Bug 400667 - Task bar froze when kde is run under kernel RT
Summary: Task bar froze when kde is run under kernel RT
Status: RESOLVED WORKSFORME
Alias: None
Product: plasmashell
Classification: Plasma
Component: Task Manager and Icons-Only Task Manager (show other bugs)
Version: 5.12.6
Platform: Fedora RPMs Linux
: NOR normal
Target Milestone: 1.0
Assignee: Eike Hein
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-11-04 15:43 UTC by ycollet
Modified: 2018-12-20 03:44 UTC (History)
3 users (show)

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Latest Commit:
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Description ycollet 2018-11-04 15:43:29 UTC
The Kde Task bar froze really often when I run KDE under a realtime kernel.

Everything in the taskbar is frozen (the clock, the menu, all the icons of the launched application). But I am still able to use application (I switch between applications using alt+tab).

I recover the task bar if I disconnect / reconnect from my session.

I use Fedora 27 + last KDE version.

Kernel RT is 4.18.12-rt8.
Comment 1 David Edmundson 2018-11-04 17:21:38 UTC
Is the desktop froze? Does it react to right click?

Please get a backtrace of the frozen process.
Comment 2 ycollet 2018-11-04 17:25:58 UTC
I've got no reaction to a right click on the task bar. But I don't remember if I was able to get a reaction to a right click on the desktop. I think the answer is no because I tried to start konsole to see what's happening. And I must have done a right click on the desktop. But I will check.

How do I get a backtrace of the frozen process ?
How do I identify the frozen process ?
Comment 3 David Edmundson 2018-11-04 17:42:51 UTC
From a terminal when frozen

Sudo gdb --pid `pidof plasmashell`

Then type "bt" to get a trace
Comment 4 ycollet 2018-11-05 18:03:50 UTC
I met the freeze again. 
In fact, this was not a freeze.
I looked at the plasmasheel processes:
$ ps -elf | grep plasma
0 Z collette  1776     1  2  80   0 -     0 task_d 18:11 ?        00:01:18 [plasmashell] <defunct>
0 S collette 21709 12626  0  80   0 - 29882 -      19:01 pts/2    00:00:00 grep --color=auto plasma

So, plasmashell was dead.
I killed it via a kill -15 and then restarted manually plasmashell ...
Comment 5 David Edmundson 2018-11-05 18:50:17 UTC
So are you saying it's a crash?
Comment 6 ycollet 2018-11-05 18:52:51 UTC
More a crash than a freeze. 
I thought it was a freeze because the taskbar was still there.
Comment 7 Bug Janitor Service 2018-11-20 04:47:34 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 8 ycollet 2018-11-20 08:18:49 UTC
It's still not working !

I am waiting on advices on how to get useful informations to track down this bug ...
Comment 9 Kai Uwe Broulik 2018-11-20 08:20:11 UTC
Reopening
Comment 10 Kai Uwe Broulik 2018-11-20 08:20:38 UTC
Nevermind, please provide a backtrace.
Comment 11 ycollet 2018-11-20 08:24:32 UTC
And how do I get this backtrace ?
Comment 12 Kai Uwe Broulik 2018-11-20 08:25:50 UTC
> From a terminal when frozen
> sudo gdb --pid `pidof plasmashell`
> Then type "bt" to get a trace

Or just start plasmashell with gdb, run gdb plasmashell and then type r for "run" and then when it freezes type "bt"
Comment 13 ycollet 2018-11-20 08:26:37 UTC
Thanks, I will try this ASAP.
Comment 14 Bug Janitor Service 2018-12-05 03:44:17 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 15 Bug Janitor Service 2018-12-20 03:44:21 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!