Oh, and maybe of less relevance, but to keep it complete, here is the
output of "top":
top - 13:46:47 up 5 days, 56 min, 2 users, load average: 1.00, 0.97, 1.01
Tasks: 172 total, 2 running, 170 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.0 us, 12.0 sy, 0.0 ni, 83.3 id, 0.0 wa, 4.8 hi, 0.0 si, 0.0 st
KiB Mem: 16415556 total, 2105640 used, 14309916 free, 390756 buffers
KiB Swap: 4194296 total, 0 used, 4194296 free. 865744 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
86 root 20 0 0 0 0 R 100.0 0.0 6867:11 kworker/2:1
15637 root 20 0 24956 1760 1172 R 0.3 0.0 0:00.03 top
...
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https://bugs.launchpad.net/bugs/1322407
Title:
NFS kernel server creates a kworker with 100% CPU usage, then hangs
randomly
Status in “linux” package in Ubuntu:
Confirmed
Bug description:
This concerns the server edition of 14.04. I have set up a NFS server.
Once I attach at least one client, one kworker process starts to use
100% CPU. The runaway kworker returns to idle when I reset the NFS
server daemon with "service nfs-kernel-server stop" followed by
"service nfs-kernel-server start". With the nfs kernel server stopped,
the CPU remains idle. With the nfs kernel server running, as soon as
one client requests a connection, the kworker process jumps to 100%
CPU again.
After some random time, the nfs kernel server no longer accepts
requests from clients. Restarting the service allows clients to
reconnect. The syslog shows no relevant information.
This problem has never appeared on a very similar server setup with
12.04.
Configration: The svcgssd is not running. I played with various
configurations (enabling/disabling NFSv3 and NFSv4), but it makes no
difference.
I tried to enable event debugging:
#> echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event
#> cat /sys/kernel/debug/tracing/trace_pipe > /var/tmp/kerntrace.txt
and found the following kernel trace in a tight loop:
[...]
kworker/2:1-86 [002] d... 161940.910668: workqueue_queue_work: work
struct=ffff8804140675e0 function=xs_tcp_setup_socket [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d.s. 161940.910674: workqueue_queue_work: work
struct=ffff8800cef9f488 function=rpc_async_schedule [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d... 161940.910675: workqueue_queue_work: work
struct=ffff8804140675e0 function=xs_tcp_setup_socket [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d.s. 161940.910681: workqueue_queue_work: work
struct=ffff8800cef9f488 function=rpc_async_schedule [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d... 161940.910682: workqueue_queue_work: work
struct=ffff8804140675e0 function=xs_tcp_setup_socket [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d.s. 161940.910688: workqueue_queue_work: work
struct=ffff8800cef9f488 function=rpc_async_schedule [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d... 161940.910689: workqueue_queue_work: work
struct=ffff8804140675e0 function=xs_tcp_setup_socket [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d.s. 161940.910695: workqueue_queue_work: work
struct=ffff8800cef9f488 function=rpc_async_schedule [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d... 161940.910696: workqueue_queue_work: work
struct=ffff8804140675e0 function=xs_tcp_setup_socket [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
kworker/2:1-86 [002] d.s. 161940.910702: workqueue_queue_work: work
struct=ffff8800cef9f488 function=rpc_async_schedule [sunrpc]
workqueue=ffff8800cfbb6a00 req_cpu=256 cpu=2
[...]
At present, I have to consider NFS fubar.
Thanks,
Mark
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-24-generic 3.13.0-24.47
ProcVersionSignature: Ubuntu 3.13.0-24.47-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version
k3.13.0-24-generic.
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.14.1-0ubuntu3.1
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path',
'/dev/snd/controlC0', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D0c',
'/dev/snd/pcmC0D0p', '/dev/snd/pcmC0D1p', '/dev/snd/pcmC0D2c', '/dev/snd/seq',
'/dev/snd/timer'] failed with exit code 1:
CRDA: Error: [Errno 2] No such file or directory: 'iw'
Card0.Amixer.info: Error: [Errno 2] No such file or directory: 'amixer'
Card0.Amixer.values: Error: [Errno 2] No such file or directory: 'amixer'
Date: Thu May 22 22:48:48 2014
HibernationDevice: RESUME=UUID=adcdeef5-9b46-4ea4-b9f4-b6e642ea91e8
InstallationDate: Installed on 2014-05-12 (10 days ago)
InstallationMedia: Ubuntu-Server 14.04 LTS "Trusty Tahr" - Release amd64
(20140416.2)
IwConfig:
eth0 no wireless extensions.
lo no wireless extensions.
MachineType: Gigabyte Technology Co., Ltd. GA-990XA-UD3
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic
root=UUID=6cf411b3-3e8e-41e5-8670-db14ad259f58 ro IOMMU=soft nomdmonddf
nomdmonisw
RelatedPackageVersions:
linux-restricted-modules-3.13.0-24-generic N/A
linux-backports-modules-3.13.0-24-generic N/A
linux-firmware 1.127.2
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
WifiSyslog:
dmi.bios.date: 10/13/2011
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: F9
dmi.board.name: GA-990XA-UD3
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.:bvrF9:bd10/13/2011:svnGigabyteTechnologyCo.,Ltd.:pnGA-990XA-UD3:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-990XA-UD3:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
dmi.product.name: GA-990XA-UD3
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
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