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[resnostyle <bwp.pearson@xxxxxxxxx>]

In my particular scenario I am using Ubuntu 14.04. With NFS mount and
AUFS. And am seeing the same result of kworker0:1 going to and staying
100%. I have tried adjusting the acpi settings to off, but this has not
helped.

Rebooting the server itself does not help. I'll post any needed logs to
help fixing it.

Turning off nfs-server has helped.

-----

I am running kernel 3.13.0-19-generic.

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https://bugs.launchpad.net/bugs/1318116

Title:
  kworker uses 100% CPU when nfs-kernel-server is active

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  I have a clean install of 14.04 on an i7-860 with 16GB RAM.

  I'm using NFS to share a home directory.  The volume is ~2TB,
  formatted JFS, and it has a single client.

  I recently noticed that I had a [kworker] process using 100% CPU:

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                      
   9253 root      20   0       0      0      0 R  99.9  0.0   0:30.17 [kworker/3:1]                

  Rebooting didn't help.

  After some troubleshooting I found that it went away immediately when
  I stopped the nfs-kernel-server daemon.  When I start it, it comes
  back after a minute or two, still using 99-100% CPU.  The load goes
  away when the client is turned off and the NFS server is restarted,
  but it comes back as soon as it reconnects.

  The only line in /etc/exports is:
  /home 192.168.1.0/24(rw,sync,no_root_squash)

  version_signature:
  Ubuntu 3.13.0-24.47-generic 3.13.9


  # dpkg -l nfs-kernel-server
  Desired=Unknown/Install/Remove/Purge/Hold
  | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
  |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
  ||/ Name           Version      Architecture Description
  +++-==============-============-============-==================================
  ii  nfs-kernel-ser 1:1.2.8-6ubu amd64        support for NFS kernel server

  
  Description:    Ubuntu 14.04 LTS
  Release:        14.04

  
  I don't think this is related to my hardware but I can provide lspci output if necessary.
  --- 
  ApportVersion: 2.14.1-0ubuntu3
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC1:  gdexter    4414 F.... pulseaudio
                        gdexter    4778 F.... pulseaudio
   /dev/snd/controlC0:  gdexter    4414 F.... pulseaudio
                        gdexter    4778 F.... pulseaudio
  DistroRelease: Ubuntu 14.04
  HibernationDevice: RESUME=UUID=de6e2d52-86c9-4867-8d37-31964953e1e6
  InstallationDate: Installed on 2014-05-01 (9 days ago)
  InstallationMedia: Kubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.1)
  IwConfig:
   eth0      no wireless extensions.
   
   eth1      no wireless extensions.
   
   lo        no wireless extensions.
  MachineType: Gigabyte Technology Co., Ltd. P55A-UD4P
  NonfreeKernelModules: nvidia
  Package: linux (not installed)
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB:
   
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-24-generic root=/dev/mapper/hostname-newestroot ro quiet splash
  ProcVersionSignature: Ubuntu 3.13.0-24.47-generic 3.13.9
  PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-24-generic N/A
   linux-backports-modules-3.13.0-24-generic  N/A
   linux-firmware                             1.127
  RfKill:
   
  Tags:  trusty
  Uname: Linux 3.13.0-24-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups:
   
  _MarkForUpload: True
  dmi.bios.date: 10/16/2009
  dmi.bios.vendor: Award Software International, Inc.
  dmi.bios.version: F3
  dmi.board.name: P55A-UD4P
  dmi.board.vendor: Gigabyte Technology Co., Ltd.
  dmi.board.version: x.x
  dmi.chassis.type: 3
  dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
  dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF3:bd10/16/2009:svnGigabyteTechnologyCo.,Ltd.:pnP55A-UD4P:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnP55A-UD4P:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
  dmi.product.name: P55A-UD4P
  dmi.sys.vendor: Gigabyte Technology Co., Ltd.

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