Changes in 5.15.63
ALSA: info: Fix llseek return value when using callback
ALSA: hda/realtek: Add quirk for Clevo NS50PU, NS70PU
KVM: Unconditionally get a ref to /dev/kvm module when creating a VM
x86/mm: Use proper mask when setting PUD mapping
rds: add missing barrier to release_refill
locking/atomic: Make test_and_*_bit() ordered on failure
drm/nouveau: recognise GA103
drm/ttm: Fix dummy res NULL ptr deref bug
drm/amd/display: Check correct bounds for stream encoder instances for DCN303
ata: libata-eh: Add missing command name
mmc: pxamci: Fix another error handling path in pxamci_probe()
mmc: pxamci: Fix an error handling path in pxamci_probe()
mmc: meson-gx: Fix an error handling path in meson_mmc_probe()
btrfs: unset reloc control if transaction commit fails in prepare_to_relocate()
btrfs: reset RO counter on block group if we fail to relocate
btrfs: fix lost error handling when looking up extended ref on log replay
cifs: Fix memory leak on the deferred close
x86/kprobes: Fix JNG/JNLE emulation
tracing/perf: Fix double put of trace event when init fails
tracing/eprobes: Do not allow eprobes to use $stack, or % for regs
tracing/eprobes: Do not hardcode $comm as a string
tracing/eprobes: Have event probes be consistent with kprobes and uprobes
tracing/probes: Have kprobes and uprobes use $COMM too
tracing: Have filter accept "common_cpu" to be consistent
ALSA: usb-audio: More comprehensive mixer map for ASUS ROG Zenith II
dt-bindings: usb: mtk-xhci: Allow wakeup interrupt-names to be optional
can: ems_usb: fix clang's -Wunaligned-access warning
apparmor: fix quiet_denied for file rules
apparmor: fix absroot causing audited secids to begin with =
apparmor: Fix failed mount permission check error message
apparmor: fix aa_label_asxprint return check
apparmor: fix setting unconfined mode on a loaded profile
apparmor: fix overlapping attachment computation
apparmor: fix reference count leak in aa_pivotroot()
apparmor: Fix memleak in aa_simple_write_to_buffer()
Documentation: ACPI: EINJ: Fix obsolete example
NFSv4.1: Don't decrease the value of seq_nr_highest_sent
NFSv4.1: Handle NFS4ERR_DELAY replies to OP_SEQUENCE correctly
NFSv4: Fix races in the legacy idmapper upcall
NFSv4.1: RECLAIM_COMPLETE must handle EACCES
NFSv4/pnfs: Fix a use-after-free bug in open
BPF: Fix potential bad pointer dereference in bpf_sys_bpf()
bpf: Don't reinit map value in prealloc_lru_pop
bpf: Acquire map uref in .init_seq_private for array map iterator
bpf: Acquire map uref in .init_seq_private for hash map iterator
bpf: Acquire map uref in .init_seq_private for sock local storage map iterator
bpf: Acquire map uref in .init_seq_private for sock{map,hash} iterator
bpf: Check the validity of max_rdwr_access for sock local storage map iterator
can: mcp251x: Fix race condition on receive interrupt
can: j1939: j1939_session_destroy(): fix memory leak of skbs
net: atlantic: fix aq_vec index out of range error
m68k: coldfire/device.c: protect FLEXCAN blocks
sunrpc: fix expiry of auth creds
SUNRPC: Fix xdr_encode_bool()
SUNRPC: Reinitialise the backchannel request buffers before reuse
virtio_net: fix memory leak inside XPD_TX with mergeable
devlink: Fix use-after-free after a failed reload
net: phy: Warn about incorrect mdio_bus_phy_resume() state
net: bcmgenet: Indicate MAC is in charge of PHY PM
net: bgmac: Fix a BUG triggered by wrong bytes_compl
selftests: forwarding: Fix failing tests with old libnet
dt-bindings: arm: qcom: fix Alcatel OneTouch Idol 3 compatibles
pinctrl: nomadik: Fix refcount leak in nmk_pinctrl_dt_subnode_to_map
pinctrl: qcom: msm8916: Allow CAMSS GP clocks to be muxed
pinctrl: amd: Don't save/restore interrupt status and wake status bits
pinctrl: sunxi: Add I/O bias setting for H6 R-PIO
pinctrl: qcom: sm8250: Fix PDC map
Input: exc3000 - fix return value check of wait_for_completion_timeout
octeontx2-pf: Fix NIX_AF_TL3_TL2X_LINKX_CFG register configuration
octeontx2-af: Apply tx nibble fixup always
octeontx2-af: suppress external profile loading warning
octeontx2-af: Fix mcam entry resource leak
octeontx2-af: Fix key checking for source mac
ACPI: property: Return type of acpi_add_nondev_subnodes() should be bool
