Black screen login

Bug #1154065 reported by lesebas on 2013-03-12
This bug affects 12 people
Affects Status Importance Assigned to Milestone
LightDM Webkit Greeter
Scott Balneaves

Bug Description


I’m using lightdm with webkit-greeter on archlinux x86_64 system. Since last update and after installing compiz on my distro I have a black screen with only mouse pointer. If I swap to gtk-greeter it’s working fine. Here are the content of the log files:

[code]This is a pre-release version of the X server from The X.Org Foundation.
It is not supported in any way.
Bugs may be filed in the bugzilla at
Select the "xorg" product for bugs you find in this release.
Before reporting bugs in pre-release versions please check the
latest version in the X.Org Foundation git repository.
See for git access instructions.

X.Org X Server (1.13.3 RC 1)
Release Date: 2013-02-15
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.7.5-1-ARCH x86_64
Current Operating System: Linux Lupus 3.7.10-1-ARCH #1 SMP PREEMPT Thu Feb 28 09:50:17 CET 2013 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-linux root=UUID=efc6b395-f237-44cb-8ee1-2bbe21cab289 ro quiet
Build Date: 18 February 2013 03:52:56PM

Current version of pixman: 0.28.2
   Before reporting problems, check
   to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
   (++) from command line, (!!) notice, (II) informational,
   (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Mar 11 22:51:49 2013
(==) Using config directory: "/etc/X11/xorg.conf.d"
Initializing built-in extension Generic Event Extension
Initializing built-in extension SHAPE
Initializing built-in extension MIT-SHM
Initializing built-in extension XInputExtension
Initializing built-in extension XTEST
Initializing built-in extension BIG-REQUESTS
Initializing built-in extension SYNC
Initializing built-in extension XKEYBOARD
Initializing built-in extension XC-MISC
Initializing built-in extension SECURITY
Initializing built-in extension XINERAMA
Initializing built-in extension XFIXES
Initializing built-in extension RENDER
Initializing built-in extension RANDR
Initializing built-in extension COMPOSITE
Initializing built-in extension DAMAGE
Initializing built-in extension MIT-SCREEN-SAVER
Initializing built-in extension DOUBLE-BUFFER
Initializing built-in extension RECORD
Initializing built-in extension DPMS
Initializing built-in extension X-Resource
Initializing built-in extension XVideo
Initializing built-in extension XVideo-MotionCompensation
Initializing built-in extension XFree86-VidModeExtension
Initializing built-in extension XFree86-DGA
Initializing built-in extension XFree86-DRI
Initializing built-in extension DRI2
Loading extension GLX
Loading extension NV-GLX
Loading extension NV-CONTROL
Loading extension XINERAMA
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning: Type "ONE_LEVEL" has 1 levels, but <RALT> has 2 symbols
> Ignoring extra symbols
Errors from xkbcomp are not fatal to the X server
Server terminated successfully (0). Closing log file. [/code]

[code] ** (process:1102): WARNING **: Failed to open CK session: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ConsoleKit was not provided by any .service files

(lightdm-webkit-greeter:1104): GLib-GObject-WARNING **: gsignal.c:2459: signal `show-error' is invalid for instance `0x23ad8c0'

(lightdm-webkit-greeter:1104): GLib-GObject-WARNING **: gsignal.c:2459: signal `timed-login' is invalid for instance `0x23ad8c0'

(lightdm-webkit-greeter:1104): GLib-GObject-WARNING **: gsignal.c:2459: signal `quit' is invalid for instance `0x23ad8c0'[/code]

Related branches

Fighter19 (littlefighter1996) wrote :

I can approve this, same problem here on Archlinux x86_64

Prem Anand (h.prem.anand) wrote :

I am also seeing the same issue with ubuntu 13.04

Prem Anand (h.prem.anand) wrote :

I was able to debug this further and found that lightdm-webkit-greeter is in somekind of deadlock. I have collected the backtrace of all the threads. Can someone have a look and figure out the reason for this deadlock

gentunian (sebastian-treu) wrote :

Same here. I noted that black screen is displayed the second time lightdm runs.

After downloading, configuring, making and installing lightdm-webkit-greeter I started the service and I could see the greeter showing that couldn't load theme. That was because theme path was wrong. I fixed the path, restarted the service and I got a black screen every time. I thought it was configuration issue, I try everyting until I decided to reboot to see why I was able to get it to work just once.

After reboot, the greeter appeared. I switch to a terminal, restarted the service, and then the black screen appeared again.

I've checked the log, I googled 'lightdm failed to open CK seesion' and I landed here.

Fedora 19, x86_64, installed version lightdm-webkit-greeter-0.1.2.

gentunian (sebastian-treu) wrote :

*correction* "I noted that black screen is displayed the second time lightdm runs." I meant that it only works the first time it runs.

Jan-Philipp Litza (jplitza) wrote :

This backtrace has a bit more debugging symbols in it.

The problem is: Thread 1 initializes the iBus (ibus_im_context_new()) and thus locks GLib's class_init_rec_mutex. It then continues to read the ibus config and therefore wants to initialize GVfs, where it runs into GIO's already locked default_modules_lock, because...

Thread 2 first arrives at opening a file, wants to initialize GVfs and thus locks the default_modules_lock but then waits for the class_init_rec_mutex to initialize the GLocalVfs.

Jan-Philipp Litza (jplitza) wrote :

Now a really crappy but seemingly working workaround is to once open a file (f.e. /dev/null) with g_file_new_for_path() before entering webkit_web_view_load_uri in lightdm-webkit-greeter.c. This is a WORKAROUND, not a SOLUTION! (marking it as patch nonetheless)

no longer affects: ubuntu
lesebas (sebdeligny) wrote :

Yes same thing for me on archlinux, after several months I had forgiven webkit-gtk-greeter. Just freshly re-installed and it works fine...

I'm on Ubuntu 13.10 with lightdm 1.8.5 and lightdm-webkit-greeter 0.1.2 and it's still black screen on second+ lightdm launch

Pierre Beaucamp (pierreb) wrote :

I can confirm the bug on Ubuntu Saucy, lightdm 1.8.6 and lightdm-webkit-greeter 0.1.2.

Wayne (wayne-zhang) wrote :

Same for me on Ubuntu 14.04 X86

Very same issue for me in Antergos (an Arch Linux derivative) except for that the greeter starts blacking out after I install 'ibus-kkc' (iBus Japanese Kana Kanji Input). When I remove 'ibus-kkc', the greeter appears again. When the greeter 'disappears', I only see the mouse over a black background. I take it the theme isn't loading properly?

I have my logs here:

LightDM with iBus-KKC installed:
LightDM without iBus-KKC installed:

 Please let me know if you would use any other logs!

wbx (k-mail-n) wrote :

Same issue on 14.04.3 with amd64.
The workaround fixes the issue for me.

Why we can't add this workaround until the real problem is fixed?

Cost me more than a day to get this working in a stable manner.


Scott Balneaves (sbalneav) wrote :

I don't have a particular problem with this fix. Opening /dev/null isn't a big deal, and if it fixes this bug, it's a small price to pay. I'll apply the fix with some mods, mark it in the code that this should be fixed properly at some point.

Scott Balneaves (sbalneav) wrote :

Fix pushed in rev 25

Changed in lightdm-webkit-greeter:
assignee: nobody → Scott Balneaves (sbalneav)
status: New → Fix Committed
Scott Balneaves (sbalneav) wrote :

Fix released in 1.0

Changed in lightdm-webkit-greeter:
status: Fix Committed → Fix Released
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