Always notice exiting tasks
  iio: chemical: atlas-ph-sensor: correct IIO_TEMP values to millicelsius
  mtd: rawnand: gpmi: fix MX28 bus master lockup problem
  ANDROID: cuttlefish: enable CONFIG_NET_SCH_NETEM=y
  Add XFRM-I to cuttlefish defconfigs
  ANDROID: Move from clang r346389b to r349610.
  Linux 4.9.156
  ath9k: dynack: check da->enabled first in sampling routines
  ath9k: dynack: make ewma estimation faster
  perf/x86/intel: Delay memory deallocation until x86_pmu_dead_cpu()
  IB/hfi1: Add limit test for RC/UC send via loopback
  PCI: vmd: Free up IRQs on suspend path
  oom, oom_reaper: do not enqueue same task twice
  serial: fix race between flush_to_ldisc and tty_open
  perf tests evsel-tp-sched: Fix bitwise operator
  perf/core: Don't WARN() for impossible ring-buffer sizes
  x86/MCE: Initialize mce.bank in the case of a fatal error in mce_no_way_out()
  perf/x86/intel/uncore: Add Node ID mask
  KVM: nVMX: unconditionally cancel preemption timer in free_nested (CVE-2019-7221)
  kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974)
  KVM: x86: work around leak of uninitialized stack contents (CVE-2019-7222)
  scsi: aic94xx: fix module loading
  usb: gadget: musb: fix short isoc packets with inventra dma
  usb: gadget: udc: net2272: Fix bitwise and boolean operations
  usb: phy: am335x: fix race condition in _probe
  dmaengine: imx-dma: fix wrong callback invoke
  dmaengine: bcm2835: Fix abort of transactions
  dmaengine: bcm2835: Fix interrupt race on RT
  fuse: handle zero sized retrieve correctly
  fuse: decrement NR_WRITEBACK_TEMP on the right page
  fuse: call pipe_buf_release() under pipe lock
  ALSA: hda - Serialize codec registrations
  ALSA: compress: Fix stop handling on compressed capture streams
  enic: fix checksum validation for IPv6
  net: dsa: slave: Don't propagate flag changes on down slave interfaces
  net/mlx5e: Force CHECKSUM_UNNECESSARY for short ethernet frames
  net: systemport: Fix WoL with password after deep sleep
  rds: fix refcount bug in rds_sock_addref
  skge: potential memory corruption in skge_get_regs()
  rxrpc: bad unlock balance in rxrpc_recvmsg
  net: dp83640: expire old TX-skb
  dccp: fool proof ccid_hc_[rt]x_parse_options()
  thermal: hwmon: inline helpers when CONFIG_THERMAL_HWMON is not set
  exec: load_script: don't blindly truncate shebang string
  fs/epoll: drop ovflist branch prediction
  proc/sysctl: fix return error for proc_doulongvec_minmax()
  kernel/hung_task.c: break RCU locks based on jiffies
  HID: lenovo: Add checks to fix of_led_classdev_register
  thermal: generic-adc: Fix adc to temp interpolation
  block/swim3: Fix -EBUSY error when re-opening device after unmount
  fsl/fman: Use GFP_ATOMIC in {memac,tgec}_add_hash_mac_address()
  gdrom: fix a memory leak bug
  isdn: hisax: hfc_pci: Fix a possible concurrency use-after-free bug in HFCPCI_l1hw()
  ocfs2: don't clear bh uptodate for block read
  scripts/decode_stacktrace: only strip base path when a prefix of the path
  f2fs: fix sbi->extent_list corruption issue
  niu: fix missing checks of niu_pci_eeprom_read
  um: Avoid marking pages with "changed protection"
  cifs: check ntwrk_buf_start for NULL before dereferencing it
  MIPS: ralink: Select CONFIG_CPU_MIPSR2_IRQ_VI on MT7620/8
  crypto: ux500 - Use proper enum in hash_set_dma_transfer
  crypto: ux500 - Use proper enum in cryp_set_dma_transfer
  seq_buf: Make seq_buf_puts() null-terminate the buffer
  hwmon: (lm80) fix a missing check of bus read in lm80 probe
  hwmon: (lm80) fix a missing check of the status of SMBus read
  NFS: nfs_compare_mount_options always compare auth flavors.
  KVM: x86: svm: report MSR_IA32_MCG_EXT_CTL as unsupported
  pinctrl: meson: meson8b: fix the GPIO function for the GPIOAO pins
  pinctrl: meson: meson8: fix the GPIO function for the GPIOAO pins
  fbdev: fbcon: Fix unregister crash when more than one framebuffer
  igb: Fix an issue that PME is not enabled during runtime suspend
  i40e: define proper net_device::neigh_priv_len
