VirtualBox 6.0.10 segfaults at startup on CentOS 7.6

[gottschalk_maria]

> VirtualBox
Segmentation fault
>

Kernel logs this:

UINetworkReplyP[15063]: segfault at 2ad601cd1550 ip 00002ad629dc4f7e sp 00002ad6296ee2f8 error 7 in libkdecore.so.5.14.8[2ad629d20000+2b9000]

My understanding is that 6.0.10 now somehow manages to load libkdecore.so.5.14.8 which is from KDE4. (I'm not using KDE4, I just have some KDE programs installed.)

First guess is it's triggered from here:

https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Frontends/VirtualBox/src/net/UINetworkReply.cpp

Downgrading to 6.0.8 makes Virtualbox work again.

[gottschalk_maria]

It seems VirtualBox is now using libproxy, which contains a KDE4 module. This KDE4 module depends on Qt4 and loading it into a Qt5 program results in a segfault.

Workaround: yum remove libproxy-kde

[Michael Thayer]

I wonder whether this should be considered a bug in CentOS? EPEL seems to contain Qt5, so it is use case which ought to work.

[Michael Thayer]

Actually the main CentOS repository has Qt 5.9:

​http://vault.centos.org/7.5.1804/os/x86_64/Packages/qt5-qtbase-5.9.2-3.el7.x86_64.rpm

[gottschalk_maria]

RHEL/CentOS/OL have both qt4 and qt5 which can be installed in parallel. But there is only KDE4 which is qt4-based. Hence the KDE4 module for libproxy is also qt4-based. Loading it in a qt5 program results in the crash mentioned. One could argue this is a libproxy bug. But VirtualBox could live without libproxy until 6.0.10.

I'm using the official rpm for RHEL/CentOS/OL. It includes its own copy of qt5-5.6.x.