Commit graph android_kernel_sony_sdm845/kernel/workqueue.c
Message SHA1
Merge remote-tracking branch '4.9/tmp-4b2b8b9' into msm-4.9
* 4.9/tmp-4b2b8b9:
  Linux 4.9.60
  ecryptfs: fix dereference of NULL user_key_payload
  regulator: fan53555: fix I2C device ids
  ipsec: Fix aborted xfrm policy dump crash
  cfg80211: fix connect/disconnect edge cases
  can: kvaser_usb: Ignore CMD_FLUSH_QUEUE_REPLY messages
  can: kvaser_usb: Correct return value in printout
  can: sun4i: fix loopback mode
  drm/amd/powerplay: fix uninitialized variable
  scsi: sg: Re-fix off by one in sg_fill_request_table()
  scsi: zfcp: fix erp_action use-before-initialize in REC action trace
  assoc_array: Fix a buggy node-splitting case
  Input: gtco - fix potential out-of-bound access
  Input: elan_i2c - add ELAN0611 to the ACPI table
  xen/gntdev: avoid out of bounds access in case of partial gntdev_mmap()
  fuse: fix READDIRPLUS skipping an entry
  spi: bcm-qspi: Fix use after free in bcm_qspi_probe() in error path
  spi: uapi: spidev: add missing ioctl header
  KVM: PPC: Fix oops when checking KVM_CAP_PPC_HTM
  usb: xhci: Handle error condition in xhci_stop_device()
  ceph: unlock dangling spinlock in try_flush_caps()
  ALSA: hda - fix headset mic problem for Dell machines with alc236
  ALSA: hda/realtek - Add support for ALC236/ALC3204
  workqueue: replace pool->manager_arb mutex with a flag

Conflicts:
	drivers/usb/host/xhci-hub.c

Change-Id: I6de307270a5b951e4fb5c9ee62781a7b4f206b26
Signed-off-by: Kyle Yan <kyan@codeaurora.org>

Kyle Yan   commited 2017-11-05 14:31:07 -08:00
07f9309c8d
workqueue: replace pool->manager_arb mutex with a flag
commit 692b48258dda7c302e777d7d5f4217244478f1f6 upstream.

Josef reported a HARDIRQ-safe -> HARDIRQ-unsafe lock order detected by
lockdep:

 [ 1270.472259] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
 [ 1270.472783] 4.14.0-rc1-xfstests-12888-g76833e8 #110 Not tainted
 [ 1270.473240] -----------------------------------------------------
 [ 1270.473710] kworker/u5:2/5157 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
 [ 1270.474239]  (&(&lock->wait_lock)->rlock){+.+.}, at: [<ffffffff8da253d2>] __mutex_unlock_slowpath+0xa2/0x280
 [ 1270.474994]
 [ 1270.474994] and this task is already holding:
 [ 1270.475440]  (&pool->lock/1){-.-.}, at: [<ffffffff8d2992f6>] worker_thread+0x366/0x3c0
 [ 1270.476046] which would create a new lock dependency:
 [ 1270.476436]  (&pool->lock/1){-.-.} -> (&(&lock->wait_lock)->rlock){+.+.}
 [ 1270.476949]
 [ 1270.476949] but this new dependency connects a HARDIRQ-irq-safe lock:
 [ 1270.477553]  (&pool->lock/1){-.-.}
 ...
 [ 1270.488900] to a HARDIRQ-irq-unsafe lock:
 [ 1270.489327]  (&(&lock->wait_lock)->rlock){+.+.}
 ...
 [ 1270.494735]  Possible interrupt unsafe locking scenario:
 [ 1270.494735]
 [ 1270.495250]        CPU0                    CPU1
 [ 1270.495600]        ----                    ----
 [ 1270.495947]   lock(&(&lock->wait_lock)->rlock);
 [ 1270.496295]                                local_irq_disable();
 [ 1270.496753]                                lock(&pool->lock/1);
 [ 1270.497205]                                lock(&(&lock->wait_lock)->rlock);
 [ 1270.497744]   <Interrupt>
 [ 1270.497948]     lock(&pool->lock/1);

, which will cause a irq inversion deadlock if the above lock scenario
happens.

The root cause of this safe -> unsafe lock order is the
mutex_unlock(pool->manager_arb) in manage_workers() with pool->lock
held.

Unlocking mutex while holding an irq spinlock was never safe and this
problem has been around forever but it never got noticed because the
only time the mutex is usually trylocked while holding irqlock making
actual failures very unlikely and lockdep annotation missed the
condition until the recent b9c16a0e1f73 ("locking/mutex: Fix
lockdep_assert_held() fail").

Using mutex for pool->manager_arb has always been a bit of stretch.
It primarily is an mechanism to arbitrate managership between workers
which can easily be done with a pool flag.  The only reason it became
a mutex is that pool destruction path wants to exclude parallel
managing operations.

This patch replaces the mutex with a new pool flag POOL_MANAGER_ACTIVE
and make the destruction path wait for the current manager on a wait
queue.