  fbdev: fbmem: behave better with small rotated displays and many CPUs
  video: clps711x-fb: release disp device node in probe()
  drbd: Avoid Clang warning about pointless switch statment
  drbd: skip spurious timeout (ping-timeo) when failing promote
  drbd: disconnect, if the wrong UUIDs are attached on a connected peer
  drbd: narrow rcu_read_lock in drbd_sync_handshake
  cw1200: Fix concurrency use-after-free bugs in cw1200_hw_scan()
  scsi: smartpqi: correct volume status
  scsi: smartpqi: correct host serial num for ssa
  Bluetooth: Fix unnecessary error message for HCI request completion
  xfrm6_tunnel: Fix spi check in __xfrm6_tunnel_alloc_spi
  mac80211: fix radiotap vendor presence bitmap handling
  powerpc/uaccess: fix warning/error with access_ok()
  arm64: KVM: Skip MMIO insn after emulation
  perf probe: Fix unchecked usage of strncpy()
  perf header: Fix unchecked usage of strncpy()
  tty: serial: samsung: Properly set flags in autoCTS mode
  memstick: Prevent memstick host from getting runtime suspended during card detection
  ASoC: fsl: Fix SND_SOC_EUKREA_TLV320 build error on i.MX8M
  ARM: pxa: avoid section mismatch warning
  udf: Fix BUG on corrupted inode
  i2c-axxia: check for error conditions first
  cpuidle: big.LITTLE: fix refcount leak
  clk: imx6sl: ensure MMDC CH0 handshake is bypassed
  sata_rcar: fix deferred probing
  iommu/arm-smmu-v3: Use explicit mb() when moving cons pointer
  iommu/arm-smmu: Add support for qcom,smmu-v2 variant
  mips: bpf: fix encoding bug for mm_srlv32_op
  ARM: dts: Fix OMAP4430 SDP Ethernet startup
  iommu/amd: Fix amd_iommu=force_isolation
  clk: sunxi-ng: a33: Set CLK_SET_RATE_PARENT for all audio module clocks
  timekeeping: Use proper seqcount initializer
  usb: hub: delay hub autosuspend if USB3 port is still link training
  smack: fix access permissions for keyring
  media: DaVinci-VPBE: fix error handling in vpbe_initialize()
  x86/fpu: Add might_fault() to user_insn()
  ARM: dts: mmp2: fix TWSI2
  arm64: ftrace: don't adjust the LR value
  firmware/efi: Add NULL pointer checks in efivars API functions
  Thermal: do not clear passive state during system sleep
  nfsd4: fix crash on writing v4_end_grace before nfsd startup
  soc: bcm: brcmstb: Don't leak device tree node reference
  sunvdc: Do not spin in an infinite loop when vio_ldc_send() returns EAGAIN
  f2fs: fix wrong return value of f2fs_acl_create
  f2fs: move dir data flush to write checkpoint process
  media: adv*/tc358743/ths8200: fill in min width/height/pixelclock
  iio: accel: kxcjk1013: Add KIOX010A ACPI Hardware-ID
  dmaengine: xilinx_dma: Remove __aligned attribute on zynqmp_dma_desc_ll
  media: mtk-vcodec: Release device nodes in mtk_vcodec_init_enc_pm()
  soc/tegra: Don't leak device tree node reference
  perf tools: Add Hygon Dhyana support
  modpost: validate symbol names also in find_elf_symbol
  ARM: OMAP2+: hwmod: Fix some section annotations
  staging: iio: ad7780: update voltage on read
  staging:iio:ad2s90: Make probe handle spi_setup failure
  ptp: check gettime64 return code in PTP_SYS_OFFSET ioctl
  serial: fsl_lpuart: clear parity enable bit when disable parity
  drm/vc4: ->x_scaling[1] should never be set to VC4_SCALING_NONE
  powerpc/pseries: add of_node_put() in dlpar_detach_node()
  x86/PCI: Fix Broadcom CNB20LE unintended sign extension (redux)
  dlm: Don't swamp the CPU with callbacks queued during recovery
  ARM: 8808/1: kexec:offline panic_smp_self_stop CPU
  scsi: lpfc: Correct LCB RJT handling
  ath9k: dynack: use authentication messages for 'late' ack
  gpu: ipu-v3: image-convert: Prevent race between run and unprepare
  ASoC: Intel: mrfld: fix uninitialized variable access
  staging: iio: adc: ad7280a: handle error from __ad7280_read32()
  drm/bufs: Fix Spectre v1 vulnerability
  ANDROID: Turn xt_owner module on
  ANDROID: Remove xt_qtaguid module from new kernels.
  UPSTREAM: virt_wifi: fix error return code in virt_wifi_newlink()
  ion: Disable ION_HEAP_TYPE_SYSTEM_CONTIG
  ANDROID: arm64: lse: fix LSE atomics with LTO

