Ubuntu freezes completely when switching user

Status changed to 'Confirmed' because the bug affects multiple users.

I found a workaround that works fine for my i5 laptop with nvidia optimus card.

Install the latest nvidia drivers and reboot. After that the user switch does work again.

sudo apt-get install nvidia-319 nvidia-settings-319 nvidia-prime

This bug affects me as well. No nvidia card however. Output of lshw for the display portion is as follows:

description: VGA compatible controller
             product: Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller
             vendor: Intel Corporation
             physical id: 2
             bus info: pci@0000:00:02.0
             version: 09
             width: 64 bits
             clock: 33MHz
             capabilities: msi pm vga_controller bus_master cap_list rom
             configuration: driver=i915 latency=0
             resources: irq:44 memory:f7800000-f7bfffff memory:e0000000-efffffff ioport:f000(size=64)

Adam Niedling, thank you for reporting this bug and helping make Ubuntu better. This bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach missing debug information to this report:

apport-collect -p linux <replace-with-bug-number>

If reproducible, could you also please test the latest upstream kernel available (rc3, not rc4 as it doesn't have the all necessary files) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-v3.13-rc3

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

Are you being serious? It was reported 1,5 months ago. Last activity was 16 days ago. Do you want me to test the upstream kernel daily or what?

This bug affect the latest stable version of Ubuntu and it is still a bug.

What makes you think this is a kernel bug anyway? It is not happening if the nVidia card is disabled in the bios.

I am not using any nvidia hardware and I have this exact same issue. I believe the bug is within lightdm.

Rob Tongue, the computer freezing would indicate either an x crash, or kernel call trace, which are both treated under separate reports based on differing hardware. Hence, so your hardware may be tracked, could you please file a new report by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Rob, don't listen to him. I got into an argument with him at bug #131094 and now he's here on a personal vendetta. He's just gonna keep asking for irrelevant information until it gets so difficult to answer that he can close this bug.

Christopher, I don't recognize your authority, leave this bug report alone!
Until someone from Canonical confirms that your activities are valid I don't want you to touch this bug report!

Adam Niedling, thank you for your comments. Regarding https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1247189/comments/7 :
"Are you being serious? It was reported 1,5 months ago. Last activity was 16 days ago. Do you want me to test the upstream kernel daily or what?"

When it was reported, and last activity are not relevant data points here. I would like you to test the daily release and perform the apport-collect as previously requested in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1247189/comments/6 so that your hardware information may be gathered.

"This bug affect the latest stable version of Ubuntu and it is still a bug."

Just to clarify, which one specifically?

"What makes you think this is a kernel bug anyway?"

As you noted, your Ubuntu freezes completely, which would indicate either an xorg crash, or kernel call trace. This has yet to be determined.

" It is not happening if the nVidia card is disabled in the bios."

Thank you for that data point.

Regarding your comments https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1247189/comments/10 :
"I got into an argument with him at bug #131094 and now he's here on a personal vendetta. He's just gonna keep asking for irrelevant information until it gets so difficult to answer that he can close this bug."

To maintain a respectful atmosphere, please follow the code of conduct - http://www.ubuntu.com/project/about-ubuntu/conduct . Bug reports are handled by humans, the majority of whom are volunteers, so please bear this in mind.

With that noted, please stop with your baseless accusations, and personal attacks as it's just simply rude, and distracts from getting bugs resolved. I frankly have better things to do with my time then be on a personal vandetta. The information is being asked for so that this report may move forward, and Rob may get his bug fixed. If you want your report to stall and not be fixed, then continuing to not provide requested information well within your abilities to do, and be rude to people, would do this.

Thank you for your understanding.

Helpful bug reporting tips:
https://help.ubuntu.com/community/ReportingBugs

Christopher, before I attach all of that, I want to note, that I enabled prerelease updates on my system, and it pulled in a new version of kernel, lightdm, and xorg. I have not had the issue happen since then, so I am going to assume that this bug was fixed upstream. If it happens again, I will update this bug with more detail.