geneve: do not use RT_TOS for IPv6 flowlabel
mlx5: do not use RT_TOS for IPv6 flowlabel
ipv6: do not use RT_TOS for IPv6 flowlabel
plip: avoid rcu debug splat
vsock: Fix memory leak in vsock_connect()
vsock: Set socket state back to SS_UNCONNECTED in vsock_connect_timeout()
dt-bindings: gpio: zynq: Add missing compatible strings
dt-bindings: arm: qcom: fix Longcheer L8150 compatibles
dt-bindings: arm: qcom: fix MSM8916 MTP compatibles
dt-bindings: arm: qcom: fix MSM8994 boards compatibles
dt-bindings: clock: qcom,gcc-msm8996: add more GCC clock sources
spi: dt-bindings: cadence: add missing 'required'
spi: dt-bindings: zynqmp-qspi: add missing 'required'
ceph: use correct index when encoding client supported features
tools/vm/slabinfo: use alphabetic order when two values are equal
ceph: don't leak snap_rwsem in handle_cap_grant
kbuild: dummy-tools: avoid tmpdir leak in dummy gcc
tools build: Switch to new openssl API for test-libcrypto
NTB: ntb_tool: uninitialized heap data in tool_fn_write()
nfp: ethtool: fix the display error of `ethtool -m DEVNAME`
xen/xenbus: fix return type in xenbus_file_read()
atm: idt77252: fix use-after-free bugs caused by tst_timer
geneve: fix TOS inheriting for ipv4
perf probe: Fix an error handling path in 'parse_perf_probe_command()'
perf parse-events: Fix segfault when event parser gets an error
perf tests: Fix Track with sched_switch test for hybrid case
dpaa2-eth: trace the allocated address instead of page struct
fs/ntfs3: Fix using uninitialized value n when calling indx_read
fs/ntfs3: Fix NULL deref in ntfs_update_mftmirr
fs/ntfs3: Don't clear upper bits accidentally in log_replay()
fs/ntfs3: Fix double free on remount
fs/ntfs3: Do not change mode if ntfs_set_ea failed
fs/ntfs3: Fix missing i_op in ntfs_read_mft
nios2: page fault et.al. are *not* restartable syscalls...
nios2: don't leave NULLs in sys_call_table[]
nios2: traced syscall does need to check the syscall number
nios2: fix syscall restart checks
nios2: restarts apply only to the first sigframe we build...
nios2: add force_successful_syscall_return()
iavf: Fix adminq error handling
iavf: Fix reset error handling
ASoC: SOF: debug: Fix potential buffer overflow by snprintf()
ASoC: tas2770: Set correct FSYNC polarity
ASoC: tas2770: Allow mono streams
ASoC: tas2770: Drop conflicting set_bias_level power setting
ASoC: tas2770: Fix handling of mute/unmute
ASoC: codec: tlv320aic32x4: fix mono playback via I2S
netfilter: nf_tables: use READ_ONCE and WRITE_ONCE for shared generation id access
fs/ntfs3: uninitialized variable in ntfs_set_acl_ex()
netfilter: nf_tables: disallow NFTA_SET_ELEM_KEY_END with NFT_SET_ELEM_INTERVAL_END flag
netfilter: nf_tables: possible module reference underflow in error path
netfilter: nf_tables: really skip inactive sets when allocating name
netfilter: nf_tables: validate NFTA_SET_ELEM_OBJREF based on NFT_SET_OBJECT flag
netfilter: nf_tables: NFTA_SET_ELEM_KEY_END requires concat and interval flags
netfilter: nf_tables: disallow NFT_SET_ELEM_CATCHALL and NFT_SET_ELEM_INTERVAL_END
netfilter: nf_tables: check NFT_SET_CONCAT flag if field_count is specified
powerpc/pci: Fix get_phb_number() locking
spi: meson-spicc: add local pow2 clock ops to preserve rate between messages
net/sunrpc: fix potential memory leaks in rpc_sysfs_xprt_state_change()
net: dsa: mv88e6060: prevent crash on an unused port
mlxsw: spectrum: Clear PTP configuration after unregistering the netdevice
net: moxa: pass pdev instead of ndev to DMA functions
net: fix potential refcount leak in ndisc_router_discovery()
net: dsa: microchip: ksz9477: fix fdb_dump last invalid entry
net: dsa: felix: fix ethtool 256-511 and 512-1023 TX packet counters
net: genl: fix error path memory leak in policy dumping
net: dsa: don't warn in dsa_port_set_state_now() when driver doesn't support it
net: dsa: sja1105: fix buffer overflow in sja1105_setup_devlink_regions()
ice: Ignore EEXIST when setting promisc mode
i2c: imx: Make sure to unregister adapter on remove()
regulator: pca9450: Remove restrictions for regulator-name
i40e: Fix to stop tx_timeout recovery if GLOBR fails