Conflicts:
	arch/arm/kernel/setup.c
	drivers/iommu/arm-smmu.c
	drivers/thermal/thermal_core.c
	include/linux/sched.h
	mm/memory.c
	mm/oom_kill.c
	net/netfilter/xt_qtaguid.c

Change-Id: I8629ac12c19fb9d63b21b21431afc300b4f1568d
Signed-off-by: jianzhou <jianzhou@codeaurora.org>

jianzhou   commited 2019-03-21 14:06:06 +08:00
b7d9747d02
kernel/hung_task.c: break RCU locks based on jiffies
[ Upstream commit 304ae42739b108305f8d7b3eb3c1aec7c2b643a9 ]

check_hung_uninterruptible_tasks() is currently calling rcu_lock_break()
for every 1024 threads.  But check_hung_task() is very slow if printk()
was called, and is very fast otherwise.

If many threads within some 1024 threads called printk(), the RCU grace
period might be extended enough to trigger RCU stall warnings.
Therefore, calling rcu_lock_break() for every some fixed jiffies will be
safer.

Link: http://lkml.kernel.org/r/1544800658-11423-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Tetsuo Handa   authored and   Greg Kroah-Hartman   commited 2019-02-12 19:44:59 +01:00
629e457d16
hung task: check specific tasks for long uninterruptible sleep state
khungtask by default monitors all tasks for long unterruptible sleep.
This change introduces a sysctl option, /proc/sys/kernel/
hung_task_selective_monitoring, to enable monitoring selected tasks.
If this sysctl option is enabled then only the tasks with
/proc/$PID/hang_detection_enabled set are to be monitored,
otherwise all tasks are monitored as default case.

Some tasks may intentionally moves to uninterruptable sleep state,
which shouldn't leads to khungtask panics, as those are recoverable
hungs. So to avoid false hung reports, add an option to select tasks
to be monitored and report/panic them only.
By default, enable the feature always to monitor selected tasks.

Change-Id: I48cd8cfe73dbe2b577541fe9607190eac5556bb2
Signed-off-by: Imran Khan <kimran@codeaurora.org>
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>

Imran Khan   authored and   Lingutla Chandrasekhar   commited 2017-10-25 13:51:29 +05:30
a9788f4c9d
hung_task: allow hung_task_panic when hung_task_warnings is 0
Previously hung_task_panic would not be respected if enabled after
hung_task_warnings had already been decremented to 0.

