Created attachment 1434256 [details]
Description of problem:
boot the installer with inst.vnc option added,then the installation will end up with "pane is dead",as shown in the attached picture.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
Created attachment 1434257 [details]
Looking at anaconda.log, there is:
07:53:22,768 ERR core.util: Failed to import module docker from path /usr/share/anaconda/addons/com_redhat_docker/ks/docker.py in collect: No module named 'pyanaconda.iutil'
But I think that might not be fatal & has likely been happening for a while already.
On the other hand the isys segfault visible on the screenshot seems like the most likely reason why the Anaconda process died.
Proposed as a Blocker for 29-beta by Fedora user lnie using the blocker tracking app because:
seems affects the basic criteria " When using a dedicated installer image, the installer must be able to complete an installation using the text, graphical and VNC installation interfaces."
Discussed during the 2018-05-14 blocker review meeting: 
The decision to classify this bug as an AcceptedBlocker was made as it violates the following blocker criteria:
"When using a dedicated installer image, the installer must be able to complete an installation using the text, graphical and VNC installation interfaces"
The failure is caused by segfault in libxcb. The isys part is just a signal handler. Reassinging to libxcb.
This is blocking our nightly kickstart tests on rawhide.
Xvnc's GLX init wasn't quite right, fixed.
Verified working with compose Fedora-Rawhide-20180609.n.0
This bug seems gone,but unable to do vnc installation with inst.vncpassword boot option.
Please see #bz1592686 for more information,thanks.
As that's a different bug, let's close this one.