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[Eckhard Wiederhold <ecky@xxxxxxx>]

I confirm as well that this problem persists on Ubuntu 13.10, or more precisely :
[    0.000000] Linux version 3.11.0-13-generic (buildd@roseapple) (gcc version 4.8.1 (Ubuntu/Linaro 4.8.1-10ubuntu8) ) #20-Ubuntu SMP Wed Oct 23 07:38:26 
UTC 2013 (Ubuntu 3.11.0-13.20-generic 3.11.6)

It appears once in a while - about every second day. Last time it
appeared it was today when I plugged in my external Hard-Drive and
logged in afterwards to my allready opened session.

If this happens, there is not much to do about, just reboot and the
problem goes away then but I'm quite reluctant to do it. Tried to kill
it or relaunch the x-server as I thought this process is part of it. But
that seems not to be the case. What are kworkers ? What are they good
for? Do they manage the CPU? This might be the case as I see 3 times 8
of them enumerated from 0 to 7 and four prefixed with u this would
correspond the 8 virtual cores and the 4 real ones present on my CPU.

Might it be possible that there is a race-condition on one of the cores
that puts it to an endless-loop (instead of just letting it die or
blocking it for example)?

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https://bugs.launchpad.net/bugs/887793

Title:
  Kworker constantly taking about 100% CPU

Status in The Linux Kernel:
  Confirmed
Status in “linux” package in Ubuntu:
  Confirmed
Status in “linux” package in Arch Linux:
  New
Status in “linux” package in Suse:
  New

Bug description:
  I've this issue since the latest Ubuntu 11.10 version, all updates
  applied till today, and it's still there. Ubuntu 11.04 did not have
  this issue.

  If I run top there is a Kworker constantly taking much CPU, I don't
  know how to research where this comes from.

  ProblemType: Bug
  DistroRelease: Ubuntu 11.10
  Package: linux-image-3.0.0-12-generic 3.0.0-12.20
  ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
  Uname: Linux 3.0.0-12-generic i686
  AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
  AplayDevices:
   **** List of PLAYBACK Hardware Devices ****
   card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
     Subdevices: 1/1
     Subdevice #0: subdevice #0
  ApportVersion: 1.23-0ubuntu4
  Architecture: i386
  ArecordDevices:
   **** List of CAPTURE Hardware Devices ****
   card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
     Subdevices: 1/1
     Subdevice #0: subdevice #0
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  kp         1473 F.... pulseaudio
  CRDA: Error: [Errno 2] Bestand of map bestaat niet
  Card0.Amixer.info:
   Card hw:0 'Intel'/'HDA Intel at 0xe4404000 irq 46'
     Mixer name	: 'Analog Devices AD1981'
     Components	: 'HDA:11d41981,103c30c0,00100200 HDA:11c11040,103c1378,00100200'
     Controls      : 11
     Simple ctrls  : 9
  Date: Tue Nov  8 22:29:10 2011
  HibernationDevice: RESUME=UUID=ad8d4a18-9fe4-4246-ba44-85cf6b4dace5
  InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
  MachineType: Hewlett-Packard HP Compaq 6710b (GB891ET#ABH)
  PccardctlIdent:
   Socket 0:
     no product info available
  PccardctlStatus:
   Socket 0:
     no card
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-12-generic root=UUID=686d2155-83a9-4743-a2a4-8e9570ee3da6 ro quiet splash vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.0.0-12-generic N/A
   linux-backports-modules-3.0.0-12-generic  N/A
   linux-firmware                            1.60
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 01/15/2009
  dmi.bios.vendor: Hewlett-Packard
  dmi.bios.version: 68DDU Ver. F.15
  dmi.board.name: 30C0
  dmi.board.vendor: Hewlett-Packard
  dmi.board.version: KBC Version 71.2E
  dmi.chassis.asset.tag: CNU72913PH
  dmi.chassis.type: 10
  dmi.chassis.vendor: Hewlett-Packard
  dmi.modalias: dmi:bvnHewlett-Packard:bvr68DDUVer.F.15:bd01/15/2009:svnHewlett-Packard:pnHPCompaq6710b(GB891ET#ABH):pvrF.15:rvnHewlett-Packard:rn30C0:rvrKBCVersion71.2E:cvnHewlett-Packard:ct10:cvr:
  dmi.product.name: HP Compaq 6710b (GB891ET#ABH)
  dmi.product.version: F.15
  dmi.sys.vendor: Hewlett-Packard

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