Permit the kernel to panic if hung_task_panic is enabled after
hung_task_warnings has already been decremented to 0 and another task
hangs for hung_task_timeout_secs seconds.

Check if hung_task_panic is enabled so we don't return prematurely, and
check if hung_task_warnings is non-zero so we don't print the warning
unnecessarily.

[akpm@linux-foundation.org: fix off-by-one]
Link: http://lkml.kernel.org/r/1473450214-4049-1-git-send-email-jsiddle@redhat.com
Signed-off-by: John Siddle <jsiddle@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

John Siddle   authored and   Linus Torvalds   commited 2016-10-11 15:06:33 -07:00
48a6d64eda
locking/hung_task: Show all locks
When we get a hung task it can often be valuable to see _all_ the held
locks on the system (in case we are being blocked on trying to acquire
one), e.g. with this patch we can immediately see where the problem is
below:

    INFO: task trinity-c3:14933 blocked for more than 120 seconds.
	  Not tainted 4.8.0-rc1+ #135
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    trinity-c3      D ffff88010c16fc88     0 14933      1 0x00080004
     ffff88010c16fc88 000000003b9aca00 0000000000000000 0000000000000296
     00000000776cdf88 ffff88011a520ae0 ffff88011a520b08 ffff88011a520198
     ffffffff867d7f00 ffff88011942c080 ffff880116841580 ffff88010c168000
    Call Trace:
     [<ffffffff845e9d37>] schedule+0x77/0x230
     [<ffffffff833cb8b9>] __lock_sock+0x129/0x250
     [<ffffffff833cb790>] ? __sk_destruct+0x450/0x450
     [<ffffffff81408ac0>] ? wake_bit_function+0x2e0/0x2e0
     [<ffffffff833d832b>] lock_sock_nested+0xeb/0x120
     [<ffffffff83bad815>] irda_setsockopt+0x65/0xb40
     [<ffffffff833c6c09>] SyS_setsockopt+0x139/0x230
     [<ffffffff833c6ad0>] ? SyS_recv+0x20/0x20
     [<ffffffff81004660>] ? trace_event_raw_event_sys_enter+0xb90/0xb90
     [<ffffffff823c7023>] ? __this_cpu_preempt_check+0x13/0x20
     [<ffffffff8162ee60>] ? __context_tracking_exit.part.3+0x30/0x1b0
     [<ffffffff833c6ad0>] ? SyS_recv+0x20/0x20
     [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0
     [<ffffffff845f84aa>] entry_SYSCALL64_slow_path+0x25/0x25

    Showing all locks held in the system:
    2 locks held by khungtaskd/563:
     #0:  (rcu_read_lock){......}, at: [<ffffffff81534ce6>] watchdog+0x106/0x910
     #1:  (tasklist_lock){......}, at: [<ffffffff8141b3c4>] debug_show_all_locks+0x74/0x360
    1 lock held by trinity-c0/19280:
     #0:  (sk_lock-AF_IRDA){......}, at: [<ffffffff83bab7c6>] irda_accept+0x176/0x10f0
    1 lock held by trinity-c0/12865:
     #0:  (sk_lock-AF_IRDA){......}, at: [<ffffffff83bab7c6>] irda_accept+0x176/0x10f0

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471538460-7505-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Vegard Nossum   authored and   Ingo Molnar   commited 2016-08-24 12:16:13 +02:00
b2d4c2edb2
kernel/hung_task.c: use timeout diff when timeout is updated
When new timeout is written to /proc/sys/kernel/hung_task_timeout_secs,
khungtaskd is interrupted and again sleeps for full timeout duration.

This means that hang task will not be checked if new timeout is written
periodically within old timeout duration and/or checking of hang task
will be delayed for up to previous timeout duration.  Fix this by
remembering last time khungtaskd checked hang task.