fec: Fix timer capture timing in `fec_ptp_enable_pps()`
stmmac: intel: Add a missing clk_disable_unprepare() call in intel_eth_pci_remove()
igb: Add lock to avoid data race
kbuild: fix the modules order between drivers and libs
gcc-plugins: Undefine LATENT_ENTROPY_PLUGIN when plugin disabled for a file
tracing/eprobes: Fix reading of string fields
drm/imx/dcss: get rid of HPD warning message
ASoC: SOF: Intel: hda: Define rom_status_reg in sof_intel_dsp_desc
ASoC: SOF: Intel: hda: Fix potential buffer overflow by snprintf()
drm/meson: Fix refcount bugs in meson_vpu_has_available_connectors()
drm/sun4i: dsi: Prevent underflow when computing packet sizes
net: qrtr: start MHI channel after endpoit creation
KVM: arm64: Treat PMCR_EL1.LC as RES1 on asymmetric systems
KVM: arm64: Reject 32bit user PSTATE on asymmetric systems
HID: multitouch: new device class fix Lenovo X12 trackpad sticky
PCI: Add ACS quirk for Broadcom BCM5750x NICs
platform/chrome: cros_ec_proto: don't show MKBP version if unsupported
usb: cdns3 fix use-after-free at workaround 2
usb: cdns3: fix random warning message when driver load
usb: gadget: uvc: calculate the number of request depending on framesize
usb: gadget: uvc: call uvc uvcg_warn on completed status instead of uvcg_info
PCI: aardvark: Fix reporting Slot capabilities on emulated bridge
irqchip/tegra: Fix overflow implicit truncation warnings
drm/meson: Fix overflow implicit truncation warnings
clk: ti: Stop using legacy clkctrl names for omap4 and 5
scsi: ufs: ufs-mediatek: Fix the timing of configuring device regulators
usb: host: ohci-ppc-of: Fix refcount leak bug
usb: renesas: Fix refcount leak bug
usb: dwc2: gadget: remove D+ pull-up while no vbus with usb-role-switch
vboxguest: Do not use devm for irq
clk: qcom: ipq8074: dont disable gcc_sleep_clk_src
uacce: Handle parent device removal or parent driver module rmmod
zram: do not lookup algorithm in backends table
clk: qcom: clk-alpha-pll: fix clk_trion_pll_configure description
scsi: lpfc: Prevent buffer overflow crashes in debugfs with malformed user input
scsi: lpfc: Fix possible memory leak when failing to issue CMF WQE
gadgetfs: ep_io - wait until IRQ finishes
coresight: etm4x: avoid build failure with unrolled loops
habanalabs/gaudi: fix shift out of bounds
habanalabs/gaudi: mask constant value before cast
mmc: tmio: avoid glitches when resetting
pinctrl: intel: Check against matching data instead of ACPI companion
cxl: Fix a memory leak in an error handling path
PCI/ACPI: Guard ARM64-specific mcfg_quirks
um: add "noreboot" command line option for PANIC_TIMEOUT=-1 setups
dmaengine: dw-axi-dmac: do not print NULL LLI during error
dmaengine: dw-axi-dmac: ignore interrupt if no descriptor
RDMA/rxe: Limit the number of calls to each tasklet
csky/kprobe: reclaim insn_slot on kprobe unregistration
selftests/kprobe: Do not test for GRP/ without event failures
dmaengine: sprd: Cleanup in .remove() after pm_runtime_get_sync() failed
openrisc: io: Define iounmap argument as volatile
phy: samsung: phy-exynos-pcie: sanitize init/power_on callbacks
md: Notify sysfs sync_completed in md_reap_sync_thread()
nvmet-tcp: fix lockdep complaint on nvmet_tcp_wq flush during queue teardown
drivers:md:fix a potential use-after-free bug
ext4: avoid remove directory when directory is corrupted
ext4: avoid resizing to a partial cluster size
lib/list_debug.c: Detect uninitialized lists
tty: serial: Fix refcount leak bug in ucc_uart.c
KVM: PPC: Book3S HV: Fix "rm_exit" entry in debugfs timings
vfio: Clear the caps->buf to NULL after free
mips: cavium-octeon: Fix missing of_node_put() in octeon2_usb_clocks_start
iommu/io-pgtable-arm-v7s: Add a quirk to allow pgtable PA up to 35bit
modules: Ensure natural alignment for .altinstructions and __bug_table sections
ASoC: rsnd: care default case on rsnd_ssiu_busif_err_irq_ctrl()
riscv: dts: sifive: Add fu740 topology information
riscv: dts: canaan: Add k210 topology information
riscv: mmap with PROT_WRITE but no PROT_READ is invalid
RISC-V: Add fast call path of crash_kexec()
watchdog: export lockup_detector_reconfigure
powerpc/32: Set an IBAT covering up to _einittext during init
