[Lucid] New bug: Plasma crash at KDE logout

I can confirm that. It also happenens when rebooting.

I was going to report this bug today but since its already reported i can just say that it happens to me to! Unfortunately there no way to get a backtrace since as soon as i start loading the backtrace the laptop shuts down/reboots

By any chance do you have the wallpaper clock installed? ( version 0.4 )

I think this bug has something to do with the Battery widget. With the Battery widget loaded in the System Tray, quitting plasma-desktop like so:

$ kquitapp plasma-desktop

would make plasma-desktop crash. Attached is the backtrace (I currently don't have the debug packages installed).
Even though the debug information is missing, one can guess that plasma_applet_battery.so may have something to do with the crash.

To test this hypothesis, I removed all instances of the Battery widget and terminated plasma-desktop like before. plasma-desktop terminated cleanly, without any segfaults.

I also tried several other tests, placing the Battery widget in the System Tray, Panel, and on the "desktop" itself. In all tests, plasma-desktop crashed when terminated.

Can anybody else confirm my findings?

I can confirm. Removing the battery-applet completely removes the crash. Dring the removal on the applet plasma-desktop crashed. I can add that a backtrace taken when plasma-desktop crashed during logout gives the same result yours Darwin.

The crash is caused by kubuntu_101_brightness_fn_keys_and_osd.diff.
The attached patch fixes this.

This bug was fixed in the package kdebase-workspace - 4:4.4.2-0ubuntu14

---------------
kdebase-workspace (4:4.4.2-0ubuntu14) lucid; urgency=low

  * Update kubuntu_101_brightness_fn_keys_and_osd.diff from Felix Geyer,
    closes LP: #564433 'Plasma crash at KDE logout'
 -- Jonathan Riddell <email address hidden> Fri, 23 Apr 2010 13:17:36 +0200

I have still the same problem when logging out of KDE.
I'm not able to create a bug report because the shutdown progress is going on and the plasma workspace bug window disappears, but it still writes something regarding (kdeinit4).
I would appreciate any suggestions.

I you press CTRL-AL-F1 you can get to a text-mode console. There you can
attach gdb to kdeinit4 like this

$ gdb kdeinit4 $(pidof kdeinit4)

then gdb will be attached to the runnin kdeinit4. Now press ALT-F7 to get back
into KDE. When the crash occours press CTRL-ALT-F1 again and you will see that
gdb has catched to crash.

Thank you for your answer!
I don't know if i did right, because this is new to me, but I was able to get some (hopefully helpful) information about the crash now.
I attached the file. Please tell me if I was wrong and if you got some instructions for me.

It's ok, but I really do not know how to interpret the dump.
btw. did you issue "thread apply all bt" ? it seems like 2 threads are not
enough.

Sorry, but I'm not sure what you are actually talking about.
I tried to follow your instructions, so i started gnu debugger via "gdb kdeinit4 $(pidof kdeinit4)" and then i went back to logout from my kde session. When the error occured, I switchted back to tty1, but there was no further information in gdm.
Thats why I'm not able to tell you if there was a "thread apply all bt" or something like that.

No problem

When at the prompt seeing the crash type the following two lines

set logging file crashdump.txt
thread apply all bt

It should put a more complete backtrace in the file crashdump.txt

Ok, I tried to get something, but I'm still not sure if I did it the right way.
When logging out of KDE, the KDE crash box appears and disappears.
After that the workspace is stuck until I quit gdm, so I switch via ctrl+alt+f1 to tty1 but nothing appended in gdm. Then I wrote:

set logging on
thread apply all bt

The result can be seen in gdb.txt.

It's not much information, but you may find anything.
If I'm still wrong please don't give up :]

Ehm .... still not enough output.

Remember that when the crash happenens you should switch immediately to tty1.

I'm going back immediately. The problem is: there is no output coming at the console.
The only output comes, when I write "thread apply all bt". This output looks always similar to the given gdb.txt.

Do I need to install some more debug symbols or anything?
Any instructions in gdb ...?

Try installing kdebase-dbg

Sorry, did not change anything unfortunately.
The KDE error box is not appearing every time I log off, so I try to get this error reproducible.
I will tell when i found out

It looks like your problem is in clock applet (library plasma_applet_clock.so). It is part of plasma-widgets-workspace, where is also battery applet -> this package probably needs to be rebuilded against actual libraries...

I just closed the clock applet and then the same KDE error box appeared:
I attached the info given at this crash.

This might have been the problem, thank you.

"I just closed the clock applet and then the same KDE error box appeared:
I attached the info given at this crash.

This might have been the problem, thank you."

You can try logging out without the battery or clock applets to see if the error still appears, and that will give confirmation.

Ok, I did not experience any KDE crash anymore when logging out.
Seems that the clock application is some kind of corrupt.
Thank you guys!

the bug still exists but this thread
http://ubuntuforums.org/showthread.php?p=9203854
gives a solution.
It seems the bug comes from the login manager kdm.
Switching to gdm allows logout and shutdown.

That's a different bug with similar symptoms.

ok Scott.
I didn't manage to find the bug report for the bug I mentionned wich have similar symptoms.
Scott, do you know wich bug report is it?
Thank you!

If you can't find one, file a new one.

same kind of problem on Kubuntu 10.10 since upgrading to KDE sc.4.6.0