This change will allow other watchdog tasks (if any) to share khungtaskd
by sleeping for minimal timeout diff of all watchdog tasks.  Doing more
watchdog tasks from khungtaskd will reduce the possibility of printk()
collisions by multiple watchdog threads.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Tetsuo Handa   authored and   Linus Torvalds   commited 2016-03-22 15:36:02 -07:00
b4aa14a63c
kernel/hung_task.c: change hung_task.c to use for_each_process_thread()
In check_hung_uninterruptible_tasks() avoid the use of deprecated
while_each_thread().

The "max_count" logic will prevent a livelock - see commit 0c740d0a
("introduce for_each_thread() to replace the buggy while_each_thread()").
Having said this let's use for_each_process_thread().

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Wysochanski <dwysocha@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Aaron Tomlin   authored and   Linus Torvalds   commited 2015-04-15 16:35:22 -07:00
972fae6993
kernel/hung_task.c: convert simple_strtoul to kstrtouint
sysctl_hung_task_panic has been changed to unsigned int.  use kstrtouint
instead of obsolete simple_strtoul

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fabian Frederick   authored and   Linus Torvalds   commited 2014-06-04 16:54:15 -07:00
b51dbec68c
kernel: audit/fix non-modular users of module_init in core code
Code that is obj-y (always built-in) or dependent on a bool Kconfig
(built-in or absent) can never be modular.  So using module_init as an
alias for __initcall can be somewhat misleading.

Fix these up now, so that we can relocate module_init from init.h into
module.h in the future.  If we don't do this, we'd have to add module.h
to obviously non-modular code, and that would be a worse thing.

The audit targets the following module_init users for change:
 kernel/user.c                  obj-y
 kernel/kexec.c                 bool KEXEC (one instance per arch)
 kernel/profile.c               bool PROFILING
 kernel/hung_task.c             bool DETECT_HUNG_TASK
 kernel/sched/stats.c           bool SCHEDSTATS
 kernel/user_namespace.c        bool USER_NS

Note that direct use of __initcall is discouraged, vs.  one of the
priority categorized subgroups.  As __initcall gets mapped onto
device_initcall, our use of subsys_initcall (which makes sense for these
files) will thus change this registration from level 6-device to level
4-subsys (i.e.  slightly earlier).  However no observable impact of that
difference has been observed during testing.

Also, two instances of missing ";" at EOL are fixed in kexec.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Paul Gortmaker   authored and   Linus Torvalds   commited 2014-04-03 16:21:07 -07:00
c96d6660dc
hung_task: Display every hung task warning
When khungtaskd detects hung tasks, it prints out
backtraces from a number of those tasks.

Limiting the number of backtraces being printed
out can result in the user not seeing the information
necessary to debug the issue. The hung_task_warnings
sysctl controls this feature.

This patch makes it possible for hung_task_warnings
to accept a special value to print an unlimited
number of backtraces when khungtaskd detects hung
tasks.

The special value is -1. To use this value it is
necessary to change types from ulong to int.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1390239253-24030-3-git-send-email-atomlin@redhat.com
[ Build warning fix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Aaron Tomlin   authored and   Ingo Molnar   commited 2014-01-25 12:13:33 +01:00
270750dbc1
Here are the 3.13 KVM changes. There was a lot of work on the PPC
side: the HV and emulation flavors can now coexist in a single kernel
 is probably the most interesting change from a user point of view.
 On the x86 side there are nested virtualization improvements and a
 few bugfixes.  ARM got transparent huge page support, improved
 overcommit, and support for big endian guests.
 
 Finally, there is a new interface to connect KVM with VFIO.  This
 helps with devices that use NoSnoop PCI transactions, letting the
 driver in the guest execute WBINVD instructions.  This includes
 some nVidia cards on Windows, that fail to start without these
 patches and the corresponding userspace changes.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM changes from Paolo Bonzini:
 "Here are the 3.13 KVM changes.  There was a lot of work on the PPC
  side: the HV and emulation flavors can now coexist in a single kernel
  is probably the most interesting change from a user point of view.