v2: Drop unnecessary flag clearing before pool destruction as
    suggested by Boqun.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tejun Heo   authored and   Greg Kroah-Hartman   commited 2017-11-02 09:49:12 +01:00
43a980a996
Merge remote-tracking branch '4.9/tmp-85e1c01' into 4.9
* 4.9/tmp-85e1c01:
  Linux 4.9.48
  epoll: fix race between ep_poll_callback(POLLFREE) and ep_free()/ep_remove()
  kvm: arm/arm64: Force reading uncached stage2 PGD
  drm/ttm: Fix accounting error when fail to get pages for pool
  xfrm: policy: check policy direction value
  lib/mpi: kunmap after finishing accessing buffer
  wl1251: add a missing spin_lock_init()
  CIFS: remove endian related sparse warning
  CIFS: Fix maximum SMB2 header size
  alpha: uapi: Add support for __SANE_USERSPACE_TYPES__
  cpuset: Fix incorrect memory_pressure control file mapping
  cpumask: fix spurious cpumask_of_node() on non-NUMA multi-node configs
  ceph: fix readpage from fscache
  mm, madvise: ensure poisoned pages are removed from per-cpu lists
  mm, uprobes: fix multiple free of ->uprobes_state.xol_area
  crypto: algif_skcipher - only call put_page on referenced and used pages
  i2c: ismt: Return EMSGSIZE for block reads with bogus length
  i2c: ismt: Don't duplicate the receive length for block reads
  irqchip: mips-gic: SYNC after enabling GIC region
  ANDROID: fiq_debugger: Fix minor bug in code
  ANDROID: configs: remove requirement for CONFIG_SYNC
  FROMLIST: binder: fix an ret value override
  FROMLIST: binder: fix memory corruption in binder_transaction binder
  Linux 4.9.47
  lz4: fix bogus gcc warning
  scsi: sg: reset 'res_in_use' after unlinking reserved array
  scsi: sg: protect accesses to 'reserved' page array
  locking/spinlock/debug: Remove spinlock lockup detection code
  arm64: fpsimd: Prevent registers leaking across exec
  x86/io: Add "memory" clobber to insb/insw/insl/outsb/outsw/outsl
  arm64: mm: abort uaccess retries upon fatal signal
  kvm: arm/arm64: Fix race in resetting stage2 PGD
  gcov: support GCC 7.1
  staging: wilc1000: simplify vif[i]->ndev accesses
  scsi: isci: avoid array subscript warning
  p54: memset(0) whole array
  FROMLIST: android: binder: Add page usage in binder stats
  FROMLIST: android: binder: Add shrinker tracepoints
  FROMLIST: android: binder: Add global lru shrinker to binder
  FROMLIST: android: binder: Move buffer out of area shared with user space
  FROMLIST: android: binder: Add allocator selftest
  FROMLIST: android: binder: Refactor prev and next buffer into a helper function
  android: android-base.config: enable IP6_NF_MATCH_RPFILTER
  Linux 4.9.46
  powerpc/mm: Ensure cpumask update is ordered
  ACPI: EC: Fix regression related to wrong ECDT initialization order
  ACPI / APEI: Add missing synchronize_rcu() on NOTIFY_SCI removal
  ACPI: ioapic: Clear on-stack resource before using it
  ntb: transport shouldn't disable link due to bogus values in SPADs
  ntb: ntb_test: ensure the link is up before trying to configure the mws
  ntb: no sleep in ntb_async_tx_submit
  NTB: ntb_test: fix bug printing ntb_perf results
  ntb_transport: fix bug calculating num_qps_mw
  ntb_transport: fix qp count bug
  Clarify (and fix) MAX_LFS_FILESIZE macros
  staging: rtl8188eu: add RNX-N150NUB support
  iio: hid-sensor-trigger: Fix the race with user space powering up sensors
  iio: imu: adis16480: Fix acceleration scale factor for adis16480
  ANDROID: binder: fix proc->tsk check.
  binder: Use wake up hint for synchronous transactions.
  binder: use group leader instead of open thread
  Revert "android: binder: Sanity check at binder ioctl"
  Bluetooth: bnep: fix possible might sleep error in bnep_session
  Bluetooth: cmtp: fix possible might sleep error in cmtp_session
  Bluetooth: hidp: fix possible might sleep error in hidp_session_thread
  netfilter: nat: fix src map lookup
  Revert "leds: handle suspend/resume in heartbeat trigger"
  net: sunrpc: svcsock: fix NULL-pointer exception
  x86/mm: Fix use-after-free of ldt_struct
  timers: Fix excessive granularity of new timers after a nohz idle
  perf/x86/intel/rapl: Make package handling more robust
  perf probe: Fix --funcs to show correct symbols for offline module
  perf/core: Fix group {cpu,task} validation
  ftrace: Check for null ret_stack on profile function graph entry function
  nfsd: Limit end of page list when decoding NFSv4 WRITE
  cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup()
  cifs: Fix df output for users with quota limits
  kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured
  tracing: Fix freeing of filter in create_filter() when set_str is false
  tracing: Fix kmemleak in tracing_map_array_free()
  tracing: Call clear_boot_tracer() at lateinit_sync
  drm: rcar-du: Fix H/V sync signal polarity configuration
  drm: rcar-du: Fix display timing controller parameter
  drm: rcar-du: Fix crash in encoder failure error path
  drm/atomic: If the atomic check fails, return its value first
  drm: Release driver tracking before making the object available again
  mm/memblock.c: reversed logic in memblock_discard()
  fork: fix incorrect fput of ->exe_file causing use-after-free
  mm/madvise.c: fix freeing of locked page with MADV_FREE
  i2c: designware: Fix system suspend
  mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled
  ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses
  ALSA: firewire: fix NULL pointer dereference when releasing uninitialized data of iso-resource
  ALSA: hda - Add stereo mic quirk for Lenovo G50-70 (17aa:3978)
  ALSA: core: Fix unexpected error at replacing user TLV
  ALSA: usb-audio: Add delay quirk for H650e/Jabra 550a USB headsets
  KVM: x86: block guest protection keys unless the host has them enabled
  KVM: s390: sthyi: fix specification exception detection
  KVM: s390: sthyi: fix sthyi inline assembly
  Input: ALPS - fix two-finger scroll breakage in right side on ALPS touchpad
  Input: elan_i2c - add ELAN0602 ACPI ID to support Lenovo Yoga310
  Input: trackpoint - add new trackpoint firmware ID
  bpf/verifier: fix min/max handling in BPF_SUB
  bpf: fix mixed signed/unsigned derived min/max value bounds
  bpf, verifier: fix alu ops against map_value{, _adj} register types
  bpf: adjust verifier heuristics
  bpf, verifier: add additional patterns to evaluate_reg_imm_alu
  net_sched: fix order of queue length updates in qdisc_replace()
  net: sched: fix NULL pointer dereference when action calls some targets
  irda: do not leak initialized list.dev to userspace
  net/mlx4_core: Enable 4K UAR if SRIOV module parameter is not enabled
  tcp: when rearming RTO, if RTO time is in past then fire RTO ASAP
  ipv6: repair fib6 tree in failure case
  ipv6: reset fn->rr_ptr when replacing route
  tipc: fix use-after-free
  sctp: fully initialize the IPv6 address in sctp_v6_to_addr()
  nfp: fix infinite loop on umapping cleanup
  ipv4: better IP_MAX_MTU enforcement
  ptr_ring: use kmalloc_array()
  openvswitch: fix skb_panic due to the incorrect actions attrlen
  bpf: fix bpf_trace_printk on 32 bit archs
  net_sched: remove warning from qdisc_hash_add
  net_sched/sfq: update hierarchical backlog when drop packet
  ipv4: fix NULL dereference in free_fib_info_rcu()
  dccp: defer ccid_hc_tx_delete() at dismantle time
  dccp: purge write queue in dccp_destroy_sock()
  af_key: do not use GFP_KERNEL in atomic contexts
  sparc64: remove unnecessary log message
  ANDROID: NFC: st21nfca: Fix memory OOB and leak issues in connectivity events handler
  Linux 4.9.45
  usb: qmi_wwan: add D-Link DWM-222 device ID
  usb: optimize acpi companion search for usb port devices
  pids: make task_tgid_nr_ns() safe
  Sanitize 'move_pages()' permission checks
  genirq/ipi: Fixup checks against nr_cpu_ids
  genirq: Restore trigger settings in irq_modify_status()
  irqchip/atmel-aic: Fix unbalanced refcount in aic_common_rtc_irq_fixup()
  irqchip/atmel-aic: Fix unbalanced of_node_put() in aic_common_irq_fixup()
  x86/asm/64: Clear AC on NMI entries
  xen-blkfront: use a right index when checking requests
  powerpc: Fix VSX enabling/flushing to also test MSR_FP and MSR_VEC
  blk-mq-pci: add a fallback when pci_irq_get_affinity returns NULL
  xen: fix bio vec merging
  mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes
  mm/mempolicy: fix use after free when calling get_mempolicy
  mm: fix double mmap_sem unlock on MMF_UNSTABLE enforced SIGBUS
  mm: discard memblock data later
  ALSA: usb-audio: Add mute TLV for playback volumes on C-Media devices
  ALSA: usb-audio: Apply sample rate quirk to Sennheiser headset
  ALSA: seq: 2nd attempt at fixing race creating a queue
  Input: elan_i2c - Add antoher Lenovo ACPI ID for upcoming Lenovo NB
  Input: elan_i2c - add ELAN0608 to the ACPI table
  crypto: x86/sha1 - Fix reads beyond the number of blocks passed
  crypto: ixp4xx - Fix error handling path in 'aead_perform()'
  parisc: pci memory bar assignment fails with 64bit kernels on dino/cujo
  audit: Fix use after free in audit_remove_watch_rule()
  netfilter: nf_ct_ext: fix possible panic after nf_ct_extend_unregister
  ANDROID: check dir value of xfrm_userpolicy_id
  ANDROID: NFC: Fix possible memory corruption when handling SHDLC I-Frame commands
  ANDROID: nfc: fdp: Fix possible buffer overflow in WCS4000 NFC driver
  ANDROID: NFC: st21nfca: Fix out of bounds kernel access when handling ATR_REQ
  ANDROID: usb: gadget: assign no-op request complete callbacks
  ANDROID: usb: gadget: configfs: fix null ptr in android_disconnect
  ANDROID: uid_sys_stats: Fix implicit declaration of get_cmdline()
  uid_sys_stats: log task io with a debug flag
  Linux 4.9.44
  MIPS: DEC: Fix an int-handler.S CPU_DADDI_WORKAROUNDS regression
  pinctrl: meson-gxbb: Add missing GPIODV_18 pin entry
  pinctrl: samsung: Remove bogus irq_[un]mask from resource management
  pinctrl: uniphier: fix WARN_ON() of pingroups dump on LD20
  pinctrl: uniphier: fix WARN_ON() of pingroups dump on LD11
  pinctrl: intel: merrifield: Correct UART pin lists
  pinctrl: sunxi: add a missing function of A10/A20 pinctrl driver
  pnfs/blocklayout: require 64-bit sector_t
  iio: adc: vf610_adc: Fix VALT selection value for REFSEL bits
  usb:xhci:Add quirk for Certain failing HP keyboard on reset after resume
  usb: quirks: Add no-lpm quirk for Moshi USB to Ethernet Adapter
  usb: core: unlink urbs from the tail of the endpoint's urb_list
  USB: Check for dropped connection before switching to full speed
  usb: renesas_usbhs: Fix UGCTRL2 value for R-Car Gen3
  usb: gadget: udc: renesas_usb3: Fix usb_gadget_giveback_request() calling
  uas: Add US_FL_IGNORE_RESIDUE for Initio Corporation INIC-3069
  staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING
  iio: light: tsl2563: use correct event code
  iio: accel: bmc150: Always restore device to normal mode after suspend-resume
  staging:iio:resolver:ad2s1210 fix negative IIO_ANGL_VEL read
  USB: hcd: Mark secondary HCD as dead if the primary one died
  usb: musb: fix tx fifo flush handling again
  USB: serial: pl2303: add new ATEN device id
  USB: serial: cp210x: add support for Qivicon USB ZigBee dongle
  USB: serial: option: add D-Link DWM-222 device ID
  drm/i915: Fix out-of-bounds array access in bdw_load_gamma_lut
  drm/etnaviv: Fix off-by-one error in reloc checking
  nfs/flexfiles: fix leak of nfs4_ff_ds_version arrays
  mmc: mmc: correct the logic for setting HS400ES signal voltage
  nand: fix wrong default oob layout for small pages using soft ecc
  fuse: initialize the flock flag in fuse_file on allocation
  target: Fix node_acl demo-mode + uncached dynamic shutdown regression
  iscsi-target: Fix iscsi_np reset hung task during parallel delete
  iscsi-target: fix memory leak in iscsit_setup_text_cmd()
  mtd: nand: Fix timing setup for NANDs that do not support SET FEATURES
  xtensa: don't limit csum_partial export by CONFIG_NET
  xtensa: mm/cache: add missing EXPORT_SYMBOLs
  xtensa: fix cache aliasing handling code for WT cache
  futex: Remove unnecessary warning from get_futex_key
  mm: fix list corruptions on shmem shrinklist
  mm: ratelimit PFNs busy info message
  ANDROID: Use sk_uid to replace uid get from socket file
  Linux 4.9.43
  Revert "ARM: dts: sun8i: Support DTB build for NanoPi M1"
  KVM: arm/arm64: Handle hva aging while destroying the vm
  sparc64: Prevent perf from running during super critical sections
  udp: consistently apply ufo or fragmentation
  revert "ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output"
  revert "net: account for current skb length when deciding about UFO"
  packet: fix tp_reserve race in packet_set_ring
  igmp: Fix regression caused by igmp sysctl namespace code.
  net: avoid skb_warn_bad_offload false positives on UFO
  tcp: fastopen: tcp_connect() must refresh the route
  net: sched: set xt_tgchk_param par.nft_compat as 0 in ipt_init_target
  net/mlx4_en: don't set CHECKSUM_COMPLETE on SCTP packets
  bpf, s390: fix jit branch offset related to ldimm64
  net: fix keepalive code vs TCP_FASTOPEN_CONNECT
  tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states
  ppp: fix xmit recursion detection on ppp channels
  ppp: Fix false xmit recursion detect with two ppp devices
  Linux 4.9.42
  workqueue: implicit ordered attribute should be overridable
  net: phy: Fix PHY unbind crash
  net: account for current skb length when deciding about UFO
  ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output
  net/mlx5: E-Switch, Re-enable RoCE on mode change only after FDB destroy
  mm: don't dereference struct page fields of invalid pages
  signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
  lib/Kconfig.debug: fix frv build failure
  mm, slab: make sure that KMALLOC_MAX_SIZE will fit into MAX_ORDER
  ARM: 8632/1: ftrace: fix syscall name matching
  virtio_blk: fix panic in initialization error path
  nbd: blk_mq_init_queue returns an error code on failure, not NULL
  iw_cxgb4: do not send RX_DATA_ACK CPLs after close/abort
  ARM: dts: sunxi: Change node name for pwrseq pin on Olinuxino-lime2-emmc
  ARM: dts: sun8i: Support DTB build for NanoPi M1
  drm/virtio: fix framebuffer sparse warning
  scsi: qla2xxx: Get mutex lock before checking optrom_state
  clk/samsung: exynos542x: mark some clocks as critical
  ipv4: make tcp_notsent_lowat sysctl knob behave as true unsigned int
  phy state machine: failsafe leave invalid RUNNING state
  netfilter: use fwmark_reflect in nf_send_reset
  ASoC: rt5645: set sel_i2s_pre_div1 to 2
  spi: spi-axi: Free resources on error path
  x86/boot: Add missing declaration of string functions
  tg3: Fix race condition in tg3_get_stats64().
  net: phy: dp83867: fix irq generation
  sh_eth: R8A7740 supports packet shecksumming
  sh_eth: fix EESIPR values for SH77{34|63}
  wext: handle NULL extra data in iwe_stream_add_point better
  sparc64: Fix exception handling in UltraSPARC-III memcpy.
  sparc64: Measure receiver forward progress to avoid send mondo timeout
  xen-netback: correctly schedule rate-limited queues
  net: phy: Correctly process PHY_HALTED in phy_stop_machine()
  net/mlx5e: Schedule overflow check work to mlx5e workqueue
  net/mlx5e: Fix wrong delay calculation for overflow check scheduling
  net/mlx5e: Fix outer_header_zero() check size
  net/mlx5: Fix command bad flow on command entry allocation failure
  net/mlx5: Consider tx_enabled in all modes on remap
  sctp: fix the check for _sctp_walk_params and _sctp_walk_errors
  sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}()
  dccp: fix a memleak for dccp_feat_init err process
  dccp: fix a memleak that dccp_ipv4 doesn't put reqsk properly
  dccp: fix a memleak that dccp_ipv6 doesn't put reqsk properly
  net: ethernet: nb8800: Handle all 4 RGMII modes identically
  ipv6: Don't increase IPSTATS_MIB_FRAGFAILS twice in ip6_fragment()
  packet: fix use-after-free in prb_retire_rx_blk_timer_expired()
  openvswitch: fix potential out of bound access in parse_ct
  mcs7780: Fix initialization when CONFIG_VMAP_STACK is enabled
  rtnetlink: allocate more memory for dev_set_mac_address()
  ipv4: initialize fib_trie prior to register_netdev_notifier call.
  net: dsa: b53: Add missing ARL entries for BCM53125
  ipv6: avoid overflow of offset in ip6_find_1stfragopt
  net: Zero terminate ifr_name in dev_ifname().
  ipv4: ipv6: initialize treq->txhash in cookie_v[46]_check()
  tcp_bbr: init pacing rate on first RTT sample
  tcp_bbr: remove sk_pacing_rate=0 transient during init
  tcp_bbr: introduce bbr_init_pacing_rate_from_rtt() helper
  tcp_bbr: introduce bbr_bw_to_pacing_rate() helper
  tcp_bbr: cut pacing rate only if filled pipe
  saa7164: fix double fetch PCIe access condition
  Btrfs: fix early ENOSPC due to delalloc
  f2fs: sanity check checkpoint segno and blkoff
  media: lirc: LIRC_GET_REC_RESOLUTION should return microseconds
  mmc: core: Use device_property_read instead of of_property_read
  mmc: dw_mmc: Use device_property_read instead of of_property_read
  iscsi-target: Fix initial login PDU asynchronous socket close OOPs
  media: platform: davinci: return -EINVAL for VPFE_CMD_S_CCDC_RAW_PARAMS ioctl
  ARM: dts: tango4: Request RGMII RX and TX clock delays
  ARM: dts: armada-38x: Fix irq type for pca955
  ext4: fix overflow caused by missing cast in ext4_resize_fs()
  ext4: fix SEEK_HOLE/SEEK_DATA for blocksize < pagesize
  gpiolib: skip unwanted events, don't convert them to opposite edge
  iommu/amd: Enable ga_log_intr when enabling guest_mode
  powerpc/64: Fix __check_irq_replay missing decrementer interrupt
  powerpc/tm: Fix saving of TM SPRs in core dump
  timers: Fix overflow in get_next_timer_interrupt
  mm/page_alloc: Remove kernel address exposure in free_reserved_area()
  KVM: async_pf: make rcu irq exit if not triggered from idle task
  ASoC: do not close shared backend dailink
  drm/amdgpu: Fix undue fallthroughs in golden registers initialization
  ALSA: hda - Fix speaker output from VAIO VPCL14M1R
  cpuset: fix a deadlock due to incomplete patching of cpusets_enabled()
  mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries
  mmc: core: Fix access to HS400-ES devices
  device property: Make dev_fwnode() public
  mmc: sdhci-of-at91: force card detect value for non removable devices
  NFSv4: Fix EXCHANGE_ID corrupt verifier issue
  brcmfmac: fix memleak due to calling brcmf_sdiod_sgtable_alloc() twice
  iwlwifi: dvm: prevent an out of bounds access
  workqueue: restore WQ_UNBOUND/max_active==1 to be ordered
  libata: array underflow in ata_find_dev()
  cgroup: fix error return value from cgroup_subtree_control()
  cgroup: create dfl_root files on subsys registration
  parisc: Handle vma's whose context is not current in flush_cache_range
  ANDROID: binder: don't queue async transactions to thread.
  ANDROID: binder: don't enqueue death notifications to thread todo.
  ANDROID: binder: call poll_wait() unconditionally.
  ANDROID: keychord: Fix for a memory leak in keychord.
  ANDROID: keychord: Fix races in keychord_write.
  android: configs: move quota-related configs to recommended
  ANDROID: sdcardfs: override credential for ioctl to lower fs
  ANDROID: xt_qtaguid: handle properly request sockets

