Display freezes on 2nd+subsequent logins
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Expired
|
Medium
|
Unassigned |
Bug Description
First boot after a fresh install of 16.04 from the 16.04.1 amd64 desktop ISO, with 'download updates' enabled. This is alongside an existing 14.04 installation, which continues to work flawlessly. In particular, this issue cannot be reproduced there. (I've installed the -lts-xenial kernel package there, so it's version 4.4.0.34.24, but NOT the xorg ones.)
The first login on the new system worked fine. After simply logging out and in again, the display freezes just after drawing my user's desktop. (This first time, everything was drawn, but on subsequent attempts the background was black and the top Unity panel was empty.) The mouse cursor is movable, but no button or key presses are recognized.
Eventually, I press Ctrl+Alt+F1. The mouse cursor disappears immediately; the display stays frozen and otherwise unchanged. After another two minutes or so of waiting, I am finally dumped to the virtual tty, which works fine. At this point a couple of kernel stack traces appear in dmesg (see below), with timestamps corresponding to "just now," i.e. when the vty switch finally occurred.
Switching back to the X vty via Alt+F7 brings me back to the still-frozen display, at which point all I can do is Ctrl+Alt+F1 and wait ~2 minutes again. Stopping, then starting the lightdm service brings me back to a working login screen, but logging in just freezes right back again. Finally, rebooting the system allows me to login to a working desktop exactly once -- logging out and in again reproduces this problem reliably.
The full dmesg is attached, but the short version is that stack traces appear in pairs, summarized by the following lines on the first occurrence:
[ 242.116429] WARNING: CPU: 2 PID: 2539 at /build/
[ 242.116498] CPU: 2 PID: 2539 Comm: Xorg Not tainted 4.4.0-31-generic #50-Ubuntu
and by the following, slightly different ones, on the second and beyond:
[ 380.232443] WARNING: CPU: 1 PID: 4173 at /build/
[ 380.232563] CPU: 1 PID: 4173 Comm: Xorg Tainted: G W 4.4.0-31-generic #50-Ubuntu
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-
ProcVersionSign
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
CurrentDesktop: Unity
Date: Fri Aug 12 19:51:28 2016
HibernationDevice: RESUME=
InstallationDate: Installed on 2016-08-13 (0 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
MachineType: LENOVO 4236AR5
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=
RelatedPackageV
linux-
linux-
linux-firmware 1.157.2
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/31/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 83ET66WW (1.36 )
dmi.board.
dmi.board.name: 4236AR5
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.
dmi.modalias: dmi:bvnLENOVO:
dmi.product.name: 4236AR5
dmi.product.
dmi.sys.vendor: LENOVO
tags: | added: kernel-fixed-upstream |
I also took an ubuntu-bug --save of xorg. Trying to update this report with it didn't work (apport-cli -u tells me I must use apport-collect, which has no option to use an existing save file), but it is attached in its raw form.