Can you also test the latest v3.13 stable kernel to see if the fix in 3.15 already migrated down through stable? It can be downloaded from:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13.11.2-trusty/ ** Changed in: linux (Ubuntu) Status: Confirmed => Triaged -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1318116 Title: kworker uses 100% CPU when nfs-kernel-server is active Status in “linux” package in Ubuntu: Triaged 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: 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. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1318116/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
