Bug 406970

Summary:	kwin_x11 crashes when switching virtual desktops
Product:	[Plasma] kwin	Reporter:	Jaakko Luttinen <jaakko.luttinen>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	crash
Priority:	NOR
Version First Reported In:	5.15.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	gdb stacktrace

Description Jaakko Luttinen 2019-04-27 13:14:07 UTC

SUMMARY


STEPS TO REPRODUCE
1. Enable System settings -> Desktop behaviour -> Virtual desktops -> Show on-screen display when switching.
2. Switch from one virtual desktop to another. 

OBSERVED RESULT

Kwin crashes and goes back to the original virtual desktop.

EXPECTED RESULT

Virtual desktop changes and Kwin continues working without crashing.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: NixOS 19.09.git.dfd8f84
(available in About System)
KDE Plasma Version: 5.15.3
KDE Frameworks Version: 5.57.0
Qt Version: 5.12.0

ADDITIONAL INFORMATION

Logs in journalctl between two consecutive crashes:

```
Apr 26 11:38:11 leevi xsession[2802]: KCrash: Application 'kwin_x11' crashing...
Apr 26 11:38:11 leevi xsession[2802]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 178, resource id: 56623111, major code: 20 (GetProperty), minor code: 0
Apr 26 11:38:11 leevi xsession[2802]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 179, resource id: 56623111, major code: 20 (GetProperty), minor code: 0
Apr 26 11:38:11 leevi X[2653]: (II) modeset(0): EDID vendor "LGD", prod id 803
Apr 26 11:38:11 leevi X[2653]: (II) modeset(0): Printing DDC gathered Modelines:
Apr 26 11:38:11 leevi X[2653]: (II) modeset(0): Modeline "1920x1080"x0.0  138.00  1920 1952 1988 2088  1080 1085 1090 1102 -hsync -vsync (66.1 kHz eP)
Apr 26 11:38:11 leevi xsession[2802]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 1242, resource id: 56623127, major code: 3 (GetWindowAttributes), minor code: 0
Apr 26 11:38:11 leevi xsession[2802]: qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 1243, resource id: 56623127, major code: 14 (GetGeometry), minor code: 0
Apr 26 11:38:12 leevi xsession[2802]: Application::crashHandler() called with signal 11; recent crashes: 2
Apr 26 11:38:13 leevi xsession[2802]: KCrash: Application 'kwin_x11' crashing...
```

Not sure if this is a problem in kwin or NixOS. Here's an issue on NixOS side for reference: https://github.com/NixOS/nixpkgs/issues/60312

Comment 1 Jaakko Luttinen 2019-04-27 13:32:48 UTC

I tried to get stacktrace with the following command but it just created an empty file (and gdb process quitted):

```
gdb --pid `pidof kwin_x11` 2>&1 | tee kwin.gdb
```

Comment 2 Jaakko Luttinen 2019-04-27 13:34:26 UTC

No, sorry, I just had a typo. Now it's working. Continuing..

Comment 3 Jaakko Luttinen 2019-04-27 13:45:27 UTC

Created attachment 119673 [details]
gdb stacktrace

Here is the gdb stacktrace.

Comment 4 Christoph Feck 2019-05-14 20:44:52 UTC

The crash is in QQmlTypeLoader. If this is reproducible with a recent Qt version (e.g. Qt 5.12.3), please report this issue with debug symbols directly to Qt developers via https://bugreports.qt.io/