Created attachment 315725 [details]
The stack trace produced with "thread apply all bt full"

Tested on
- Fedora 23
- Rhythmbox 3.2.1
- clutter 1.24.2
- KDE 5 with Plasma/X11 5.4.3

All packages were from the official Fedora repositories.

Steps to reproduce:
1. Open rhythmbox
2. Click "gear"->plugins
3. Enable the "Visualizations" plugin
4. Begin playing a song
5. Click on the "Visual Effects" icon in the left pane
6. Double click the visualization window to activate full-screen mode

Expected results:
Rhythmbox continues playing music and the visualization displays in fullscreen mode.

Received results:
Rhythmbox crashes


While running in GDB, upon performing step 5, the visualization displays in a distored fashion.


Upon performing step 6, rhythmbox prints the following errors:

(rhythmbox:21736): Clutter-CRITICAL **: The Clutter backend is not a X11 backend
[New Thread 0x7fff95fb7700 (LWP 21805)]

(rhythmbox:21736): Clutter-CRITICAL **: The Clutter backend is not a X11 backend

Program received signal SIGSEGV, Segmentation fault.

Attached is a backtrace produced with the command "thread apply all bt full".


The direct cause of the segfault is somewhere in X11. This is the output of the command "list":

Program received signal SIGSEGV, Segmentation fault.
XInternAtom (dpy=dpy@entry=0x0, name=name@entry=0x7fffffffc1f0 "_XSETTINGS_S0",
    onlyIfExists=onlyIfExists@entry=0) at IntAtom.c:174
174         LockDisplay(dpy);
(gdb) list
169         int idx, n;
170         xInternAtomReply rep;
171
172         if (!name)
173             name = "";
174         LockDisplay(dpy);
175         if ((atom = _XInternAtom(dpy, name, onlyIfExists, &sig, &idx, &n))) {
176             UnlockDisplay(dpy);
177             return atom;
178         }

This is the value of dpy:

(gdb) p dpy
$1 = (Display *) 0x0
(gdb)

The backtrace makes me think this has something to do with either clutter or libmx.