[Toshiba Ultrabook STi UB 1401] kworker process takes up ~95% of one CPU after suspending and resuming

[Pablo Almeida]

On my computer, everytime I suspend and resume, a process appears called kworker and takes around 95% CPU until next reboot. Contrary to what I've seen around, the lid doesn't have to be closed and it doesn't affect the next suspending.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-14-generic 3.11.0-14.21
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: pablo 1565 F.... pulseaudio
Date: Wed Nov 27 22:26:17 2013
InstallationDate: Installed on 2013-11-22 (5 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MachineType: Semp Toshiba Informatica Ltda STI UB 1401
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-14-generic root=UUID=3e3b8395-cedc-465a-938b-6ca56aba7539 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-14-generic N/A
 linux-backports-modules-3.11.0-14-generic N/A
 linux-firmware 1.116
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/29/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 4.6.5
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: STI UB 1401
dmi.board.vendor: Semp Toshiba Informatica Ltda
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 9
dmi.chassis.vendor: Semp Toshiba Informatica Ltda
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd05/29/2012:svnSempToshibaInformaticaLtda:pnSTIUB1401:pvrRev.10/00:rvnSempToshibaInformaticaLtda:rnSTIUB1401:rvrTobefilledbyO.E.M.:cvnSempToshibaInformaticaLtda:ct9:cvrToBeFilledByO.E.M.:
dmi.product.name: STI UB 1401
dmi.product.version: Rev. 10/00
dmi.sys.vendor: Semp Toshiba Informatica Ltda

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Sounds similar to bug 1223851

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.12 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13-rc2-trusty/

[Pablo Almeida (pabloalmeidaff9)]

Hello. Thanks for helping.

I did the test for versions 3.12 and 3.13-rc2. The problem persists in both versions.

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org.

Once this bug is reported upstream, please add the tag: 'kernel-bug-reported-upstream'.

[0] https://wiki.ubuntu.com/Bugs/Upstream/kernel

[Pablo Almeida (pabloalmeidaff9)]

Contrary to what was previously ocurring, this problem started arising now even when the computer has not been suspended. It's getting worse.

[Joseph Salisbury (jsalisbury)]

The 3.13-rc6 kernel is now available, can you see if this kernel also exhibits the bug:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13-rc6-trusty/

[Pablo Almeida (pabloalmeidaff9)]

Hello, Joseph. Just tested it and still no solution.
You can see the problem in action in the screenshot I'm attaching, with the newest kernel.