Comment 0 for bug 1655842

I recently replaced some Xenial servers, and started experiencing "Out of memory" problems with the default kernel.

We bake Amazon AMIs based on an official Ubuntu-provided image (ami-e6b58e85, in ap-southeast-2, from https://cloud-images.ubuntu.com/locator/ec2/). Previous versions of our AMI included "4.4.0-57-generic", but the latest version picked up "4.4.0-59-generic" as part of a "dist-upgrade".

Instances booted using the new AMI have been using more memory, and experiencing OOM issues - sometimes during boot, and sometimes a while afterwards. An example from the system log is:

[ 130.113411] cloud-init[1560]: Cloud-init v. 0.7.8 running 'modules:final' at Wed, 11 Jan 2017 22:07:53 +0000. Up 29.28 seconds.
[ 130.124219] cloud-init[1560]: Cloud-init v. 0.7.8 finished at Wed, 11 Jan 2017 22:09:35 +0000. Datasource DataSourceEc2. Up 130.09 seconds
[29871.137128] Out of memory: Kill process 2920 (ruby) score 107 or sacrifice child
[29871.140816] Killed process 2920 (ruby) total-vm:675048kB, anon-rss:51184kB, file-rss:2164kB
[29871.449209] Out of memory: Kill process 3257 (splunkd) score 97 or sacrifice child
[29871.453282] Killed process 3258 (splunkd) total-vm:66272kB, anon-rss:6676kB, file-rss:0kB
[29871.677910] Out of memory: Kill process 2647 (fluentd) score 51 or sacrifice child
[29871.681872] Killed process 2647 (fluentd) total-vm:117944kB, anon-rss:23956kB, file-rss:1356kB

I have a hunch that this may be related to the fix for https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1647400, introduced in linux (4.4.0-58.79).

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-59-generic 4.4.0-59.80
ProcVersionSignature: User Name 4.4.0-59.80-generic 4.4.35
Uname: Linux 4.4.0-59-generic x86_64
AlsaDevices:
 total 0
 crw-rw---- 1 root audio 116, 1 Jan 12 06:29 seq
 crw-rw---- 1 root audio 116, 33 Jan 12 06:29 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.20.1-0ubuntu2.4
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:
Date: Thu Jan 12 06:38:45 2017
Ec2AMI: ami-0f93966c
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: ap-southeast-2a
Ec2InstanceType: t2.nano
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig'
Lsusb: Error: command ['lsusb'] failed with exit code 1:
MachineType: Xen HVM domU
PciMultimedia:

ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 cirrusdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-59-generic root=UUID=fb0fef08-f3c5-40bf-9776-f7ba00fe72be ro console=tty1 console=ttyS0
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-59-generic N/A
 linux-backports-modules-4.4.0-59-generic N/A
 linux-firmware 1.157.6
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/09/2016
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:bd12/09/2016:svnXen:pnHVMdomU:pvr4.2.amazon:cvnXen:ct1:cvr:
dmi.product.name: HVM domU
dmi.product.version: 4.2.amazon
dmi.sys.vendor: Xen