kernel-packages team mailing list archive

[Mark Haidekker <mhaidekk@xxxxxxxxx>]

Public bug reported:

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.

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug nfs-server trusty

** Description changed:

  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 nable 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
+      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.
+  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
+  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
+  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.

** Description changed:

  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 nable event debugging:
+ 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.

-- 
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/1322407

Title:
  NFS kernel server creates a kworker with 100% CPU usage, then hangs
  randomly

Status in “linux” package in Ubuntu:
  New

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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