  On the x86 side there are nested virtualization improvements and a few
  bugfixes.

  ARM got transparent huge page support, improved overcommit, and
  support for big endian guests.

  Finally, there is a new interface to connect KVM with VFIO.  This
  helps with devices that use NoSnoop PCI transactions, letting the
  driver in the guest execute WBINVD instructions.  This includes some
  nVidia cards on Windows, that fail to start without these patches and
  the corresponding userspace changes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits)
  kvm, vmx: Fix lazy FPU on nested guest
  arm/arm64: KVM: PSCI: propagate caller endianness to the incoming vcpu
  arm/arm64: KVM: MMIO support for BE guest
  kvm, cpuid: Fix sparse warning
  kvm: Delete prototype for non-existent function kvm_check_iopl
  kvm: Delete prototype for non-existent function complete_pio
  hung_task: add method to reset detector
  pvclock: detect watchdog reset at pvclock read
  kvm: optimize out smp_mb after srcu_read_unlock
  srcu: API for barrier after srcu read unlock
  KVM: remove vm mmap method
  KVM: IOMMU: hva align mapping page size
  KVM: x86: trace cpuid emulation when called from emulator
  KVM: emulator: cleanup decode_register_operand() a bit
  KVM: emulator: check rex prefix inside decode_register()
  KVM: x86: fix emulation of "movzbl %bpl, %eax"
  kvm_host: typo fix
  KVM: x86: emulate SAHF instruction
  MAINTAINERS: add tree for kvm.git
  Documentation/kvm: add a 00-INDEX file
  ...

Linus Torvalds   commited 2013-11-15 13:51:36 +09:00
f080480488
hung_task: add method to reset detector
In certain occasions it is possible for a hung task detector
positive to be false: continuation from a paused VM, for example.

Add a method to reset detection, similar as is done
with other kernel watchdogs.

Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

Marcelo Tosatti   authored and   Gleb Natapov   commited 2013-11-06 09:49:02 +02:00
8b414521bc
hung_task debugging: Add tracepoint to report the hang
Currently check_hung_task() prints a warning if it detects the
problem, but it is not convenient to watch the system logs if
user-space wants to be notified about the hang.

Add the new trace_sched_process_hang() into check_hung_task(),
this way a user-space monitor can easily wait for the hang and
potentially resolve a problem.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Dave Sullivan <dsulliva@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20131019161828.GA7439@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Oleg Nesterov   authored and   Ingo Molnar   commited 2013-10-31 11:16:18 +01:00
6a716c90a5
hung_task: Change sysctl_hung_task_check_count to 'int'
As 'sysctl_hung_task_check_count' is 'unsigned long' when this
value is assigned to max_count in check_hung_uninterruptible_tasks(),
it's truncated to 'int' type.

This causes a minor artifact: if we write 2^32 to sysctl.hung_task_check_count,
hung task detection will be effectively disabled.

With this fix, it will still truncate the user input to 32 bits, but
reading sysctl.hung_task_check_count reflects the actual truncated value.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/523FFF4E.9050401@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Li Zefan   authored and   Ingo Molnar   commited 2013-09-23 11:10:49 +02:00
cd64647f04
hung_task debugging: Print more info when reporting the problem
printk(KERN_ERR) from check_hung_task() likely means we have a bug,
but unlike BUG_ON()/WARN_ON ()it doesn't show the kernel version,
this complicates the bug-reports investigation.

Add the additional pr_err() to print tainted/release/version
like dump_stack_print_info() does, the output becomes:

        INFO: task perl:504 blocked for more than 2 seconds.
	      Not tainted 3.11.0-rc1-10367-g136bb46-dirty #1763
        "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
        ...

While at it, turn the old printk's into pr_err().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: ahecox@redhat.com
Cc: Christopher Williams <cww@redhat.com>
Cc: dwysocha@redhat.com
Cc: gavin@redhat.com
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: nshi@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20130801165941.GA17544@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Oleg Nesterov   authored and   Ingo Molnar   commited 2013-08-02 11:02:42 +02:00
41e85ce822
hung task debugging: Inject NMI when hung and going to panic
Send an NMI to all CPUs when a hung task is detected and the hung
task code is configured to panic. This gives us a fairly uptodate
snapshot of all CPUs in the system.

