I suffered from these messages after upgrading to Kubuntu 16.04. After changing my hard drive, then my entire PC, then upgrading the kernel to 4.5.2 and also my nVidia drivers to 364.19, the messages went away.
However, I STILL saw intermittent lockups. These finally went away after I turned off KDE's file indexing (baloo-file-indexer). I suspect that my original NMI problems could have also stemmed from that. I've latched onto bug #1548051 for the file-indexing problem. -- 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/1495696 Title: NMI watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [firefox:2278] Status in linux package in Ubuntu: Triaged Bug description: Full freeze, screen turns off, happened when Youtube video running in background tab in Firefox. Hard reset necessary. Multiple crashes/freezes have occurred updating linux kernel/image from 3.19.0-28 to 3.19.0-29. All of them have happened when Firefox was running playing html5 videos. ProblemType: KernelOops DistroRelease: Ubuntu 15.04 Package: linux-image-3.19.0-29-generic 3.19.0-29.31 ProcVersionSignature: Ubuntu 3.19.0-29.31-generic 3.19.8-ckt6 Uname: Linux 3.19.0-29-generic x86_64 NonfreeKernelModules: nvidia Annotation: Your system might become unstablenow and might need to be restarted. ApportVersion: 2.17.2-0ubuntu1.4 Architecture: amd64 Date: Mon Sep 14 23:21:15 2015 Failure: oops HibernationDevice: RESUME=UUID=e82835fd-236c-4458-b8eb-2815c0d14261 IwConfig: eth0 no wireless extensions. lo no wireless extensions. MachineType: Gigabyte Technology Co., Ltd. GA-970A-UD3 ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-29-generic root=UUID=ebf725f8-53e7-43f5-a8c8-04a43ef1a5d9 ro quiet splash PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: kerneloops-daemon 0.12+git20090217-3ubuntu8 RfKill: SourcePackage: linux Title: NMI watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [firefox:2278] UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev' UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 12/20/2012 dmi.bios.vendor: Award Software International, Inc. dmi.bios.version: F8a dmi.board.name: GA-970A-UD3 dmi.board.vendor: Gigabyte Technology Co., Ltd. dmi.chassis.type: 3 dmi.chassis.vendor: Gigabyte Technology Co., Ltd. dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF8a:bd12/20/2012:svnGigabyteTechnologyCo.,Ltd.:pnGA-970A-UD3:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-970A-UD3:rvr:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr: dmi.product.name: GA-970A-UD3 dmi.sys.vendor: Gigabyte Technology Co., Ltd. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1495696/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp