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
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>
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>
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>
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")
Pull MIPS updates from Ralf Baechle:
"This is the main pull request for MIPS for 4.5 plus some 4.4 fixes.
The executive summary:
- ATH79 platform improvments, use DT bindings for the ATH79 USB PHY.
- Avoid useless rebuilds for zboot.
- jz4780: Add NEMC, BCH and NAND device tree nodes
- Initial support for the MicroChip's DT platform. As all the device
drivers are missing this is still of limited use.
- Some Loongson3 cleanups.
- The unavoidable whitespace polishing.
- Reduce clock skew when synchronizing the CPU cycle counters on CPU
startup.
- Add MIPS R6 fixes.
- Lots of cleanups across arch/mips as fallout from KVM.
- Lots of minor fixes and changes for IEEE 754-2008 support to the
FPU emulator / fp-assist software.
- Minor Ralink, BCM47xx and bcm963xx platform support improvments.
- Support SMP on BCM63168"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (84 commits)
MIPS: zboot: Add support for serial debug using the PROM
MIPS: zboot: Avoid useless rebuilds
MIPS: BMIPS: Enable ARCH_WANT_OPTIONAL_GPIOLIB
MIPS: bcm63xx: nvram: Remove unused bcm63xx_nvram_get_psi_size() function
MIPS: bcm963xx: Update bcm_tag field image_sequence
MIPS: bcm963xx: Move extended flash address to bcm_tag header file
MIPS: bcm963xx: Move Broadcom BCM963xx image tag data structure
MIPS: bcm63xx: nvram: Use nvram structure definition from header file
MIPS: bcm963xx: Add Broadcom BCM963xx board nvram data structure
MAINTAINERS: Add KVM for MIPS entry
MIPS: KVM: Add missing newline to kvm_err()
MIPS: Move KVM specific opcodes into asm/inst.h
MIPS: KVM: Use cacheops.h definitions
MIPS: Break down cacheops.h definitions
MIPS: Use EXCCODE_ constants with set_except_vector()
MIPS: Update trap codes
MIPS: Move Cause.ExcCode trap codes to mipsregs.h
MIPS: KVM: Make kvm_mips_{init,exit}() static
MIPS: KVM: Refactor added offsetof()s
MIPS: KVM: Convert EXPORT_SYMBOL to _GPL
...
Pull x86 platform driver updates from Darren Hart:
"Emergency travel prevented me from completing my final testing on this
until today. Nothing here that couldn't wait until RC1 fixes, but I
thought it best to get it out sooner rather than later as it does
contain a build warning fix.
Summary:
A build warning fix, MAINTAINERS cleanup, and a new DMI quirk:
ideapad-laptop:
- Add Lenovo Yoga 700 to no_hw_rfkill dmi list
MAINTAINERS:
- Combine multiple telemetry entries
intel_telemetry_debugfs:
- Fix unused warnings in telemetry debugfs"
* tag 'platform-drivers-x86-v4.5-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
ideapad-laptop: Add Lenovo Yoga 700 to no_hw_rfkill dmi list
MAINTAINERS: Combine multiple telemetry entries
intel_telemetry_debugfs: Fix unused warnings in telemetry debugfs
Pull thermal management updates from Zhang Rui:
"The top merge commit was re-generated yesterday because two topic
branches were dropped from this pull request in the last minute due to
some unaddressed comments. All the other material has been in
linux-next for quite a while.
Specifics:
- Enhance thermal core to handle unexpected device cooling states
after fresh boot and system resume. From Zhang Rui and Chen Yu.
- Several fixes and cleanups on Rockchip and RCAR thermal drivers.
From Caesar Wang and Kuninori Morimoto.
- Add Broxton support for Intel processor thermal reporting device
driver. From Amy Wiles"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
thermal: trip_point_temp_store() calls thermal_zone_device_update()
thermal: rcar: rcar_thermal_get_temp() return error if strange temp
thermal: rcar: check irq possibility in rcar_thermal_irq_xxx()
thermal: rcar: check every rcar_thermal_update_temp() return value
thermal: rcar: move rcar_thermal_dt_ids to upside
thermal: rockchip: Support the RK3399 SoCs in thermal driver
thermal: rockchip: Support the RK3228 SoCs in thermal driver
dt-bindings: rockchip-thermal: Support the RK3228/RK3399 SoCs compatible
thermal: rockchip: fix a trivial typo
Thermal: Enable Broxton SoC thermal reporting device
thermal: constify pch_dev_ops structure
Thermal: do thermal zone update after a cooling device registered
Thermal: handle thermal zone device properly during system sleep
Thermal: initialize thermal zone device correctly
Pull 9p updates from Eric Van Hensbergen:
"Sorry for the last minute pull request, there's was a change that
didn't get pulled into for-next until two weeks ago and I wanted to
give it some bake time.
Summary:
Rework and error handling fixes, primarily in the fscatch and fd
transports"
* tag 'for-linus-4.5-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
fs/9p: use fscache mutex rather than spinlock
9p: trans_fd, bail out if recv fcall if missing
9p: trans_fd, read rework to use p9_parse_header
net/9p: Add device name details on error
Pull Ceph updates from Sage Weil:
"The two main changes are aio support in CephFS, and a series that
fixes several issues in the authentication key timeout/renewal code.
On top of that are a variety of cleanups and minor bug fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
libceph: remove outdated comment
libceph: kill off ceph_x_ticket_handler::validity
libceph: invalidate AUTH in addition to a service ticket
libceph: fix authorizer invalidation, take 2
libceph: clear messenger auth_retry flag if we fault
libceph: fix ceph_msg_revoke()
libceph: use list_for_each_entry_safe
ceph: use i_size_{read,write} to get/set i_size
ceph: re-send AIO write request when getting -EOLDSNAP error
ceph: Asynchronous IO support
ceph: Avoid to propagate the invalid page point
ceph: fix double page_unlock() in page_mkwrite()
rbd: delete an unnecessary check before rbd_dev_destroy()
libceph: use list_next_entry instead of list_entry_next
ceph: ceph_frag_contains_value can be boolean
ceph: remove unused functions in ceph_frag.h
Pull SMB3 fixes from Steve French:
"A collection of CIFS/SMB3 fixes.
It includes a couple bug fixes, a few for improved debugging of
cifs.ko and some improvements to the way cifs does key generation.
I do have some additional bug fixes I expect in the next week or two
(to address a problem found by xfstest, and some fixes for SMB3.11
dialect, and a couple patches that just came in yesterday that I am
reviewing)"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
cifs_dbg() outputs an uninitialized buffer in cifs_readdir()
cifs: fix race between call_async() and reconnect()
Prepare for encryption support (first part). Add decryption and encryption key generation. Thanks to Metze for helping with this.
cifs: Allow using O_DIRECT with cache=loose
cifs: Make echo interval tunable
cifs: Check uniqueid for SMB2+ and return -ESTALE if necessary
Print IP address of unresponsive server
cifs: Ratelimit kernel log messages
This patch fixes compile time warnings when CONFIG_PM_SLEEP
is undefined. In this case sleep related counters are unused.
Signed-off-by: Souvik Kumar Chakravarty <souvik.k.chakravarty@intel.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
If we detect that there is nothing to do just set the flag and do not
check if it was already set before. Races really do not matter. If the
flag is set by any code then the shepherd will start dealing with the
situation and reenable the vmstat workers when necessary again.
Since commit 0eb77e9880 ("vmstat: make vmstat_updater deferrable again
and shut down on idle") quiet_vmstat might update cpu_stat_off and mark
a particular cpu to be handled by vmstat_shepherd. This might trigger a
VM_BUG_ON in vmstat_update because the work item might have been
sleeping during the idle period and see the cpu_stat_off updated after
the wake up. The VM_BUG_ON is therefore misleading and no more
appropriate. Moreover it doesn't really suite any protection from real
bugs because vmstat_shepherd will simply reschedule the vmstat_work
anytime it sees a particular cpu set or vmstat_update would do the same
from the worker context directly. Even when the two would race the
result wouldn't be incorrect as the counters update is fully idempotent.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tejun Heo
Mike Galbraith
Linus Torvalds
Josh Boyer
Souvik Kumar Chakravarty
Christoph Lameter
Ralf Baechle
Alban Bedel
Florian Fainelli
Simon Arlott