powerpc/32: Don't always pass -mcpu=powerpc to the compiler
ovl: warn if trusted xattr creation fails
powerpc/ioda/iommu/debugfs: Generate unique debugfs entries
ALSA: core: Add async signal helpers
ALSA: timer: Use deferred fasync helper
ALSA: control: Use deferred fasync helper
f2fs: fix to avoid use f2fs_bug_on() in f2fs_new_node_page()
f2fs: fix to do sanity check on segment type in build_sit_entries()
smb3: check xattr value length earlier
powerpc/64: Init jump labels before parse_early_param()
venus: pm_helpers: Fix warning in OPP during probe
video: fbdev: i740fb: Check the argument of i740_calc_vclk()
MIPS: tlbex: Explicitly compare _PAGE_NO_EXEC against 0
can: j1939: j1939_sk_queue_activate_next_locked(): replace WARN_ON_ONCE with netdev_warn_once()
scsi: ufs: ufs-mediatek: Fix build error and type mismatch
xfs: flush inodegc workqueue tasks before cancel
xfs: reserve quota for dir expansion when linking/unlinking files
xfs: reserve quota for target dir expansion when renaming files
xfs: remove infinite loop when reserving free block pool
xfs: always succeed at setting the reserve pool size
xfs: fix overfilling of reserve pool
xfs: fix soft lockup via spinning in filestream ag selection loop
xfs: revert "xfs: actually bump warning counts when we send warnings"
xfs: reject crazy array sizes being fed to XFS_IOC_GETBMAP*
Linux 5.15.63
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I85d0cf74054be9e400907eac7d8f2d4d85914f6f
[ Upstream commit 7c56a8733d0a2a4be2438a7512566e5ce552fccf ]
In some circumstances it may be interesting to reconfigure the watchdog
from inside the kernel.
On PowerPC, this may helpful before and after a LPAR migration (LPM) is
initiated, because it implies some latencies, watchdog, and especially NMI
watchdog is expected to be triggered during this operation. Reconfiguring
the watchdog with a factor, would prevent it to happen too frequently
during LPM.
Rename lockup_detector_reconfigure() as __lockup_detector_reconfigure() and
create a new function lockup_detector_reconfigure() calling
__lockup_detector_reconfigure() under the protection of watchdog_mutex.
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
[mpe: Squash in build fix from Laurent, reported by Sachin]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220713154729.80789-3-ldufour@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Add hook to gather data of softlockup and summarize it with
other information.
Bug: 222638752
Signed-off-by: Sangmoon Kim <sangmoon.kim@samsung.com>
Change-Id: I5263bbd573c3fa4b4c981ac26c943721ce09506d
Commit 9bf3bc949f ("watchdog: cleanup handling of false positives")
tried to handle a virtual host stopped by the host a more
straightforward and cleaner way.
But it introduced a risk of false softlockup reports. The virtual host
might be stopped at any time, for example between
kvm_check_and_clear_guest_paused() and is_softlockup(). As a result,
is_softlockup() might read the updated jiffies and detects a softlockup.
A solution might be to put back kvm_check_and_clear_guest_paused() after
is_softlockup() and detect it. But it would put back the cycle that
complicates the logic.
In fact, the handling of all the timestamps is not reliable. The code
does not guarantee when and how many times the timestamps are read. For
example, "period_ts" might be touched anytime also from NMI and re-read in
is_softlockup(). It works just by chance.
Fix all the problems by making the code even more explicit.
1. Make sure that "now" and "period_ts" timestamps are read only once.
They might be changed at anytime by NMI or when the virtual guest is
stopped by the host. Note that "now" timestamp does this implicitly
because "jiffies" is marked volatile.
2. "now" time must be read first. The state of "period_ts" will
decide whether it will be used or the period will get restarted.
3. kvm_check_and_clear_guest_paused() must be called before reading
"period_ts". It touches the variable when the guest was stopped.
As a result, "now" timestamp is used only when the watchdog was not
touched and the guest not stopped in the meantime. "period_ts" is
restarted in all other situations.