Conflicts:
	drivers/staging/android/fiq_debugger/fiq_debugger.c
	include/linux/sched.h
	kernel/locking/spinlock_debug.c
	sound/soc/soc-pcm.c

Change-Id: I163a8c98f1737eeb01b9c8a0636a91d552ef349f
Signed-off-by: Kyle Yan <kyan@codeaurora.org>

Kyle Yan   commited 2017-09-07 14:32:09 -07:00
7d337cc7f9
workqueue: implicit ordered attribute should be overridable
commit 0a94efb5acbb6980d7c9ab604372d93cd507e4d8 upstream.

5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be
ordered") automatically enabled ordered attribute for unbound
workqueues w/ max_active == 1.  Because ordered workqueues reject
max_active and some attribute changes, this implicit ordered mode
broke cases where the user creates an unbound workqueue w/ max_active
== 1 and later explicitly changes the related attributes.

This patch distinguishes explicit and implicit ordered setting and
overrides from attribute changes if implict.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
Cc: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tejun Heo   authored and   Greg Kroah-Hartman   commited 2017-08-11 08:49:37 -07:00
f9636c9bdd
workqueue: restore WQ_UNBOUND/max_active==1 to be ordered
commit 5c0338c68706be53b3dc472e4308961c36e4ece1 upstream.

The combination of WQ_UNBOUND and max_active == 1 used to imply
ordered execution.  After NUMA affinity 4c16bd327c ("workqueue:
implement NUMA affinity for unbound workqueues"), this is no longer
true due to per-node worker pools.

While the right way to create an ordered workqueue is
alloc_ordered_workqueue(), the documentation has been misleading for a
long time and people do use WQ_UNBOUND and max_active == 1 for ordered
workqueues which can lead to subtle bugs which are very difficult to
trigger.

It's unlikely that we'd see noticeable performance impact by enforcing
ordering on WQ_UNBOUND / max_active == 1 workqueues.  Let's
automatically set __WQ_ORDERED for those workqueues.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Christoph Hellwig <hch@infradead.org>
Reported-by: Alexei Potashnik <alexei@purestorage.com>
Fixes: 4c16bd327c ("workqueue: implement NUMA affinity for unbound workqueues")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tejun Heo   authored and   Greg Kroah-Hartman   commited 2017-08-11 08:49:28 -07:00
61a0adbfaa
time: Remove CONFIG_TIMER_STATS
Currently CONFIG_TIMER_STATS exposes process information across namespaces:

kernel/time/timer_list.c print_timer():

        SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);

/proc/timer_list:

 #11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570

Given that the tracer can give the same information, this patch entirely
removes CONFIG_TIMER_STATS.

Change-Id: I66e06ae2d6e32c309824310d3d9bf54d1047eab1
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Xing Gao <xgao01@email.wm.edu>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jessica Frazelle <me@jessfraz.com>
Cc: kernel-hardening@lists.openwall.com
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: http://lkml.kernel.org/r/20170208192659.GA32582@beast
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Git-commit: dfb4357da6ddbdf57d583ba64361c9d792b0e0b1
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[ohaugan@codeaurora.org: Fixed merge conflicts]
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>

Kees Cook   authored and   Olav Haugan   commited 2017-05-11 13:26:42 -07:00
a967be8dec
kernel/lib: add additional debug capabilities for data corruption
Data corruptions in the kernel often end up in system crashes that
are easier to debug closer to the time of detection. Specifically,
if we do not panic immediately after lock or list corruptions have been
detected, the problem context is lost in the ensuing system mayhem.
Add support for allowing system crash immediately after such corruptions
are detected. The CONFIG option controls the enabling/disabling of the
feature.

