kernel-packages team mailing list archive

[Rasmus Larsen <rla@xxxxxxxxxx>]

I had this issue too on AWS.

In my case, it was the udev rule for vm-hotadd and the fix as mentioned
previously basically came down to "touch /etc/udev/rules.d/40-vm-
hotadd.rules" which effectively disables the /lib/udev/rules.d/40-vm-
hotadd.rules file (after a reboot).

The udev rule basically seems to only be active for Xen or Hyper-V and
while it seems the Hyper-V stuff was also present in previous versions,
the Xen stuff seems to be introduced in 15.10 or newer.

So if you're seeing this issue on anything running on Xen, including
AWS, try:

touch /etc/udev/rules.d/40-vm-hotadd.rules
reboot

This is probably a bug in Xen or a bug in the kernel.

-- 
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/1518457

Title:
  kswapd0 100% CPU usage

Status in Linux:
  Unknown
Status in linux package in Ubuntu:
  Confirmed

Bug description:
  As per bug 721896 and various others:

  I'm on an AWS t2.micro instance (Xeon E5-2670, 991MiB of memory).
  Occasionally (about once a day), kswapd0 falls into a busy loop and
  spins on 100% CPU usage indefinitely. This can be provoked by
  copying/writing large files (e.g. dding a 256MB file), but it happens
  occasionally otherwise. System memory usage (not including
  buffers/caches) currently sits at 36%, which is typical[1]. Initially
  I had no swap space configured; I've since tried enabling a 256MB swap
  file, but the problem continues to occur and no swap space is used.
  The system can be recovered with `echo 1 > /proc/sys/vm/drop_caches`.

  Happy to provide further information/take further debugging actions.

  
  [1] Full output from `free`:
               total       used       free     shared    buffers     cached
  Mem:       1014936     483448     531488      28556       9756     112700
  -/+ buffers/cache:     360992     653944
  Swap:       262140          0     262140

  ProblemType: Bug
  DistroRelease: Ubuntu 15.10
  Package: linux-image-4.2.0-18-generic 4.2.0-18.22
  ProcVersionSignature: Ubuntu 4.2.0-18.22-generic 4.2.3
  Uname: Linux 4.2.0-18-generic x86_64
  AlsaDevices:
   total 0
   crw-rw---- 1 root audio 116,  1 Nov 19 19:40 seq
   crw-rw---- 1 root audio 116, 33 Nov 19 19:40 timer
  AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
  ApportVersion: 2.19.1-0ubuntu5
  Architecture: amd64
  ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
  AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
  CRDA: N/A
  Date: Fri Nov 20 20:44:30 2015
  Ec2AMI: ami-1c552a76
  Ec2AMIManifest: (unknown)
  Ec2AvailabilityZone: us-east-1d
  Ec2InstanceType: t2.micro
  Ec2Kernel: unavailable
  Ec2Ramdisk: unavailable
  IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig'
  Lsusb: Error: command ['lsusb'] failed with exit code 1: unable to initialize libusb: -99
  MachineType: Xen HVM domU
  PciMultimedia:
   
  ProcEnviron:
   TERM=screen
   PATH=(custom, no user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 xen
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-18-generic root=UUID=35bc01f4-4602-4823-976e-508edef899df ro console=tty1 console=ttyS0 net.ifnames=0
  RelatedPackageVersions:
   linux-restricted-modules-4.2.0-18-generic N/A
   linux-backports-modules-4.2.0-18-generic  N/A
   linux-firmware                            N/A
  RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
  SourcePackage: linux
  UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 05/06/2015
  dmi.bios.vendor: Xen
  dmi.bios.version: 4.2.amazon
  dmi.chassis.type: 1
  dmi.chassis.vendor: Xen
  dmi.modalias: dmi:bvnXen:bvr4.2.amazon:bd05/06/2015:svnXen:pnHVMdomU:pvr4.2.amazon:cvnXen:ct1:cvr:
  dmi.product.name: HVM domU
  dmi.product.version: 4.2.amazon
  dmi.sys.vendor: Xen

To manage notifications about this bug go to:
https://bugs.launchpad.net/linux/+bug/1518457/+subscriptions