Bug 355878

Summary: Segfault in kactivitymanagerd when trying to initiate Plasma session via X2Go
Product: [Plasma] kactivitymanagerd Reporter: Fabian Köster <koesterreich>
Component: generalAssignee: Ivan Čukić <ivan.cukic>
Status: RESOLVED NOT A BUG    
Severity: crash CC: plasma-bugs
Priority: NOR    
Version: unspecified   
Target Milestone: ---   
Platform: Gentoo Packages   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: systemd journal

Description Fabian Köster 2015-11-25 09:17:24 UTC 
I am trying to initiate a remote Plasma session via X2Go but several crashes prevent Plasma from fully loading (e.g. no control panel). In dmesg, I see segfaults in kscreen_backend:

[   62.403979] kscreen_backend[2749]: segfault at 8 ip 00007fa77db17e83 sp 00007ffcd7be9b70 error 4 in 
KSC_XRandR.so[7fa77db00000+22000]
[   62.903996] kscreen_backend[2795]: segfault at 8 ip 00007f1f15b9fe83 sp 00007ffcef389b30 error 4 in 
KSC_XRandR.so[7f1f15b88000+22000]
[   62.941714] kscreen_backend[2811]: segfault at 8 ip 00007fc62e79be83 sp 00007fff8abf8f70 error 4 in 
KSC_XRandR.so[7fc62e784000+22000]
[   63.233484] kscreen_backend[2842]: segfault at 8 ip 00007fd3059f0e83 sp 00007ffcf12715c0 error 4 in 
KSC_XRandR.so[7fd3059d9000+22000]
[  187.681617] kactivitymanage[2754]: segfault at 7fcc7c03bc50 ip 00007fcc8b5ca071 sp 00007ffe917a2e38 error 4 in 
libQt5Sql.so.5.5.1[7fcc8b5b6000+3f000]


Reproducible: Always




Host (where Plasma is installed):

Gentoo Linux
Linux Kernel 4.2.6
Comment 1 Fabian Köster 2015-11-25 09:18:15 UTC 
Created attachment 95721 [details]
systemd journal

The systemd journal produced by journalctl -b.

Search for "x2go" to find the start of the faulty Plasma session.
Comment 2 Fabian Köster 2015-11-25 09:20:38 UTC 
See also related bugs 

Bug #353825 - Login by x2go in Plasma 5 crashes KCMInit 
Bug #355877 - Segfault in kscreen_backend
Comment 3 Fabian Köster 2015-11-25 09:21:37 UTC 
How can I get a full backtrace for those segfaults?
Comment 4 Ivan Čukić 2015-11-25 10:46:50 UTC 
This is a related problem I've found elsewhere:
http://www.itksnap.org/pmwiki/pmwiki.php?n=Documentation.XCBIssues

> Problems with Running ITK-SNAP over X11, NoX and X2GO
>
> When users try to run ITK-SNAP on a server (e.g., computing cluster front-end) with 
> limited video card resources, errors arise. A typical error is
>
> QXcbConnection: Failed to get the primary output of the screen
> QXcbConnection: XCB error: 172 (Unknown), sequence: 158, resource id: 150, major code: 149 
>
> Qt developers are working on this issue[1]. For the time being, we are providing a version of 
> [...]

[1] https://bugreports.qt.io/browse/QTBUG-31389

I'm marking this as invalid since it is not a problem of kactivities. The crash you are getting from kactivities is a known Qt issue that happens when the activities service is being shut down.

p.s. I don't mind continuing the discussion here, and if you find a solution to your problem, please do post it here. Unfortunately, I can not be of much help with the x2go setup. You can ping Martin G. on IRC to ask him whether he has some experience with this.
Comment 5 Fabian Köster 2015-11-25 11:27:22 UTC 
(In reply to Ivan Čukić from comment #4)
> I'm marking this as invalid since it is not a problem of kactivities. The
> crash you are getting from kactivities is a known Qt issue that happens when
> the activities service is being shut down.

OK, thanks for the fast response and the information you provided! I agree that this is not a bug in kactivities.