Change-Id: I9b2eb62da506a13007acff63e85e9515145909ff
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>

Syed Rameez Mustafa   authored and   Patrick Daly   commited 2017-03-29 13:02:14 -07:00
cf9c1e45e7
workqueue: fix possible livelock with concurrent mod_delayed_work()
When mod_delayed_work() is concurrently executed, there a potential
live lock scenario due to pool->lock contention.

Lets say both CPU#0 and CPU#4 calls mod_delayed_work() on the same
work item with 0 delay on a bounded workqueue. This workitem has
run on CPU#4 previously. CPU#0 wins the work item PENDING bit race
and proceeds to queueing. As this work has previously run on CPU#4,
it tries to acquire the corresponding pool->lock to check if it is
still running there. In the meantime, CPU#4 loops in
try_to_grab_pending() for the workitem to be linked with a pwq so
that it can steal it from pwq->pool->worklist. The CPU#4 essentially
acquires and releases the pool->lock in a busy loop and CPU#0 may
never gets this lock.

----------------                        --------------------
    CPU#0                                          CPU#4
---------------                         --------------------

blk_run_queue_async()

mod_delayed_work_on()                  queue_unplugged()

--> try_to_grab_pending() returns      blk_run_queue_async()
0 indicating PENDING bit is set
now.

__queue_delayed_work()                 mod_delayed_work_on()

__queue_work()                         try_to_grab_pending()

                                       {

--> waiting for the CPU#4's               acquire pool->lock()
pool->lock                                release pool->lock()

                                       }

Change-Id: I9aeab111f55a19478a9d045c8e3576bce3b7a7c5
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>

Pavankumar Kondeti   authored and   Channagoud Kadabi   commited 2017-02-21 10:32:46 -08:00
0c0b76489e
kthread: rename probe_kthread_data() to kthread_probe_data()
Patch series "kthread: Kthread worker API improvements"

The intention of this patchset is to make it easier to manipulate and
maintain kthreads.  Especially, I want to replace all the custom main
cycles with a generic one.  Also I want to make the kthreads sleep in a
consistent state in a common place when there is no work.

This patch (of 11):

A good practice is to prefix the names of functions by the name of the
subsystem.

This patch fixes the name of probe_kthread_data().  The other wrong
functions names are part of the kthread worker API and will be fixed
separately.

Link: http://lkml.kernel.org/r/1470754545-17632-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Petr Mladek   authored and   Linus Torvalds   commited 2016-10-11 15:06:33 -07:00
e700591ae0
workqueue: add cancel_work()
Like cancel_delayed_work(), but for regular work.

Signed-off-by: Jens Axboe <axboe@fb.com>
Mehed-by: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>

Jens Axboe   commited 2016-08-29 08:13:21 -06:00
f72b8792d1
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull smp hotplug updates from Thomas Gleixner:
 "This is the next part of the hotplug rework.

   - Convert all notifiers with a priority assigned

   - Convert all CPU_STARTING/DYING notifiers

     The final removal of the STARTING/DYING infrastructure will happen
     when the merge window closes.

  Another 700 hundred line of unpenetrable maze gone :)"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  timers/core: Correct callback order during CPU hot plug
  leds/trigger/cpu: Move from CPU_STARTING to ONLINE level
  powerpc/numa: Convert to hotplug state machine
  arm/perf: Fix hotplug state machine conversion
  irqchip/armada: Avoid unused function warnings
  ARC/time: Convert to hotplug state machine
  clocksource/atlas7: Convert to hotplug state machine
  clocksource/armada-370-xp: Convert to hotplug state machine
  clocksource/exynos_mct: Convert to hotplug state machine
  clocksource/arm_global_timer: Convert to hotplug state machine
  rcu: Convert rcutree to hotplug state machine
  KVM/arm/arm64/vgic-new: Convert to hotplug state machine
  smp/cfd: Convert core to hotplug state machine
  x86/x2apic: Convert to CPU hotplug state machine
  profile: Convert to hotplug state machine
  timers/core: Convert to hotplug state machine
  hrtimer: Convert to hotplug state machine
  x86/tboot: Convert to hotplug state machine
  arm64/armv8 deprecated: Convert to hotplug state machine
  hwtracing/coresight-etm4x: Convert to hotplug state machine
  ...

Linus Torvalds   commited 2016-07-29 13:55:30 -07:00
a6408f6cb6
Merge branches 'pm-sleep' and 'pm-tools'
* pm-sleep:
  PM / hibernate: Introduce test_resume mode for hibernation
  x86 / hibernate: Use hlt_play_dead() when resuming from hibernation
  PM / hibernate: Image data protection during restoration
  PM / hibernate: Add missing braces in __register_nosave_region()
  PM / hibernate: Clean up comments in snapshot.c
  PM / hibernate: Clean up function headers in snapshot.c
  PM / hibernate: Add missing braces in hibernate_setup()
  PM / hibernate: Recycle safe pages after image restoration
  PM / hibernate: Simplify mark_unsafe_pages()
  PM / hibernate: Do not free preallocated safe pages during image restore
  PM / suspend: show workqueue state in suspend flow
  PM / sleep: make PM notifiers called symmetrically
  PM / sleep: Make pm_prepare_console() return void
  PM / Hibernate: Don't let kasan instrument snapshot.c

* pm-tools:
  PM / tools: scripts: AnalyzeSuspend v4.2
  tools/turbostat: allow user to alter DESTDIR and PREFIX

Rafael J. Wysocki   commited 2016-07-25 13:44:32 +02:00
7f234a4d8a
workqueue: Convert to state machine callbacks
Get rid of the prio ordering of the separate notifiers and use a proper state
callback pair.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153335.197083890@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Thomas Gleixner   authored and   Ingo Molnar   commited 2016-07-14 09:34:43 +02:00
7ee681b252
PM / suspend: show workqueue state in suspend flow
If freezable workqueue aborts suspend flow, show
workqueue state for debug purpose.

Signed-off-by: Roger Lu <roger.lu@mediatek.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Roger Lu   authored and   Rafael J. Wysocki   commited 2016-07-02 01:42:48 +02:00
7b776af66d
workqueue: Fix setting affinity of unbound worker threads
With commit e9d867a67f ("sched: Allow per-cpu kernel threads to
run on online && !active"), __set_cpus_allowed_ptr() expects that only
strict per-cpu kernel threads can have affinity to an online CPU which
is not yet active.

This assumption is currently broken in the CPU_ONLINE notification
handler for the workqueues where restore_unbound_workers_cpumask()
calls set_cpus_allowed_ptr() when the first cpu in the unbound
worker's pool->attr->cpumask comes online. Since
set_cpus_allowed_ptr() is called with pool->attr->cpumask in which
only one CPU is online which is not yet active, we get the following
WARN_ON during an CPU online operation.

------------[ cut here ]------------
WARNING: CPU: 40 PID: 248 at kernel/sched/core.c:1166
__set_cpus_allowed_ptr+0x228/0x2e0
Modules linked in:
CPU: 40 PID: 248 Comm: cpuhp/40 Not tainted 4.6.0-autotest+ #4
<..snip..>
Call Trace:
[c000000f273ff920] [c00000000010493c] __set_cpus_allowed_ptr+0x2cc/0x2e0 (unreliable)
[c000000f273ffac0] [c0000000000ed4b0] workqueue_cpu_up_callback+0x2c0/0x470
[c000000f273ffb70] [c0000000000f5c58] notifier_call_chain+0x98/0x100
[c000000f273ffbc0] [c0000000000c5ed0] __cpu_notify+0x70/0xe0
[c000000f273ffc00] [c0000000000c6028] notify_online+0x38/0x50
[c000000f273ffc30] [c0000000000c5214] cpuhp_invoke_callback+0x84/0x250
[c000000f273ffc90] [c0000000000c562c] cpuhp_up_callbacks+0x5c/0x120
[c000000f273ffce0] [c0000000000c64d4] cpuhp_thread_fun+0x184/0x1c0
[c000000f273ffd20] [c0000000000fa050] smpboot_thread_fn+0x290/0x2a0
[c000000f273ffd80] [c0000000000f45b0] kthread+0x110/0x130
[c000000f273ffe30] [c000000000009570] ret_from_kernel_thread+0x5c/0x6c
---[ end trace 00f1456578b2a3b2 ]---

This patch fixes this by limiting the mask to the intersection of
the pool affinity and online CPUs.

Changelog-cribbed-from: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

Peter Zijlstra   authored and   Tejun Heo   commited 2016-06-16 15:37:05 -04:00
d945b5e9f0
debugobjects: insulate non-fixup logic related to static obj from fixup callbacks
When activating a static object we need make sure that the object is
tracked in the object tracker.  If it is a non-static object then the
activation is illegal.

In previous implementation, each subsystem need take care of this in
their fixup callbacks.  Actually we can put it into debugobjects core.
Thus we can save duplicated code, and have *pure* fixup callbacks.

To achieve this, a new callback "is_static_object" is introduced to let
the type specific code decide whether a object is static or not.  If
yes, we take it into object tracker, otherwise give warning and invoke
fixup callback.

This change has paassed debugobjects selftest, and I also do some test
with all debugobjects supports enabled.

