Vidar Hoel, it appears you may be hitting multiple bugs simultaneously. Given the call trace no longer appears, it would either be the latest mainline kernel fixes this one issue, or doesn't manifests the bug anymore. I'll mark this Confirmed given that the originally scoped issue isn't resolved.
** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- 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/1652644 Title: Switching users in Ubuntu/Ubuntu Gnome freezes graphics Status in linux package in Ubuntu: Confirmed Bug description: This bug was present in Ubuntu Gnome 16.04 LTS with GDM, but did a clean install of Ubutnu 16.04 LTS with Unity and LightDM, and the bug is still present. How to reproduce: 1. Boot the system, wait for LightDM to start and show the Ubuntu Unity greeter. 2. Log in as a user. 3. From the power menu (top right), choose an other user 4. In the password-promt (greeter) for the user, type in the correct password At this point, one of three thing might happen: a- The desktop, desktop icons, Unity-launcher and main menu for the user is loaded. The user can use the system as expected! b- The desktop, desktop icons and Unity-launcher the user is loaded. However, just before the main-menu-bar at the tops loads, the the graphics freezes. I can move the cursor, but that's it. It is not possible to click or do anything with the mouse-cursor. c- Same as (b), but during this process the screen goes complete blank (black), with only the cursor showing (and moving). When (b) or (c), pressing ALT+F1-F6 does not help, the screen just stays the same (except the cursor dispersers). Pressing ALT+F7 afterwards does not bring the cursor back. The system has not frozen. I can SSH to the box and it lives as nothing has happened. It's only effecting the display/graphics. This bug happens about 1/3 of the times I switch the user. Sometimes I can switch to and from users several times (2-5) before this bug comes to life. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-57-generic 4.4.0-57.78 ProcVersionSignature: Ubuntu 4.4.0-57.78-generic 4.4.35 Uname: Linux 4.4.0-57-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.4 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: sitron 1903 F.... pulseaudio Date: Mon Dec 26 16:58:42 2016 HibernationDevice: RESUME=UUID=9d82d48a-107c-4d15-844d-c4ba62a3d320 InstallationDate: Installed on 2016-12-18 (8 days ago) InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719) IwConfig: lo no wireless extensions. eno1 no wireless extensions. Lsusb: Bus 002 Device 003: ID 046d:c52b Logitech, Inc. Unifying Receiver Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-57-generic root=UUID=2a82deba-0eba-4358-b17c-65be40fe066f ro quiet splash vt.handoff=7 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-4.4.0-57-generic N/A linux-backports-modules-4.4.0-57-generic N/A linux-firmware 1.157.6 RfKill: SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/21/2016 dmi.bios.vendor: Intel Corp. dmi.bios.version: GKPPT10H.86A.0060.2016.1021.1324 dmi.board.name: DCP847SKE dmi.board.vendor: Intel Corporation dmi.board.version: G80890-105 dmi.chassis.type: 3 dmi.modalias: dmi:bvnIntelCorp.:bvrGKPPT10H.86A.0060.2016.1021.1324:bd10/21/2016:svn:pn:pvr:rvnIntelCorporation:rnDCP847SKE:rvrG80890-105:cvn:ct3:cvr: To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1652644/+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