Link: https://lkml.kernel.org/r/YKT55gw+RZfyoFf7@alley
Fixes: 9bf3bc949f ("watchdog: cleanup handling of false positives")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit d6ad3e286d ("softlockup: Add sched_clock_tick() to avoid kernel
warning on kgdb resume") introduced touch_softlockup_watchdog_sync().
It solved a problem when the watchdog was touched in an atomic context,
the timer callback was proceed right after releasing interrupts, and the
local clock has not been updated yet. In this case, sched_clock_tick()
was called in watchdog_timer_fn() before updating the timer.
So far so good.
Later commit 5d1c0f4a80 ("watchdog: add check for suspended vm in
softlockup detector") added two kvm_check_and_clear_guest_paused()
calls. They touch the watchdog when the guest has been sleeping.
The code makes my head spin around.
Scenario 1:
+ guest did sleep:
+ PVCLOCK_GUEST_STOPPED is set
+ 1st watchdog_timer_fn() invocation:
+ the watchdog is not touched yet
+ is_softlockup() returns too big delay
+ kvm_check_and_clear_guest_paused():
+ clear PVCLOCK_GUEST_STOPPED
+ call touch_softlockup_watchdog_sync()
+ set SOFTLOCKUP_DELAY_REPORT
+ set softlockup_touch_sync
+ return from the timer callback
+ 2nd watchdog_timer_fn() invocation:
+ call sched_clock_tick() even though it is not needed.
The timer callback was invoked again only because the clock
has already been updated in the meantime.
+ call kvm_check_and_clear_guest_paused() that does nothing
because PVCLOCK_GUEST_STOPPED has been cleared already.
+ call update_report_ts() and return. This is fine. Except
that sched_clock_tick() might allow to set it already
during the 1st invocation.
Scenario 2:
+ guest did sleep
+ 1st watchdog_timer_fn() invocation
+ same as in 1st scenario
+ guest did sleep again:
+ set PVCLOCK_GUEST_STOPPED again
+ 2nd watchdog_timer_fn() invocation
+ SOFTLOCKUP_DELAY_REPORT is set from 1st invocation
+ call sched_clock_tick()
+ call kvm_check_and_clear_guest_paused()
+ clear PVCLOCK_GUEST_STOPPED
+ call touch_softlockup_watchdog_sync()
+ set SOFTLOCKUP_DELAY_REPORT
+ set softlockup_touch_sync
+ call update_report_ts() (set real timestamp immediately)
+ return from the timer callback
+ 3rd watchdog_timer_fn() invocation
+ timestamp is set from 2nd invocation
+ softlockup_touch_sync is set but not checked because
the real timestamp is already set
Make the code more straightforward:
1. Always call kvm_check_and_clear_guest_paused() at the very
beginning to handle PVCLOCK_GUEST_STOPPED. It touches the watchdog
when the quest did sleep.
2. Handle the situation when the watchdog has been touched
(SOFTLOCKUP_DELAY_REPORT is set).
Call sched_clock_tick() when touch_*sync() variant was used. It makes
sure that the timestamp will be up to date even when it has been
touched in atomic context or quest did sleep.
As a result, kvm_check_and_clear_guest_paused() is called on a single
location. And the right timestamp is always set when returning from the
timer callback.
Link: https://lkml.kernel.org/r/20210311122130.6788-7-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The softlockup detector does some gymnastic with the variable
soft_watchdog_warn. It was added by the commit 58687acba5
("lockup_detector: Combine nmi_watchdog and softlockup detector").
The purpose is not completely clear. There are the following clues. They
describe the situation how it looked after the above mentioned commit:
1. The variable was checked with a comment "only warn once".
2. The variable was set when softlockup was reported. It was cleared
only when the CPU was not longer in the softlockup state.
3. watchdog_touch_ts was not explicitly updated when the softlockup
was reported. Without this variable, the report would normally
be printed again during every following watchdog_timer_fn()
invocation.
The logic has got even more tangled up by the commit ed235875e2
("kernel/watchdog.c: print traces for all cpus on lockup detection").
After this commit, soft_watchdog_warn is set only when
softlockup_all_cpu_backtrace is enabled. But multiple reports from all
CPUs are prevented by a new variable soft_lockup_nmi_warn.
Conclusion:
The variable probably never worked as intended. In each case, it has not
worked last many years because the softlockup was reported repeatedly
after the full period defined by watchdog_thresh.
The reason is that watchdog gets touched in many known slow paths, for
example, in printk_stack_address(). This code is called also when
printing the softlockup report. It means that the watchdog timestamp gets
updated after each report.
Solution:
Simply remove the logic. People want the periodic report anyway.
Link: https://lkml.kernel.org/r/20210311122130.6788-5-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The softlockup detector currently shows the time spent since the last
report. As a result it is not clear whether a CPU is infinitely hogged by
a single task or if it is a repeated event.
The situation can be simulated with a simply busy loop:
while (true)
cpu_relax();
The softlockup detector produces:
[ 168.277520] watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [cat:4865]
[ 196.277604] watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [cat:4865]
[ 236.277522] watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [cat:4865]
But it should be, something like:
[ 480.372418] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [cat:4943]
[ 508.372359] watchdog: BUG: soft lockup - CPU#2 stuck for 52s! [cat:4943]
[ 548.372359] watchdog: BUG: soft lockup - CPU#2 stuck for 89s! [cat:4943]
[ 576.372351] watchdog: BUG: soft lockup - CPU#2 stuck for 115s! [cat:4943]
For the better output, add an additional timestamp of the last report.
Only this timestamp is reset when the watchdog is intentionally touched
from slow code paths or when printing the report.
Link: https://lkml.kernel.org/r/20210311122130.6788-4-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The softlockup situation might stay for a long time or even forever. When
it happens, the softlockup debug messages are printed in regular intervals
defined by get_softlockup_thresh().
There is a mystery. The repeated message is printed after the full
interval that is defined by get_softlockup_thresh(). But the timer
callback is called more often as defined by sample_period. The code looks
like the soflockup should get reported in every sample_period when it was
once behind the thresh.
It works only by chance. The watchdog is touched when printing the stall
report, for example, in printk_stack_address().
Make the behavior clear and predictable by explicitly updating the
timestamp in watchdog_timer_fn() when the report gets printed.
Link: https://lkml.kernel.org/r/20210311122130.6788-3-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "watchdog/softlockup: Report overall time and some cleanup", v2.
I dug deep into the softlockup watchdog history when time permitted this
year. And reworked the patchset that fixed timestamps and cleaned up the
code[2].
I split it into very small steps and did even more code clean up. The
result looks quite strightforward and I am pretty confident with the
changes.
[1] v2: https://lore.kernel.org/r/20201210160038.31441-1-pmladek@suse.com
[2] v1: https://lore.kernel.org/r/20191024114928.15377-1-pmladek@suse.com
This patch (of 6):
There are many touch_*watchdog() functions. They are called in situations
where the watchdog could report false positives or create unnecessary
noise. For example, when CPU is entering idle mode, a virtual machine is
stopped, or a lot of messages are printed in the atomic context.
These functions set SOFTLOCKUP_RESET instead of a real timestamp. It
allows to call them even in a context where jiffies might be outdated.
For example, in an atomic context.
The real timestamp is set by __touch_watchdog() that is called from the
watchdog timer callback.
Rename this callback to update_touch_ts(). It better describes the effect
and clearly distinguish is from the other touch_*watchdog() functions.
Another motivation is that two timestamps are going to be used. One will
be used for the total softlockup time. The other will be used to measure
time since the last report. The new function name will help to
distinguish which timestamp is being updated.
Link: https://lkml.kernel.org/r/20210311122130.6788-1-pmladek@suse.com
Link: https://lkml.kernel.org/r/20210311122130.6788-2-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
84;0;0c84;0;0c
There are two workqueue-specific watchdog timestamps:
+ @wq_watchdog_touched_cpu (per-CPU) updated by
touch_softlockup_watchdog()
+ @wq_watchdog_touched (global) updated by
touch_all_softlockup_watchdogs()
watchdog_timer_fn() checks only the global @wq_watchdog_touched for
unbound workqueues. As a result, unbound workqueues are not aware
of touch_softlockup_watchdog(). The watchdog might report a stall
even when the unbound workqueues are blocked by a known slow code.
Solution:
touch_softlockup_watchdog() must touch also the global @wq_watchdog_touched
timestamp.
The global timestamp can no longer be used for bound workqueues because
it is now updated from all CPUs. Instead, bound workqueues have to check
only @wq_watchdog_touched_cpu and these timestamps have to be updated for
all CPUs in touch_all_softlockup_watchdogs().
Beware:
The change might cause the opposite problem. An unbound workqueue
might get blocked on CPU A because of a real softlockup. The workqueue
watchdog would miss it when the timestamp got touched on CPU B.
It is acceptable because softlockups are detected by softlockup
watchdog. The workqueue watchdog is there to detect stalls where
a work never finishes, for example, because of dependencies of works
queued into the same workqueue.
V3:
- Modify the commit message clearly according to Petr's suggestion.
Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
After a recent change introduced by Vlastimil's series [0], kernel is
able now to handle sysctl parameters on kernel command line; also, the
series introduced a simple infrastructure to convert legacy boot
parameters (that duplicate sysctls) into sysctl aliases.
This patch converts the watchdog parameters softlockup_panic and
{hard,soft}lockup_all_cpu_backtrace to use the new alias infrastructure.
It fixes the documentation too, since the alias only accepts values 0 or
1, not the full range of integers.
We also took the opportunity here to improve the documentation of the
previously converted hung_task_panic (see the patch series [0]) and put
the alias table in alphabetical order.
[0] http://lkml.kernel.org/r/20200427180433.7029-1-vbabka@suse.cz
Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Link: http://lkml.kernel.org/r/20200507214624.21911-1-gpiccoli@canonical.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.
As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Robert reported that during boot the watchdog timestamp is set to 0 for one
second which is the indicator for a watchdog reset.
The reason for this is that the timestamp is in seconds and the time is
taken from sched clock and divided by ~1e9. sched clock starts at 0 which
means that for the first second during boot the watchdog timestamp is 0,
i.e. reset.
Use ULONG_MAX as the reset indicator value so the watchdog works correctly
right from the start. ULONG_MAX would only conflict with a real timestamp
if the system reaches an uptime of 136 years on 32bit and almost eternity
on 64bit.
Reported-by: Robert Richter <rrichter@marvell.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/87o8v3uuzl.fsf@nanos.tec.linutronix.de
commit 9cf57731b6 ("watchdog/softlockup: Replace "watchdog/%u" threads
with cpu_stop_work") ensures that the watchdog is reliably touched during
a task switch.
As a result the check for an unnoticed task switch is not longer needed.
Remove the relevant code, which effectively reverts commit b1a8de1f53
("softlockup: make detector be aware of task switch of processes hogging
cpu")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20191024114928.15377-2-pmladek@suse.com
sparse complains:
CHECK kernel/watchdog.c
kernel/watchdog.c:45:19: warning: symbol 'nmi_watchdog_available'
was not declared. Should it be static?
kernel/watchdog.c:47:16: warning: symbol 'watchdog_allowed_mask'
was not declared. Should it be static?
They're not referenced by name from anyplace else, make them static.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/7855.1552383228@turing-police
The hard and soft lockup detector threshold has a default value of 10
seconds which can only be changed via sysctl.
During early boot lockup detection can trigger when noisy debugging emits
a large amount of messages to the console, but there is no way to set a
larger threshold on the kernel command line. The detector can only be
completely disabled.
Add a new watchdog_thresh= command line parameter to allow boot time
control over the threshold. It works in the same way as the sysctl and
affects both the soft and the hard lockup detectors.
Signed-off-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: rdunlap@infradead.org
Cc: prarit@redhat.com
Link: https://lkml.kernel.org/r/1541079018-13953-1-git-send-email-loberman@redhat.com
Some architectures need to use stop_machine() to patch functions for
ftrace, and the assumption is that the stopped CPUs do not make function
calls to traceable functions when they are in the stopped state.
Commit ce4f06dcbb ("stop_machine: Touch_nmi_watchdog() after
MULTI_STOP_PREPARE") added calls to the watchdog touch functions from
the stopped CPUs and those functions lack notrace annotations. This
leads to crashes when enabling/disabling ftrace on ARM kernels built
with the Thumb-2 instruction set.
Fix it by adding the necessary notrace annotations.
Fixes: ce4f06dcbb ("stop_machine: Touch_nmi_watchdog() after MULTI_STOP_PREPARE")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: oleg@redhat.com
Cc: tj@kernel.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180821152507.18313-1-vincent.whitchurch@axis.com
Oleg suggested to replace the "watchdog/%u" threads with
cpu_stop_work. That removes one thread per CPU while at the same time
fixes softlockup vs SCHED_DEADLINE.
But more importantly, it does away with the single
smpboot_update_cpumask_percpu_thread() user, which allows
cleanups/shrinkage of the smpboot interface.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function names made sense up to the point where the watchdog
(re)configuration was unified to use softlockup_reconfigure_threads() for
all configuration purposes. But that includes scenarios which solely
configure the nmi watchdog.
Rename softlockup_reconfigure_threads() and softlockup_init_threads() so
the function names match the functionality.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>
The rework of the core hotplug code triggers the WARN_ON in start_wd_cpu()
on powerpc because it is called multiple times for the boot CPU.