At last, I have a concern about the fixups that can it change the object
which is in incorrect state on fixup? Because the 'addr' may not point
to any valid object if a non-static object is not tracked.  Then Change
such object can overwrite someone's memory and cause unexpected
behaviour.  For example, the timer_fixup_activate bind timer to function
stub_timer.

Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com
[changbin.du@intel.com: improve code comments where invoke the new is_static_object callback]
  Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.com
Signed-off-by: Du, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Du, Changbin   authored and   Linus Torvalds   commited 2016-05-19 19:12:14 -07:00
b9fdac7f66
workqueue: update debugobjects fixup callbacks return type
Update the return type to use bool instead of int, corresponding to
change (debugobjects: make fixup functions return bool instead of int)

Signed-off-by: Du, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Du, Changbin   authored and   Linus Torvalds   commited 2016-05-19 19:12:14 -07:00
02a982a6ec
Merge branch 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
 "CPU hotplug callbacks can invoke DOWN_FAILED w/o preceding
  DOWN_PREPARE which can trigger a WARN_ON() in workqueue.

  The bug has been there for a very long time.  It only triggers if CPU
  down fails at a specific point and I don't think it has adverse
  effects other than the warning messages.  The fix is very low impact"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix rebind bound workers warning

Linus Torvalds   commited 2016-05-13 16:16:51 -07:00
da92223908
workqueue: fix rebind bound workers warning
------------[ cut here ]------------
WARNING: CPU: 0 PID: 16 at kernel/workqueue.c:4559 rebind_workers+0x1c0/0x1d0
Modules linked in:
CPU: 0 PID: 16 Comm: cpuhp/0 Not tainted 4.6.0-rc4+ #31
Hardware name: IBM IBM System x3550 M4 Server -[7914IUW]-/00Y8603, BIOS -[D7E128FUS-1.40]- 07/23/2013
 0000000000000000 ffff881037babb58 ffffffff8139d885 0000000000000010
 0000000000000000 0000000000000000 0000000000000000 ffff881037babba8
 ffffffff8108505d ffff881037ba0000 000011cf3e7d6e60 0000000000000046
Call Trace:
 dump_stack+0x89/0xd4
 __warn+0xfd/0x120
 warn_slowpath_null+0x1d/0x20
 rebind_workers+0x1c0/0x1d0
 workqueue_cpu_up_callback+0xf5/0x1d0
 notifier_call_chain+0x64/0x90
 ? trace_hardirqs_on_caller+0xf2/0x220
 ? notify_prepare+0x80/0x80
 __raw_notifier_call_chain+0xe/0x10
 __cpu_notify+0x35/0x50
 notify_down_prepare+0x5e/0x80
 ? notify_prepare+0x80/0x80
 cpuhp_invoke_callback+0x73/0x330
 ? __schedule+0x33e/0x8a0
 cpuhp_down_callbacks+0x51/0xc0
 cpuhp_thread_fun+0xc1/0xf0
 smpboot_thread_fn+0x159/0x2a0
 ? smpboot_create_threads+0x80/0x80
 kthread+0xef/0x110
 ? wait_for_completion+0xf0/0x120
 ? schedule_tail+0x35/0xf0
 ret_from_fork+0x22/0x50
 ? __init_kthread_worker+0x70/0x70
---[ end trace eb12ae47d2382d8f ]---
notify_down_prepare: attempt to take down CPU 0 failed

This bug can be reproduced by below config w/ nohz_full= all cpus:

CONFIG_BOOTPARAM_HOTPLUG_CPU0=y
CONFIG_DEBUG_HOTPLUG_CPU0=y
CONFIG_NO_HZ_FULL=y

As Thomas pointed out:

| If a down prepare callback fails, then DOWN_FAILED is invoked for all
| callbacks which have successfully executed DOWN_PREPARE.
|
| But, workqueue has actually two notifiers. One which handles
| UP/DOWN_FAILED/ONLINE and one which handles DOWN_PREPARE.
|
| Now look at the priorities of those callbacks:
|
| CPU_PRI_WORKQUEUE_UP        = 5
| CPU_PRI_WORKQUEUE_DOWN      = -5
|
| So the call order on DOWN_PREPARE is:
|
| CB 1
| CB ...
| CB workqueue_up() -> Ignores DOWN_PREPARE
| CB ...
| CB X ---> Fails
|
| So we call up to CB X with DOWN_FAILED
|
| CB 1
| CB ...
| CB workqueue_up() -> Handles DOWN_FAILED
| CB ...
| CB X-1
|
| So the problem is that the workqueue stuff handles DOWN_FAILED in the up
| callback, while it should do it in the down callback. Which is not a good idea
| either because it wants to be called early on rollback...
|
| Brilliant stuff, isn't it? The hotplug rework will solve this problem because
| the callbacks become symetric, but for the existing mess, we need some
| workaround in the workqueue code.

The boot CPU handles housekeeping duty(unbound timers, workqueues,
timekeeping, ...) on behalf of full dynticks CPUs. It must remain
online when nohz full is enabled. There is a priority set to every
notifier_blocks:

workqueue_cpu_up > tick_nohz_cpu_down > workqueue_cpu_down

So tick_nohz_cpu_down callback failed when down prepare cpu 0, and
notifier_blocks behind tick_nohz_cpu_down will not be called any
more, which leads to workers are actually not unbound. Then hotplug
state machine will fallback to undo and online cpu 0 again. Workers
will be rebound unconditionally even if they are not unbound and
trigger the warning in this progress.

This patch fix it by catching !DISASSOCIATED to avoid rebind bound
workers.

Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
Suggested-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>

Wanpeng Li   authored and   Tejun Heo   commited 2016-05-12 12:00:23 -04:00
f7c17d26f4
Merge branch 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
 "So, it turns out we had a silly bug in the most fundamental part of
  workqueue for a very long time.  AFAICS, this dates back to pre-git
  era and has quite likely been there from the time workqueue was first
  introduced.

  A work item uses its PENDING bit to synchronize multiple queuers.
  Anyone who wins the PENDING bit owns the pending state of the work
  item.  Whether a queuer wins or loses the race, one thing should be
  guaranteed - there will soon be at least one execution of the work
  item - where "after" means that the execution instance would be able
  to see all the changes that the queuer has made prior to the queueing
  attempt.

  Unfortunately, we were missing a smp_mb() after clearing PENDING for
  execution, so nothing guaranteed visibility of the changes that a
  queueing loser has made, which manifested as a reproducible blk-mq
  stall.

  Lots of kudos to Roman for debugging the problem.  The patch for
  -stable is the minimal one.  For v3.7, Peter is working on a patch to
  make the code path slightly more efficient and less fragile"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix ghost PENDING flag while doing MQ IO

Linus Torvalds   commited 2016-04-27 12:03:59 -07:00
b75a2bf899
workqueue: fix ghost PENDING flag while doing MQ IO
The bug in a workqueue leads to a stalled IO request in MQ ctx->rq_list
with the following backtrace:

[  601.347452] INFO: task kworker/u129:5:1636 blocked for more than 120 seconds.
[  601.347574]       Tainted: G           O    4.4.5-1-storage+ #6
[  601.347651] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  601.348142] kworker/u129:5  D ffff880803077988     0  1636      2 0x00000000
[  601.348519] Workqueue: ibnbd_server_fileio_wq ibnbd_dev_file_submit_io_worker [ibnbd_server]
[  601.348999]  ffff880803077988 ffff88080466b900 ffff8808033f9c80 ffff880803078000
[  601.349662]  ffff880807c95000 7fffffffffffffff ffffffff815b0920 ffff880803077ad0
[  601.350333]  ffff8808030779a0 ffffffff815b01d5 0000000000000000 ffff880803077a38
[  601.350965] Call Trace:
[  601.351203]  [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[  601.351444]  [<ffffffff815b01d5>] schedule+0x35/0x80
[  601.351709]  [<ffffffff815b2dd2>] schedule_timeout+0x192/0x230
[  601.351958]  [<ffffffff812d43f7>] ? blk_flush_plug_list+0xc7/0x220
[  601.352208]  [<ffffffff810bd737>] ? ktime_get+0x37/0xa0
[  601.352446]  [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[  601.352688]  [<ffffffff815af784>] io_schedule_timeout+0xa4/0x110
[  601.352951]  [<ffffffff815b3a4e>] ? _raw_spin_unlock_irqrestore+0xe/0x10
[  601.353196]  [<ffffffff815b093b>] bit_wait_io+0x1b/0x70
[  601.353440]  [<ffffffff815b056d>] __wait_on_bit+0x5d/0x90
[  601.353689]  [<ffffffff81127bd0>] wait_on_page_bit+0xc0/0xd0
[  601.353958]  [<ffffffff81096db0>] ? autoremove_wake_function+0x40/0x40
[  601.354200]  [<ffffffff81127cc4>] __filemap_fdatawait_range+0xe4/0x140
[  601.354441]  [<ffffffff81127d34>] filemap_fdatawait_range+0x14/0x30
[  601.354688]  [<ffffffff81129a9f>] filemap_write_and_wait_range+0x3f/0x70
[  601.354932]  [<ffffffff811ced3b>] blkdev_fsync+0x1b/0x50
[  601.355193]  [<ffffffff811c82d9>] vfs_fsync_range+0x49/0xa0
[  601.355432]  [<ffffffff811cf45a>] blkdev_write_iter+0xca/0x100
[  601.355679]  [<ffffffff81197b1a>] __vfs_write+0xaa/0xe0
[  601.355925]  [<ffffffff81198379>] vfs_write+0xa9/0x1a0
[  601.356164]  [<ffffffff811c59d8>] kernel_write+0x38/0x50

The underlying device is a null_blk, with default parameters:

  queue_mode    = MQ
  submit_queues = 1

Verification that nullb0 has something inflight:

root@pserver8:~# cat /sys/block/nullb0/inflight
       0        1
root@pserver8:~# find /sys/block/nullb0/mq/0/cpu* -name rq_list -print -exec cat {} \;
...
/sys/block/nullb0/mq/0/cpu2/rq_list
CTX pending:
        ffff8838038e2400
...