Nevermind, I just had it happen again. This is really frustrating, but apport noticed it as a crash within Xorg. I will provide additional info and attach it to THIS bug report. (why create another one?????)

Here is Xorg log file which contains an error.

It is not restricted to nvidia devices.

OK, so this bug is now a security issue, seeing as I just typed my system password in an IRC chat window. When this bug just happened to me, I dropped to TTY1, logged in, did sudo service lightdm restart, typed password again, and when I got back into my session, it turns out since I had quassel foregrounded it ALSO put my username and passwords there. THIS BUG NEEDS TO BE FIXED NOW!!!!!

Christopher, please stop sending me private emails asking me to file a separate bug, especially when you say things like:

"I'm personally not inclined to respond to non-original reporters of a
given bug report, despite them insisting on it's a duplicate, as they
tend not to respect how it's making it harder to triage the report."

WHAT????? So what is the point of "Bug Heat", and why would I start that counter over on a new bug report? I'm sorry, that makes no sense to me.

Also, I have checked some activity on other bugs you have commented on, with the same canned answers. Triage all the bugs you want, but stop turning the triage into a nightmare for the bug reporter, to the point where they give up and close the bug out of sheer aggravation from YOU. Have you even read the Code of Conduct that you keep linking to?

With that said. Let me quote the original bug report:

"I'm using a freshly installed Ubuntu 13.10. As soon as I click on a different user I want to switch to in the gearbox menu I get a black screen and nothing else is happening. I'm still able to SSH to that box and top does not show any process taking 100% CPU. Alt+sysrq+b is able to reboot the system. I had no problem like this with Ubuntu 13.04 on the same computer."

THAT IS THE EXACT SAME THING HAPPENING TO ME. I will NOT file another bug on this, as this one is perfectly fine. I will, however, install Ubuntu on several different machines that I have laying around, just to see if it happens on multiple hardware types, and even in virtual machines.

Status changed to 'Confirmed' because the bug affects multiple users.

I am experiencing this issue since I upgraded to 13.10 from 13.04.
No nVidia card but Intel:
Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09)

The system does not hang. From my experience it just get stuck trying to open a new VT.
It fails to switch to the Greeter and a black screen is shown, but you can go back to your previous VT (CTRL-ALT-F7) or to a new one (e.g. tty1).

Versions:
lightdm 1.8.4-0ubuntu1 amd64
kernel 3.11.0-14-generic
All packages up-to-date as of 20131228.1000-UTC

WORKAROUND:
The problem solved after updating lightdm to version 1.8.5-0ubuntu1, available in saucy-proposed repository.

After the lightdm upgrade I experience some performance issues related to plugin xfce4-xkb-plugin when switching between users. Seem to be resolved removing the plugin from all panels.

Dear all.

I have the same problem after upgrading from 13.04. Only now I use ubuntu 13.10 GNOME running GDM.

[Although I had the same problem when I tried unity with lightdm - History: I was so frustrated I tried Unity (32 & 64 bit) and now Gnome all with the same results.]

Ubuntu Gnome 13.10 32-bit.
NVIDIA Corporation GT218M (NVS 3100M/PCIe/SSE2)
3.8.0-34-generic
GDM 3.8.4

I switch user. I have the new user session. I then alt-ctl-f7. I then have a frozen background-artwork-only graphic screen for the 1st user session. No alt-ctl-f1,2,3,4,5,6,7 and so on. I have not yet tested if I am able to ssh into the machine after it hangs.

Please advise of any additional info or tasks needed. I am currently away on leave but shall be able to attend to instructions from you re this matter from 2nd last week Jan'14 onward.

This really affects me allot as I have seperate business and home user id's and switched allot in 13.04.

Kind regards,
Justin

Justin Solms, thank you for your comment. So your hardware may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug xorg

For more on this, please read the official Ubuntu documentation:
X.Org Team, Ubuntu Bug Control, and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://help.ubuntu.com/community/ReportingBugs

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Still an issue in today's release of Trusty and upstream kernel 3.13-rc7.

