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: username 4414 F.... pulseaudio
username 4778 F.... pulseaudio
/dev/snd/controlC0: username 4414 F.... pulseaudio
username 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.
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1318116
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.