During debug it became clear that stalled request is always inserted in
the rq_list from the following path:

   save_stack_trace_tsk + 34
   blk_mq_insert_requests + 231
   blk_mq_flush_plug_list + 281
   blk_flush_plug_list + 199
   wait_on_page_bit + 192
   __filemap_fdatawait_range + 228
   filemap_fdatawait_range + 20
   filemap_write_and_wait_range + 63
   blkdev_fsync + 27
   vfs_fsync_range + 73
   blkdev_write_iter + 202
   __vfs_write + 170
   vfs_write + 169
   kernel_write + 56

So blk_flush_plug_list() was called with from_schedule == true.

If from_schedule is true, that means that finally blk_mq_insert_requests()
offloads execution of __blk_mq_run_hw_queue() and uses kblockd workqueue,
i.e. it calls kblockd_schedule_delayed_work_on().

That means, that we race with another CPU, which is about to execute
__blk_mq_run_hw_queue() work.

Further debugging shows the following traces from different CPUs:

  CPU#0                                  CPU#1
  ----------------------------------     -------------------------------
  reqeust A inserted
  STORE hctx->ctx_map[0] bit marked
  kblockd_schedule...() returns 1
  <schedule to kblockd workqueue>
                                         request B inserted
                                         STORE hctx->ctx_map[1] bit marked
                                         kblockd_schedule...() returns 0
  *** WORK PENDING bit is cleared ***
  flush_busy_ctxs() is executed, but
  bit 1, set by CPU#1, is not observed

As a result request B pended forever.

This behaviour can be explained by speculative LOAD of hctx->ctx_map on
CPU#0, which is reordered with clear of PENDING bit and executed _before_
actual STORE of bit 1 on CPU#1.

The proper fix is an explicit full barrier <mfence>, which guarantees
that clear of PENDING bit is to be executed before all possible
speculative LOADS or STORES inside actual work function.

Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Michael Wang <yun.wang@profitbricks.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>

Roman Pen   authored and   Tejun Heo   commited 2016-04-26 11:23:22 -04:00
346c09f804
Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo:
 "Three trivial workqueue changes"

* 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Fix comment for work_on_cpu()
  sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
  workqueue: Replace usage of init_name with dev_set_name()

Linus Torvalds   commited 2016-03-18 20:05:39 -07:00
ef504fa591
tags: Fix DEFINE_PER_CPU expansions
$ make tags
  GEN     tags
ctags: Warning: drivers/acpi/processor_idle.c:64: null expansion of name pattern "\1"
ctags: Warning: drivers/xen/events/events_2l.c:41: null expansion of name pattern "\1"
ctags: Warning: kernel/locking/lockdep.c:151: null expansion of name pattern "\1"
ctags: Warning: kernel/rcu/rcutorture.c:133: null expansion of name pattern "\1"
ctags: Warning: kernel/rcu/rcutorture.c:135: null expansion of name pattern "\1"
ctags: Warning: kernel/workqueue.c:323: null expansion of name pattern "\1"
ctags: Warning: net/ipv4/syncookies.c:53: null expansion of name pattern "\1"
ctags: Warning: net/ipv6/syncookies.c:44: null expansion of name pattern "\1"
ctags: Warning: net/rds/page.c:45: null expansion of name pattern "\1"

Which are all the result of the DEFINE_PER_CPU pattern:

  scripts/tags.sh:200:	'/\<DEFINE_PER_CPU([^,]*, *\([[:alnum:]_]*\)/\1/v/'
  scripts/tags.sh:201:	'/\<DEFINE_PER_CPU_SHARED_ALIGNED([^,]*, *\([[:alnum:]_]*\)/\1/v/'

The below cures them. All except the workqueue one are within reasonable
distance of the 80 char limit. TJ do you have any preference on how to
fix the wq one, or shall we just not care its too long?

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Peter Zijlstra   authored and   Linus Torvalds   commited 2016-03-15 16:55:16 -07:00
25528213fe
workqueue: Fix comment for work_on_cpu()
Function is processed in thread context, not in user context.

Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

Anna-Maria Gleixner   authored and   Tejun Heo   commited 2016-03-11 12:39:01 -05:00
22aceb3176
sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
Given that wq_worker_sleeping() could only be called for a
CPU it is running on, we do not need passing a CPU ID as an
argument.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Alexander Gordeev   authored and   Tejun Heo   commited 2016-03-02 10:28:47 -05:00
9b7f6597f0
workqueue: Replace usage of init_name with dev_set_name()
The init_name property of the device struct is sort of a hack and should
only be used for statically allocated devices. Since the device is
dynamically allocated here it is safe to use the proper way to set a
devices name by calling dev_set_name().

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

Lars-Peter Clausen   authored and   Tejun Heo   commited 2016-02-17 16:14:18 -05:00
23217b443b
workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup
When looking up the pool_workqueue to use for an unbound workqueue,
workqueue assumes that the target CPU is always bound to a valid NUMA
node.  However, currently, when a CPU goes offline, the mapping is
destroyed and cpu_to_node() returns NUMA_NO_NODE.

This has always been broken but hasn't triggered often enough before
874bbfe600 ("workqueue: make sure delayed work run in local cpu").
After the commit, workqueue forcifully assigns the local CPU for
delayed work items without explicit target CPU to fix a different
issue.  This widens the window where CPU can go offline while a
delayed work item is pending causing delayed work items dispatched
with target CPU set to an already offlined CPU.  The resulting
NUMA_NO_NODE mapping makes workqueue try to queue the work item on a
NULL pool_workqueue and thus crash.

While 874bbfe600 has been reverted for a different reason making the
bug less visible again, it can still happen.  Fix it by mapping
NUMA_NO_NODE to the default pool_workqueue from unbound_pwq_by_node().
This is a temporary workaround.  The long term solution is keeping CPU
-> NODE mapping stable across CPU off/online cycles which is being
worked on.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/g/1454424264.11183.46.camel@gmail.com
Link: http://lkml.kernel.org/g/1453702100-2597-1-git-send-email-tangchen@cn.fujitsu.com

Tejun Heo   commited 2016-02-10 12:13:05 -05:00
d6e022f1d2
workqueue: implement "workqueue.debug_force_rr_cpu" debug feature
Workqueue used to guarantee local execution for work items queued
without explicit target CPU.  The guarantee is gone now which can
break some usages in subtle ways.  To flush out those cases, this
patch implements a debug feature which forces round-robin CPU
selection for all such work items.

The debug feature defaults to off and can be enabled with a kernel
parameter.  The default can be flipped with a debug config option.

If you hit this commit during bisection, please refer to 041bd12e27
("Revert "workqueue: make sure delayed work run in local cpu"") for
more information and ping me.

Signed-off-by: Tejun Heo <tj@kernel.org>

Tejun Heo   commited 2016-02-09 17:59:38 -05:00
f303fccb82
workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs
WORK_CPU_UNBOUND work items queued to a bound workqueue always run
locally.  This is a good thing normally, but not when the user has
asked us to keep unbound work away from certain CPUs.  Round robin
these to wq_unbound_cpumask CPUs instead, as perturbation avoidance
trumps performance.

tj: Cosmetic and comment changes.  WARN_ON_ONCE() dropped from empty
    (wq_unbound_cpumask AND cpu_online_mask).  If we want that, it
    should be done when config changes.

Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Mike Galbraith   authored and   Tejun Heo   commited 2016-02-09 17:59:38 -05:00
ef55718044
Revert "workqueue: make sure delayed work run in local cpu"
This reverts commit 874bbfe600.

Workqueue used to implicity guarantee that work items queued without
explicit CPU specified are put on the local CPU.  Recent changes in
timer broke the guarantee and led to vmstat breakage which was fixed
by 176bed1de5 ("vmstat: explicitly schedule per-cpu work on the CPU
we need it to run on").

vmstat is the most likely to expose the issue and it's quite possible
that there are other similar problems which are a lot more difficult
to trigger.  As a preventive measure, 874bbfe600 ("workqueue: make
sure delayed work run in local cpu") was applied to restore the local
CPU guarnatee.  Unfortunately, the change exposed a bug in timer code
which got fixed by 22b886dd10 ("timers: Use proper base migration in
add_timer_on()").  Due to code restructuring, the commit couldn't be
backported beyond certain point and stable kernels which only had
874bbfe600 started crashing.

The local CPU guarantee was accidental more than anything else and we
want to get rid of it anyway.  As, with the vmstat case fixed,
874bbfe600 is causing more problems than it's fixing, it has been
decided to take the chance and officially break the guarantee by
reverting the commit.  A debug feature will be added to force foreign
CPU assignment to expose cases relying on the guarantee and fixes for
the individual cases will be backported to stable as necessary.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 874bbfe600 ("workqueue: make sure delayed work run in local cpu")
Link: http://lkml.kernel.org/g/20160120211926.GJ10810@quack.suse.cz
Cc: stable@vger.kernel.org
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Daniel Bilik <daniel.bilik@neosystem.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Shaohua Li <shli@fb.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Bilik <daniel.bilik@neosystem.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>

Tejun Heo   commited 2016-02-09 16:11:26 -05:00
041bd12e27
workqueue: skip flush dependency checks for legacy workqueues
fca839c00a ("workqueue: warn if memory reclaim tries to flush
!WQ_MEM_RECLAIM workqueue") implemented flush dependency warning which
triggers if a PF_MEMALLOC task or WQ_MEM_RECLAIM workqueue tries to
flush a !WQ_MEM_RECLAIM workquee.