BTW: apport-collect gives the following error message: dpkg-query: no packages found matching linux

Adam Niedling, thank you for providing the requested information. As per your https://launchpadlibrarian.net/161645392/CurrentDmesg.txt :
[ 6.254915] [drm] Wrong MCH_SSKPD value: 0x16040307
[ 6.254918] [drm] This can cause pipe underruns and display issues.
[ 6.254919] [drm] Please upgrade your BIOS to fix this

Given you are running currently running the latest BIOS available for your model, it would be helpful if you engaged Acer via your SNID to inquire about an updated BIOS being made available.

However, let this not be a show stopper in in finding a WORKAROUND without having to disable the nvidia card.

Given no call trace was found in your dmesg, could you please capture the xorg back trace following https://help.ubuntu.com/community/DebuggingSystemCrash ?

And what exactly do you want me to tell Acer? I have no idea what MCH_SSKPD means...

There are no exact steps about capturing a xorg backtrace at https://help.ubuntu.com/community/DebuggingSystemCrash. It's just general information. Please direct me to somewhere with exact steps to follow.

Are you trying to blame this bug on the Bios? Then why didn't I have this problem prior to 13.10?

Requested information is not clear and/or might be misleading. There was nothing wrong with my hardware before 13.10.

Maarten, This actually makes lots of sense. I had it happen again last night, and after checking logs, it was indeed Xorg losing control of direct rendering. I can move the mouse around the black screen, and watch the cursor change as it goes over links, and various other things, and I can still type in whatever window was active.... I just can't see any of it. Even dropping to TTY1, the mouse cursor is still visible, and keystrokes still get dumped to the active window, even though I dropped to another tty. Also I am on Intel hardware.

Even though upgrading ligtgdm to 1.8.5-0ubuntu1 seemed to solve the problem I am now experiencing the problem again.

Ubuntu 13.10
Graphics: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09)
xserver-xorg-video-intel 2:2.99.904-0ubuntu2.1
linux 3.11.0-15-generic

I have discovered a side effect to this bug that implies a security vulnerability.

You are in graphical tty7 and select the "switch user" option.
The xserver gets stuck trying to open a new graphical tty. You have black screen on tty8. You cannot go back to tty7.

Still you can open a non-graphical tty (tty1-tty6).
You have to login on the new tty, so you write username and password.

But all keyboard activity is still being captured on original tty7!!
You are exposing your login and password credentials (at least) to the foreground application on tty7.

Hi people,

With is, I've solved the problem. But I need to do it from time to time (up to now, I've done it twice)

Thanks

http://askubuntu.com/a/382826/248021

Hi People,
Iḿ using 14.04 and experienced this bug on first try to switch users.

FRESH install of 14.04.
My user as computer admin, my wife as normal user, another 3 users (nerver logged in)

steps:
1. Boot
2 . Logged in with first user
3. Upper rigth "gear" icon -> sithch user
4. Desktop shows screen with all users, but frezzes completely

-> not able to ctrl-alt-Fn to any tty
-> If previosly openned a TTY not able to switch back

The only UI custom sets where enable local menus , language settings portuguese,, enable directory sort on nautilus and set wallpaper.

===== SETUP PACKAGES ==========
After fresh install:
sudo apt-get update && sudo apt-get upgrade
sudo apt-get install geany geany-plugins vim zim nmon
--
sudo apt-get install gimp gimp-data gimp-data-extras gimp-plugin-registry graphviz gnuplot feedgnuplot gnuplot-doc libgnuplot-iostream-dev python-gnuplot graphviz-doc icu-doc
fontforge fontforge-extras icontool imagemagick inkscape
sudo apt-get install vlc zim unity-tweak-tool mplayer smplayer
sudoo apt-get install gstreamer0.10-plugins-ugly libxine1-ffmpeg gxine mencoder libdvdread4 totem-mozilla icedax tagtool easytag id3tool lame nautilus-script-audio-convert libmad0 mpg321 libavcodec-extra
l ubuntu-restricted-extras
sudo /usr/share/doc/libdvdread4/install-css.sh
----
sudo apt-get install clamav clamtk
--
#### Java
sudo apt-get install openjdk-7-jdk openjdk-7-jre icedtea-7-plugin
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer
sudo apt-get install oracle-java7-installer
sudo apt-get install oracle-java6-installer
---
sudo apt-get install skype
sudo apt-get install filezilla filezilla-common
sudo apt-get install unace rar unrar p7zip-rar p7zip zip unzip sharutils uudeview mpack arj cabextract file-roller
---
sudo apt-get install darktable digikam

