After upgrading from stock Ubuntu 14.04 to 16.04 my laptop consistently freezes up and is unresponsive to keyboard or mouse. The only way is to do a hard shutdown. I'm usually in a browser when this happens, and often watching a video or two. It seems to happen more often in Google Chrome than Firefox, but it happens with both. It has happened at least once with no videos loaded. I haven’t observed it freeze / hang when I’m not in a browser, but that's mainly what i use my laptop for.
This issue is correlated to documented Intel CPU errata noted in:
https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/pentium-n3520-j2850-celeron-n2920-n2820-n2815-n2806-j1850-j1750-spec-update.pdf
Call trace:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1575467/+attachment/4648682/+files/kern.log.2.gz
WORKAROUND: Use out-of-tree patch from https://bugzilla.kernel.org/show_bug.cgi?id=109051 . Patch file:
https://bugzilla.kernel.org/attachment.cgi?id=247621
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ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: andrew 1949 F.... pulseaudio
DistroRelease: Ubuntu 16.04
HibernationDevice: RESUME=UUID=e8aaee7c-d956-4519-94f0-cf7aad745020
InstallationDate: Installed on 2015-08-08 (263 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
MachineType: Dell Inc. Inspiron 3451
Package: linux (not installed)
ProcEnviron:
LANGUAGE=en_US
TERM=xterm-256color
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic.efi.signed root=UUID=d01f07be-c906-4024-8eef-a58ba3935298 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
PulseList:
Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-4.4.0-21-generic N/A
linux-backports-modules-4.4.0-21-generic N/A
linux-firmware 1.157
Tags: xenial
Uname: Linux 4.4.0-21-generic x86_64
UpgradeStatus: Upgraded to xenial on 2016-04-22 (4 days ago)
UserGroups:
_MarkForUpload: True
dmi.bios.date: 12/05/2014
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A00
dmi.board.name: 0H4MK6
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: Not Specified
dmi.modalias: dmi:bvnDellInc.:bvrA00:bd12/05/2014:svnDellInc.:pnInspiron3451:pvrA00:rvnDellInc.:rn0H4MK6:rvrA00:cvnDellInc.:ct8:cvrNotSpecified:
dmi.product.name: Inspiron 3451
dmi.product.version: A00
dmi.sys.vendor: Dell Inc.
seems locks are more likely to be a kernel/driver issue than a desktop ui one