This assumes that workqueues marked with WQ_MEM_RECLAIM sit in memory
reclaim path and making it depend on something which may need more
memory to make forward progress can lead to deadlocks.  Unfortunately,
workqueues created with the legacy create*_workqueue() interface
always have WQ_MEM_RECLAIM regardless of whether they are depended
upon memory reclaim or not.  These spurious WQ_MEM_RECLAIM markings
cause spurious triggering of the flush dependency checks.

  WARNING: CPU: 0 PID: 6 at kernel/workqueue.c:2361 check_flush_dependency+0x138/0x144()
  workqueue: WQ_MEM_RECLAIM deferwq:deferred_probe_work_func is flushing !WQ_MEM_RECLAIM events:lru_add_drain_per_cpu
  ...
  Workqueue: deferwq deferred_probe_work_func
  [<c0017acc>] (unwind_backtrace) from [<c0013134>] (show_stack+0x10/0x14)
  [<c0013134>] (show_stack) from [<c0245f18>] (dump_stack+0x94/0xd4)
  [<c0245f18>] (dump_stack) from [<c0026f9c>] (warn_slowpath_common+0x80/0xb0)
  [<c0026f9c>] (warn_slowpath_common) from [<c0026ffc>] (warn_slowpath_fmt+0x30/0x40)
  [<c0026ffc>] (warn_slowpath_fmt) from [<c00390b8>] (check_flush_dependency+0x138/0x144)
  [<c00390b8>] (check_flush_dependency) from [<c0039ca0>] (flush_work+0x50/0x15c)
  [<c0039ca0>] (flush_work) from [<c00c51b0>] (lru_add_drain_all+0x130/0x180)
  [<c00c51b0>] (lru_add_drain_all) from [<c00f728c>] (migrate_prep+0x8/0x10)
  [<c00f728c>] (migrate_prep) from [<c00bfbc4>] (alloc_contig_range+0xd8/0x338)
  [<c00bfbc4>] (alloc_contig_range) from [<c00f8f18>] (cma_alloc+0xe0/0x1ac)
  [<c00f8f18>] (cma_alloc) from [<c001cac4>] (__alloc_from_contiguous+0x38/0xd8)
  [<c001cac4>] (__alloc_from_contiguous) from [<c001ceb4>] (__dma_alloc+0x240/0x278)
  [<c001ceb4>] (__dma_alloc) from [<c001cf78>] (arm_dma_alloc+0x54/0x5c)
  [<c001cf78>] (arm_dma_alloc) from [<c0355ea4>] (dmam_alloc_coherent+0xc0/0xec)
  [<c0355ea4>] (dmam_alloc_coherent) from [<c039cc4c>] (ahci_port_start+0x150/0x1dc)
  [<c039cc4c>] (ahci_port_start) from [<c0384734>] (ata_host_start.part.3+0xc8/0x1c8)
  [<c0384734>] (ata_host_start.part.3) from [<c03898dc>] (ata_host_activate+0x50/0x148)
  [<c03898dc>] (ata_host_activate) from [<c039d558>] (ahci_host_activate+0x44/0x114)
  [<c039d558>] (ahci_host_activate) from [<c039f05c>] (ahci_platform_init_host+0x1d8/0x3c8)
  [<c039f05c>] (ahci_platform_init_host) from [<c039e6bc>] (tegra_ahci_probe+0x448/0x4e8)
  [<c039e6bc>] (tegra_ahci_probe) from [<c0347058>] (platform_drv_probe+0x50/0xac)
  [<c0347058>] (platform_drv_probe) from [<c03458cc>] (driver_probe_device+0x214/0x2c0)
  [<c03458cc>] (driver_probe_device) from [<c0343cc0>] (bus_for_each_drv+0x60/0x94)
  [<c0343cc0>] (bus_for_each_drv) from [<c03455d8>] (__device_attach+0xb0/0x114)
  [<c03455d8>] (__device_attach) from [<c0344ab8>] (bus_probe_device+0x84/0x8c)
  [<c0344ab8>] (bus_probe_device) from [<c0344f48>] (deferred_probe_work_func+0x68/0x98)
  [<c0344f48>] (deferred_probe_work_func) from [<c003b738>] (process_one_work+0x120/0x3f8)
  [<c003b738>] (process_one_work) from [<c003ba48>] (worker_thread+0x38/0x55c)
  [<c003ba48>] (worker_thread) from [<c0040f14>] (kthread+0xdc/0xf4)
  [<c0040f14>] (kthread) from [<c000f778>] (ret_from_fork+0x14/0x3c)

Fix it by marking workqueues created via create*_workqueue() with
__WQ_LEGACY and disabling flush dependency checks on them.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Thierry Reding <thierry.reding@gmail.com>
Link: http://lkml.kernel.org/g/20160126173843.GA11115@ulmo.nvidia.com
Fixes: fca839c00a ("workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue")

Tejun Heo   commited 2016-01-29 13:31:10 -05:00
23d11a58a9
workqueue: simplify the apply_workqueue_attrs_locked()
If the apply_wqattrs_prepare() returns NULL, it has already cleaned up
the related resources, so it can return directly and avoid calling the
clean up function again.

This doesn't introduce any functional changes.

Signed-off-by: wanghaibin <wanghaibin.wang@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

wanghaibin   authored and   Tejun Heo   commited 2016-01-07 11:04:34 -05:00
6201171e3b
workqueue: implement lockup detector
Workqueue stalls can happen from a variety of usage bugs such as
missing WQ_MEM_RECLAIM flag or concurrency managed work item
indefinitely staying RUNNING.  These stalls can be extremely difficult
to hunt down because the usual warning mechanisms can't detect
workqueue stalls and the internal state is pretty opaque.

To alleviate the situation, this patch implements workqueue lockup
detector.  It periodically monitors all worker_pools periodically and,
if any pool failed to make forward progress longer than the threshold
duration, triggers warning and dumps workqueue state as follows.

 BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 31s!
 Showing busy workqueues and worker pools:
 workqueue events: flags=0x0
   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=17/256
     pending: monkey_wrench_fn, e1000_watchdog, cache_reap, vmstat_shepherd, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, release_one_tty, cgroup_release_agent
 workqueue events_power_efficient: flags=0x80
   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
     pending: check_lifetime, neigh_periodic_work
 workqueue cgroup_pidlist_destroy: flags=0x0
   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1
     pending: cgroup_pidlist_destroy_work_fn
 ...

The detection mechanism is controller through kernel parameter
workqueue.watchdog_thresh and can be updated at runtime through the
sysfs module parameter file.

v2: Decoupled from softlockup control knobs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>

Tejun Heo   commited 2015-12-08 11:29:47 -05:00
82607adcf9
workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue
Task or work item involved in memory reclaim trying to flush a
non-WQ_MEM_RECLAIM workqueue or one of its work items can lead to
deadlock.  Trigger WARN_ONCE() if such conditions are detected.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>

Tejun Heo   commited 2015-12-08 11:29:36 -05:00
fca839c00a
Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue update from Tejun Heo:
 "This pull request contains one patch to make an unbound worker pool
  allocated from the NUMA node containing it if such node exists.  As
  unbound worker pools are node-affine by default, this makes most pools
  allocated on the right node"

* 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Allocate the unbound pool using local node memory

Linus Torvalds   commited 2015-11-05 14:16:27 -08:00
e25ac7ddaa
workqueue: Allocate the unbound pool using local node memory
Currently, get_unbound_pool() uses kzalloc() to allocate the
worker pool. Actually, we can use the right node to do the
allocation, achieving local memory access.

This patch selects target node first, and uses kzalloc_node()
instead.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

Xunlei Pang   authored and   Tejun Heo   commited 2015-10-12 12:17:31 -04:00
e2273584d3
workqueue: make sure delayed work run in local cpu
My system keeps crashing with below message. vmstat_update() schedules a delayed
work in current cpu and expects the work runs in the cpu.
schedule_delayed_work() is expected to make delayed work run in local cpu. The
problem is timer can be migrated with NO_HZ. __queue_work() queues work in
timer handler, which could run in a different cpu other than where the delayed
work is scheduled. The end result is the delayed work runs in different cpu.
The patch makes __queue_delayed_work records local cpu earlier. Where the timer
runs doesn't change where the work runs with the change.