#### Chrome
wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
sudo sh -c 'echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'
sudo apt-get update
sudo apt-get install google-chrome-stable
----
sudo apt-get install activity-log-manager activity-log-manager-control-center
sudo apt-get install gufw
--
#### NETFLIX
sudo apt-add-repository ppa:ehoover/compholio;
sudo apt-get update ;
sudo apt-get install netflix-desktop redbox-desktop lovefilm-desktop;
--
#### Virtualbox
sudo sh -c 'echo "deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -sc) contrib" >> /etc/apt/sources.list'
sudo sh -c 'echo "deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -sc) contrib" >> /etc/apt/sources.list'
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
sudo apt-get update & sudo apt-get install virtualbox
---
sudo apt-get install flashplugin-installer
sudo apt-get install nmon
sudo apt-get install unity-tweak-tool
sudo apt-get install gnome-tweak-tool
--
#### Dropbox
sudo apt-get install nautilus-dropbox
sudo apt-get install libappindicator1
---
#### Pipelight
sudo apt-add-repository ppa:pipelight/stable
sudo apt-get update
sudo apt-get install pipelight-multi
sudo pi...

This has been fixed in 14.04 for me.

Hmm, I'm still seeing this with an apparently up to date 14.04. It's an Acer Aspire 1301 which until I installed 14.04 (fresh on SSD) was working fine. What I have noticed is that I can now only use the Nouveau drivers - the Nvidia ones are hopeless - crashes with major rendering issues almost straight away. Again, all was fine prior to 14.04.

The death is infrequent - can use for a couple of days over multiple simultaneous logins, then get a lock when switching users. alt-ctrl-f1 drops me back to a terminal, alt-ctrl-f7 back to the frozen display. So next time it happens, what is the best way of capturing a log?

JamesH, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report by executing the following in a terminal:
ubuntu-bug xorg

Please ensure you have xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

For more on this, please see the official Ubuntu documentation:
Ubuntu X.Org Team, Ubuntu Bug Control, and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report will delay your problem being addressed as quickly as possible.

Thank you for your understanding.

I'm using a freshly installed Ubuntu 14.04 with kernel 3.13.0-24 and 3.13.0-29. As soon as I click on a different user I want to switch to in the gearbox menu I get a black screen and nothing else is happening. I'm still able to SSH to that box and top does not show any process taking 100% CPU. Alt+sysrq+b is able to reboot the system as is sudo shutdown now -h

Tried different versions of the nVidia Driver including 331, 319, 310 and 304. This is an HP zBook with nVidia Quadro K3000M plus an embedded Intel. With Hybrid graphics switched off (nVidia GPU only), this problem occurs. With Hybrid Graphics switched on or auto, (Intel GPU active), the GUI does not even start.

Also, same outcome if I lock the terminal and instead of unlocking I choose switch user.

Only way to switch user is to log out then log in as new user which is not always the best thing under the circumstances of this particular situation.

Karim Hosein, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report by executing the following in a terminal:
ubuntu-bug xorg

Please ensure you have xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

For more on this, please see the official Ubuntu documentation:
Ubuntu X.Org Team, Ubuntu Bug Control, and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report will delay your problem being addressed as quickly as possible.

Thank you for your understanding.

Hi,
I have exactly the same problem with 14.04, with 16.04 it doens't freeze but I have just the icon (and not all) in the windows, without the text below it.

L'Africain, it will help immensely if you filed a new report with Ubuntu by ensuring you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information running the following from a terminal:
ubuntu-bug xorg

Also, please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

ok I sent the xdiagnose bug report.

I'm sorry I forgot the link : https://bugs.launchpad.net/ubuntu/+source/xorg/+filebug/040575ce-6f5b-11e6-a147-d485646cd9a4