This lets us get stack trace of all CPUs which makes life easier
trying to debug a deadlock, and the NMI doesn't change anything
since the next step is a kernel panic.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1331848040-1676-1-git-send-email-levinsasha928@gmail.com
[ extended the changelog a bit ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Sasha Levin   authored and   Ingo Molnar   commited 2012-04-25 12:39:25 +02:00
625056b65e
hung_task: fix the broken rcu_lock_break() logic
check_hung_uninterruptible_tasks()->rcu_lock_break() introduced by
"softlockup: check all tasks in hung_task" commit ce9dbe24 looks
absolutely wrong.

	- rcu_lock_break() does put_task_struct(). If the task has exited
	  it is not safe to even read its ->state, nothing protects this
	  task_struct.

	- The TASK_DEAD checks are wrong too. Contrary to the comment, we
	  can't use it to check if the task was unhashed. It can be unhashed
	  without TASK_DEAD, or it can be valid with TASK_DEAD.

	  For example, an autoreaping task can do release_task(current)
	  long before it sets TASK_DEAD in do_exit().

	  Or, a zombie task can have ->state == TASK_DEAD but release_task()
	  was not called, and in this case we must not break the loop.

Change this code to check pid_alive() instead, and do this before we drop
the reference to the task_struct.

Note: while_each_thread() under rcu_read_lock() is not really safe, it can
livelock.  This will be fixed later, but fortunately in this case the
"max_count" logic saves us anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Oleg Nesterov   authored and   Linus Torvalds   commited 2012-03-05 15:49:42 -08:00
6027ce497d
hung_task: fix false positive during vfork
vfork parent uninterruptibly and unkillably waits for its child to
exec/exit. This wait is of unbounded length. Ignore such waits
in the hung_task detector.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Reported-by: Sasha Levin <levinsasha928@gmail.com>
LKML-Reference: <1325344394.28904.43.camel@lappy>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Mandeep Singh Baines   authored and   Linus Torvalds   commited 2012-01-03 16:14:32 -08:00
f9fab10bbd
kernel: Map most files to use export.h instead of module.h
The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include <linux/module.h>
  +#include <linux/export.h>

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Paul Gortmaker   commited 2011-10-31 09:20:12 -04:00
9984de1a5a
watchdog, hung_task_timeout: Add Kconfig configurable default
This patch allows the default value for sysctl_hung_task_timeout_secs
to be set at build time. The feature carries virtually no overhead,
so it makes sense to keep it enabled. On heavily loaded systems, though,
it can end up triggering stack traces when there is no bug other than
the system being underprovisioned. We use this patch to keep the hung task
facility available but disabled at boot-time.

The default of 120 seconds is preserved. As a note, commit e162b39a may
have accidentally reverted commit fb822db4, which raised the default from
120 seconds to 480 seconds.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Link: http://lkml.kernel.org/r/4DB8600C.8080000@suse.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Jeff Mahoney   authored and   Ingo Molnar   commited 2011-04-28 09:13:17 +02:00
e11feaa119
lockup detector: Fix grammar by adding a missing "to" in the comments
This fixes a minor grammar problem in the comments in
hung_task.c

Signed-off-by: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1281021054-4228-2-git-send-email-jkacur@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

John Kacur   authored and   Ingo Molnar   commited 2010-08-17 09:11:52 +02:00
6a103b0d44
lockdep: Remove __debug_show_held_locks
There is no longer any functional difference between
__debug_show_held_locks() and debug_show_held_locks(),
so remove the former.

Signed-off-by: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1281021054-4228-1-git-send-email-jkacur@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

John Kacur   authored and   Ingo Molnar   commited 2010-08-17 09:11:10 +02:00
f1b499f029
softlockup: Fix hung_task_check_count sysctl
I'm seeing spikes of up to 0.5ms in khungtaskd on a large
machine. To reduce this source of jitter I tried setting
hung_task_check_count to 0:

 # echo 0 > /proc/sys/kernel/hung_task_check_count

which didn't have the intended response. Change to a post
increment of max_count, so a value of 0 means check 0 tasks.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: msb@google.com
LKML-Reference: <20091127022820.GU32182@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Anton Blanchard   authored and   Ingo Molnar   commited 2009-11-27 06:21:57 +01:00
e5af022616
sysctl: remove "struct file *" argument of ->proc_handler
It's unused.

It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.

It _was_ used in two places at arch/frv for some reason.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Alexey Dobriyan   authored and   Linus Torvalds   commited 2009-09-24 07:21:04 -07:00
8d65af789f
softlockup: ensure the task has been switched out once
When we check if a task has been switched out since the last scan, we might
have a race condition on the following scenario:

- the task is freshly created and scheduled

- it puts its state to TASK_UNINTERRUPTIBLE and is not yet switched out

- check_hung_task() scans this task and will report a false positive because
  t->nvcsw + t->nivcsw == t->last_switch_count == 0

Add a check for such cases.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Frederic Weisbecker   authored and   Ingo Molnar   commited 2009-02-11 11:04:16 +01:00
cf2592f59c
softlockup: remove timestamp checking from hung_task
Impact: saves sizeof(long) bytes per task_struct

By guaranteeing that sysctl_hung_task_timeout_secs have elapsed between
tasklist scans we can avoid using timestamps.

Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Mandeep Singh Baines   authored and   Ingo Molnar   commited 2009-02-09 11:03:49 +01:00
17406b82d6
softlockup: convert read_lock in hung_task to rcu_read_lock
Since the tasklist is protected by rcu list operations, it is safe
to convert the read_lock()s to rcu_read_lock().

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Mandeep Singh Baines   authored and   Ingo Molnar   commited 2009-02-05 19:55:31 +01:00
94be52dc07
softlockup: check all tasks in hung_task
Impact: extend the scope of hung-task checks

Changed the default value of hung_task_check_count to PID_MAX_LIMIT.
hung_task_batch_count added to put an upper bound on the critical
section. Every hung_task_batch_count checks, the rcu lock is never
held for a too long time.

Keeping the critical section small minimizes time preemption is disabled
and keeps rcu grace periods small.

To prevent following a stale pointer, get_task_struct is called on g and t.
To verify that g and t have not been unhashed while outside the critical
section, the task states are checked.

The design was proposed by Frédéric Weisbecker.

Signed-off-by: Mandeep Singh Baines <msb@google.com>
Suggested-by: Frédéric Weisbecker <fweisbec@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Mandeep Singh Baines   authored and   Ingo Molnar   commited 2009-02-05 19:54:57 +01:00
ce9dbe244b
softlockup: fix potential race in hung_task when resetting timeout
Impact: fix potential false panic

A potential race exists if sysctl_hung_task_timeout_secs is reset to 0
while inside check_hung_uniterruptible_tasks(). If check_task() is
entered, a comparison with 0 will result in a false hung_task being
detected.

If sysctl_hung_task_panic is set, the system will panic.

Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Mandeep Singh Baines   authored and   Ingo Molnar   commited 2009-01-18 19:20:17 +01:00
603a148f43
softlockup: decouple hung tasks check from softlockup detection
Decoupling allows:

* hung tasks check to happen at very low priority

* hung tasks check and softlockup to be enabled/disabled independently
  at compile and/or run-time

* individual panic settings to be enabled disabled independently
  at compile and/or run-time

* softlockup threshold to be reduced without increasing hung tasks
  poll frequency (hung task check is expensive relative to softlock watchdog)

* hung task check to be zero over-head when disabled at run-time

Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Mandeep Singh Baines   authored and   Ingo Molnar   commited 2009-01-16 14:06:04 +01:00
e162b39a36