[   28.010131] ------------[ cut here ]------------
[   28.010609] kernel BUG at ../mm/vmstat.c:1392!
[   28.011099] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
[   28.011860] Modules linked in:
[   28.012245] CPU: 0 PID: 289 Comm: kworker/0:3 Tainted: G        W4.3.0-rc3+ #634
[   28.013065] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153802- 04/01/2014
[   28.014160] Workqueue: events vmstat_update
[   28.014571] task: ffff880117682580 ti: ffff8800ba428000 task.ti: ffff8800ba428000
[   28.015445] RIP: 0010:[<ffffffff8115f921>]  [<ffffffff8115f921>]vmstat_update+0x31/0x80
[   28.016282] RSP: 0018:ffff8800ba42fd80  EFLAGS: 00010297
[   28.016812] RAX: 0000000000000000 RBX: ffff88011a858dc0 RCX:0000000000000000
[   28.017585] RDX: ffff880117682580 RSI: ffffffff81f14d8c RDI:ffffffff81f4df8d
[   28.018366] RBP: ffff8800ba42fd90 R08: 0000000000000001 R09:0000000000000000
[   28.019169] R10: 0000000000000000 R11: 0000000000000121 R12:ffff8800baa9f640
[   28.019947] R13: ffff88011a81e340 R14: ffff88011a823700 R15:0000000000000000
[   28.020071] FS:  0000000000000000(0000) GS:ffff88011a800000(0000)knlGS:0000000000000000
[   28.020071] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   28.020071] CR2: 00007ff6144b01d0 CR3: 00000000b8e93000 CR4:00000000000006f0
[   28.020071] Stack:
[   28.020071]  ffff88011a858dc0 ffff8800baa9f640 ffff8800ba42fe00ffffffff8106bd88
[   28.020071]  ffffffff8106bd0b 0000000000000096 0000000000000000ffffffff82f9b1e8
[   28.020071]  ffffffff829f0b10 0000000000000000 ffffffff81f18460ffff88011a81e340
[   28.020071] Call Trace:
[   28.020071]  [<ffffffff8106bd88>] process_one_work+0x1c8/0x540
[   28.020071]  [<ffffffff8106bd0b>] ? process_one_work+0x14b/0x540
[   28.020071]  [<ffffffff8106c214>] worker_thread+0x114/0x460
[   28.020071]  [<ffffffff8106c100>] ? process_one_work+0x540/0x540
[   28.020071]  [<ffffffff81071bf8>] kthread+0xf8/0x110
[   28.020071]  [<ffffffff81071b00>] ?kthread_create_on_node+0x200/0x200
[   28.020071]  [<ffffffff81a6522f>] ret_from_fork+0x3f/0x70
[   28.020071]  [<ffffffff81071b00>] ?kthread_create_on_node+0x200/0x200

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v2.6.31+

Shaohua Li   authored and   Tejun Heo   commited 2015-09-30 13:06:46 -04:00
874bbfe600
Merge branch 'for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo:
 "Only three trivial changes for workqueue this time - doc, MAINTAINERS
  and EXPORT_SYMBOL updates"

* 'for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix some docbook warnings
  workqueue: Make flush_workqueue() available again to non GPL modules
  workqueue: add myself as a dedicated reviwer

Linus Torvalds   commited 2015-09-02 08:02:20 -07:00
7d3e2eb178
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "The biggest change in this cycle is the rewrite of the main SMP load
  balancing metric: the CPU load/utilization.  The main goal was to make
  the metric more precise and more representative - see the changelog of
  this commit for the gory details:

    9d89c257df ("sched/fair: Rewrite runnable load and utilization average tracking")

  It is done in a way that significantly reduces complexity of the code:

    5 files changed, 249 insertions(+), 494 deletions(-)

  and the performance testing results are encouraging.  Nevertheless we
  need to keep an eye on potential regressions, since this potentially
  affects every SMP workload in existence.

  This work comes from Yuyang Du.

  Other changes:

   - SCHED_DL updates.  (Andrea Parri)

   - Simplify architecture callbacks by removing finish_arch_switch().
     (Peter Zijlstra et al)

   - cputime accounting: guarantee stime + utime == rtime.  (Peter
     Zijlstra)

   - optimize idle CPU wakeups some more - inspired by Facebook server
     loads.  (Mike Galbraith)

   - stop_machine fixes and updates.  (Oleg Nesterov)

   - Introduce the 'trace_sched_waking' tracepoint.  (Peter Zijlstra)

   - sched/numa tweaks.  (Srikar Dronamraju)

   - misc fixes and small cleanups"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
  sched/deadline: Fix comment in enqueue_task_dl()
  sched/deadline: Fix comment in push_dl_tasks()
  sched: Change the sched_class::set_cpus_allowed() calling context
  sched: Make sched_class::set_cpus_allowed() unconditional
  sched: Fix a race between __kthread_bind() and sched_setaffinity()
  sched: Ensure a task has a non-normalized vruntime when returning back to CFS
  sched/numa: Fix NUMA_DIRECT topology identification
  tile: Reorganize _switch_to()
  sched, sparc32: Update scheduler comments in copy_thread()
  sched: Remove finish_arch_switch()
  sched, tile: Remove finish_arch_switch
  sched, sh: Fold finish_arch_switch() into switch_to()
  sched, score: Remove finish_arch_switch()
  sched, avr32: Remove finish_arch_switch()
  sched, MIPS: Get rid of finish_arch_switch()
  sched, arm: Remove finish_arch_switch()
  sched/fair: Clean up load average references
  sched/fair: Provide runnable_load_avg back to cfs_rq
  sched/fair: Remove task and group entity load when they are dead
  sched/fair: Init cfs_rq's sched_entity load average
  ...

Linus Torvalds   commited 2015-08-31 20:26:22 -07:00
a1d8561172
sched: Fix a race between __kthread_bind() and sched_setaffinity()
Because sched_setscheduler() checks p->flags & PF_NO_SETAFFINITY
without locks, a caller might observe an old value and race with the
set_cpus_allowed_ptr() call from __kthread_bind() and effectively undo
it:

	__kthread_bind()
	  do_set_cpus_allowed()
						<SYSCALL>
						  sched_setaffinity()
						    if (p->flags & PF_NO_SETAFFINITIY)
						    set_cpus_allowed_ptr()
	  p->flags |= PF_NO_SETAFFINITY

Fix the bug by putting everything under the regular scheduler locks.

This also closes a hole in the serialization of task_struct::{nr_,}cpus_allowed.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dedekind1@gmail.com
Cc: juri.lelli@arm.com
Cc: mgorman@suse.de
Cc: riel@redhat.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20150515154833.545640346@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Peter Zijlstra   authored and   Ingo Molnar   commited 2015-08-12 12:06:09 +02:00
25834c73f9
workqueue: Make flush_workqueue() available again to non GPL modules
Commit 37b1ef31a5 ("workqueue: move
flush_scheduled_work() to workqueue.h") moved the exported non GPL
flush_scheduled_work() from a function to an inline wrapper.
Unfortunately, it directly calls flush_workqueue() which is a GPL function.
This has the effect of changing the licensing requirement for this function
and makes it unavailable to non GPL modules.

See commit ad7b1f841f ("workqueue: Make
schedule_work() available again to non GPL modules") for precedent.

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Tim Gardner   authored and   Tejun Heo   commited 2015-08-04 14:04:54 -04:00
1dadafa86a
rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()
This commit renames rcu_lockdep_assert() to RCU_LOCKDEP_WARN() for
consistency with the WARN() series of macros.  This also requires
inverting the sense of the conditional, which this commit also does.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Paul E. McKenney   commited 2015-07-22 15:27:32 -07:00
f78f5b90c4
Minor merge needed, due to function move.
Main excitement here is Peter Zijlstra's lockless rbtree optimization to
 speed module address lookup.  He found some abusers of the module lock
 doing that too.
 
 A little bit of parameter work here too; including Dan Streetman's breaking
 up the big param mutex so writing a parameter can load another module (yeah,
 really).  Unfortunately that broke the usual suspects, !CONFIG_MODULES and
 !CONFIG_SYSFS, so those fixes were appended too.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...

Linus Torvalds   commited 2015-07-01 10:49:25 -07:00
02201e3f1b
workqueue: fix typos in comments
tj: dropped iff -> if, iff is if and only if not a typo.  Spotted by
    Randy Dunlap.

Signed-off-by: Shailendra Verma <shailendra.capricorn@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>

Shailendra Verma   authored and   Tejun Heo   commited 2015-05-29 09:20:01 -04:00
402dd89d6c
kernel/workqueue.c: remove ifdefs over wq_power_efficient
We can avoid an ifdef over wq_power_efficient's declaration
by just using IS_ENABLED().

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: cocci@systeme.lip6.fr
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Luis R. Rodriguez   authored and   Rusty Russell   commited 2015-05-28 11:32:12 +09:30
552f530cbc
workqueue: move flush_scheduled_work() to workqueue.h
flush_scheduled_work() is just a simple call to flush_work().

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Lai Jiangshan   authored and   Tejun Heo   commited 2015-05-21 17:26:22 -04:00
37b1ef31a5
workqueue: remove the lock from wq_sysfs_prep_attrs()
Reading to wq->unbound_attrs requires protection of either wq_pool_mutex
or wq->mutex, and wq_sysfs_prep_attrs() is called with wq_pool_mutex held,
so we don't need to grab wq->mutex here.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Lai Jiangshan   authored and   Tejun Heo   commited 2015-05-21 17:26:22 -04:00
899a94fe15
workqueue: remove the declaration of copy_workqueue_attrs()
This pre-declaration was unneeded since a previous refactor patch
6ba94429c8 ("workqueue: Reorder sysfs code").

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Lai Jiangshan   authored and   Tejun Heo   commited 2015-05-21 17:26:22 -04:00
da7f91b2e2
workqueue: ensure attrs changes are properly synchronized
Current modification to attrs via sysfs is not fully synchronized.

Process A (change cpumask)      | Process B (change numa affinity)
wq_cpumask_store()              |
  wq_sysfs_prep_attrs()         |
                                | apply_workqueue_attrs()
  apply_workqueue_attrs()       |

It results that the Process B's operation is totally reverted
without any notification, it is a buggy behavior.  So this patch
moves wq_sysfs_prep_attrs() into the protection under wq_pool_mutex
to ensure attrs changes are properly synchronized.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Lai Jiangshan   authored and   Tejun Heo   commited 2015-05-19 17:37:00 -04:00
d4d3e25797
workqueue: separate out and refactor the locking of applying attrs
Applying attrs requires two locks: get_online_cpus() and wq_pool_mutex,
and this code is duplicated at two places (apply_workqueue_attrs() and
workqueue_set_unbound_cpumask()).  So we separate out this locking
code into apply_wqattrs_[un]lock() and do a minor refactor on
apply_workqueue_attrs().

The apply_wqattrs_[un]lock() will be also used on later patch for
ensuring attrs changes are properly synchronized.

tj: minor updates to comments

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Lai Jiangshan   authored and   Tejun Heo   commited 2015-05-19 17:37:00 -04:00
a0111cf671