The first call is via:
start_wd_on_cpu+0x80/0x2f0
watchdog_nmi_reconfigure+0x124/0x170
softlockup_reconfigure_threads+0x110/0x130
lockup_detector_init+0xbc/0xe0
kernel_init_freeable+0x18c/0x37c
kernel_init+0x2c/0x160
ret_from_kernel_thread+0x5c/0xbc
And then again via the CPU hotplug registration:
start_wd_on_cpu+0x80/0x2f0
cpuhp_invoke_callback+0x194/0x620
cpuhp_thread_fun+0x7c/0x1b0
smpboot_thread_fn+0x290/0x2a0
kthread+0x168/0x1b0
ret_from_kernel_thread+0x5c/0xbc
This can be avoided by setting up the cpu hotplug state with nocalls and
move the initialization to the watchdog_nmi_probe() function. That
initializes the hotplug callbacks without invoking the callback and the
following core initialization function then configures the watchdog for the
online CPUs (in this case CPU0) via softlockup_reconfigure_threads().
Reported-and-tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
The lockup detector reconfiguration tears down all watchdog threads when
the watchdog is disabled and sets them up again when its enabled.
That's a pointless exercise. The watchdog threads are not consuming an
insane amount of resources, so it's enough to set them up at init time and
keep them in parked position when the watchdog is disabled and unpark them
when it is reenabled. The smpboot thread infrastructure takes care of
keeping the force parked threads in place even across cpu hotplug.
Aside of that the code implements the park/unpark facility of smp hotplug
threads on its own, which is even more pointless. We have functionality in
the smpboot thread code to do so.
Use the new thread management functions and get rid of the unholy mess.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194147.470370113@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The lockup detector reconfiguration tears down all watchdog threads when
the watchdog is disabled and sets them up again when its enabled.
That's a pointless exercise. The watchdog threads are not consuming an
insane amount of resources, so it's enough to set them up at init time and
keep them in parked position when the watchdog is disabled and unpark them
when it is reenabled. The smpboot thread infrastructure takes care of
keeping the force parked threads in place even across cpu hotplug.
Another horrible mechanism are the open coded park/unpark loops which are
used for reconfiguration of the watchdog. The smpboot infrastructure allows
exactly the same via smpboot_update_cpumask_thread_percpu(), which is cpu
hotplug safe. Using that instead of the open coded loops allows to get rid
of the hotplug locking mess in the watchdog code.
Implement a clean infrastructure which allows to replace the open coded
nonsense.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194147.377182587@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit:
b94f51183b ("kernel/watchdog: prevent false hardlockup on overloaded system")
tries to fix the following issue:
proc_write()
set_sample_period() <--- New sample period becoms visible
<----- Broken starts
proc_watchdog_update()
watchdog_enable_all_cpus() watchdog_hrtimer_fn()
update_watchdog_all_cpus() restart_timer(sample_period)
watchdog_park_threads()
thread->park()
disable_nmi()
<----- Broken ends
The reason why this is broken is that the update of the watchdog threshold
becomes immediately effective and visible for the hrtimer function which
uses that value to rearm the timer. But the NMI/perf side still uses the
old value up to the point where it is disabled. If the rate has been
lowered then the NMI can run fast enough to 'detect' a hard lockup because
the timer has not fired due to the longer period.
The patch 'fixed' this by adding a variable:
proc_write()
set_sample_period()
<----- Broken starts
proc_watchdog_update()
watchdog_enable_all_cpus() watchdog_hrtimer_fn()
update_watchdog_all_cpus() restart_timer(sample_period)
watchdog_park_threads()
park_in_progress = 1
<----- Broken ends
nmi_watchdog()
if (park_in_progress)
return;
The only effect of this variable was to make the window where the breakage
can hit small enough that it was not longer observable in testing. From a
correctness point of view it is a pointless bandaid which merily papers
over the root cause: the unsychronized update of the variable.
Looking deeper into the related code pathes unearthed similar problems in
the watchdog_start()/stop() functions.
watchdog_start()
perf_nmi_event_start()
hrtimer_start()
watchdog_stop()
hrtimer_cancel()
perf_nmi_event_stop()
In both cases the call order is wrong because if the tasks gets preempted
or the VM gets scheduled out long enough after the first call, then there is
a chance that the next NMI will see a stale hrtimer interrupt count and
trigger a false positive hard lockup splat.
Get rid of park_in_progress so the code can be gradually deobfuscated and
pruned from several layers of duct tape papering over the root cause,
which has been either ignored or not understood at all.
Once this is removed the underlying problem will be fixed by rewriting the
proc interface to do a proper synchronized update.
Address the start/stop() ordering problem as well by reverting the call
order, so this part is at least correct now.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1709052038270.2393@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
