VirtualBox Segfault with Qt 5.11 in Gnome

Floft · 2018-05-27 02:57:46

I upgraded to Qt 5.11 for all the qt5-{base,declarative,location,script,sensors,...} packages. However, now when running VirtualBox (5.2.12-1) in Gnome (3.28.2-1) with Qt 5.11 I get:

Qt WARNING: QSocketNotifier: Can only be used with threads started with QThread
Segmentation fault

And, in dmesg:

[ 2652.437759] traps: VirtualBox[8898] general protection ip:7f88d2ae125a sp:7fff59b688e0 error:0 in libX11.so.6.3.0[7f88d2ab4000+139000]

However, if I downgrade to 5.10, then launching VirtualBox works fine in Gnome:

sudo pacman -U /var/cache/pacman/pkg/qt5-base-5.10.1-8-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-declarative-5.10.1-4-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-location-5.10.1-2-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-script-5.10.1-1-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-sensors-5.10.1-1-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-svg-5.10.1-1-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-tools-5.10.1-1-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-wayland-5.10.1-3-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-webchannel-5.10.1-1-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-webengine-5.10.1-2-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-x11extras-5.10.1-1-x86_64.pkg.tar.xz /var/cache/pacman/pkg/qt5-xmlpatterns-5.10.1-1-x86_64.pkg.tar.xz

Any ideas? I tried it in Openbox and VirtualBox runs just fine with Qt 5.11.

Last edited by Floft (2018-05-27 16:52:27)

ooo · 2018-05-27 05:19:07

Gnome on Xorg or wayland?

I couldn't reproduce your issue initially, but after installing qt5-wayland, I get the same error and segfault.
After uninstalling qt5-wayland, virtualbox starts again.

Floft · 2018-05-27 05:52:24

Wayland, I think -- looking at ps, I see Xwayland running.

Well, that is indeed interesting. I removed 'qt5-wayland' and that appears to work. Cool. Thanks.

ooo · 2018-05-27 14:28:36

I wouldn't call this solved. Removing qt5-wayland simply works around the issue by using the xcb backend (I assume) instead of wayland.
If you didn't have this problem before, it's a regression in qt 5.11.

Lone_Wolf · 2018-05-27 15:02:33

ooo wrote:

If you didn't have this problem before, it's a regression in qt 5.11.

I'd verify if a rebuild of virtualbox against qt5.11 solves it before calling it a regression.

ooo · 2018-05-27 17:02:59

As a non-native speaker, I thought regression would be an appropriate term even if you could solve the issue by rebuilding.

Nevertheless, I tried rebuilding, and the build failed for some seemingly not-simple cause.
Other qt5 applications (at least qjackctl) seem to work, so my guess is this is something that has to be fixed in virtualbox.

arojas · 2018-05-27 17:12:00

Qt 5.11 defaults to the Wayland backend on Wayland sessions. So if the bug, as it seems, is that Virtualbox crashes when run natively on Wayland then it is technically not a regression, it has simply surfaced now that Qt uses Wayland by default.

ooo · 2018-05-27 18:24:35

Thanks for the explanation arojas. That would make sense.
I couldn't find any bug reports for virtualbox that would confirm that it can't be started with wayland platform plugin though, but overall it's wayland support seems to be quite incomplete.

I suppose it would be good idea to confirm that virtualbox fails to start with same error using '-platform wayland' and qt 5.10.

For now, either removing qt5-wayland, or starting virtualbox with 'virtualbox -platform xcb' should work.

Floft · 2018-05-27 19:05:15

With Qt 5.11, 'VirtualBox -platform wayland' gives:

Qt WARNING: QSocketNotifier: Can only be used with threads started with QThread
Segmentation fault

[26795.830690] VirtualBox[24210]: segfault at 0 ip 0000000000000000 sp 00007ffec3d579b8 error 14 in VirtualBox[564c64c53000+25000]

I downgraded to 5.10 (as in initial post), then 'VirtualBox -platform wayland' gives:

Qt WARNING: QSocketNotifier: Can only be used with threads started with QThread
Segmentation fault

[26728.168462] VirtualBox[23467]: segfault at 0 ip 0000000000000000 sp 00007fff453b7828 error 14 in VirtualBox[560834df1000+25000]

ArchDoctor_needed · 2018-05-29 10:22:39

ooo wrote:

Thanks for the explanation arojas. That would make sense.
[...]
For now, either removing qt5-wayland, or starting virtualbox with 'virtualbox -platform xcb' should work.

I can verify that the workaround with 'virtualbox -platform xcb' is working in order to start the virtualbox.

But i can't get any image running

I'm getting the following error

The virtual machine 'Ubuntu1604-Server' has terminated unexpectedly during startup because of signal 11.
Result Code: 
NS_ERROR_FAILURE (0x80004005)
Component: 
MachineWrap
Interface: 
IMachine {85cd948e-a71f-4289-281e-0ca7ad48cd89}

May 29 13:01:14 PC gnome-shell[1231]: TODO: support set_buffer_transform request
May 29 13:01:14 PC gnome-shell[1231]: TODO: support set_buffer_transform request
May 29 13:01:14 PC gnome-shell[1231]: TODO: support set_buffer_transform request
May 29 13:01:14 PC kernel: VirtualBox[5147]: segfault at 2e2f00000001 ip 00007f1faef1125a sp 00007ffe1cda7100 error 4 in libX11.so.6.3.0[7f1faeee4000+139000]

Last edited by ArchDoctor_needed (2018-05-29 11:02:13)

ooo · 2018-05-29 14:56:45

ArchDoctor_needed, your error has nothing to do with the original issue on this thread.
Please read the CoC, especially this part: https://wiki.archlinux.org/index.php/Co … _hijacking

Floft · 2018-05-29 15:32:21

I noticed that as well when I ran 'virtualbox -platform xcb'. I can run the manager but as soon as I try to open a VM, the new window will die. Same when I tried "vboxmanage startvm ..." However, you can manually start the VM by name or ID with the command:

virtualbox -platform xcb --startvm "name or id here"

It's a little inconvenient. The alternative is to remove qt5-wayland, which means it'll default to xcb in both cases.

arojas · 2018-05-29 15:40:19

Floft wrote:

It's a little inconvenient. The alternative is to remove qt5-wayland, which means it'll default to xcb in both cases.

Or just export QT_QPA_PLATFORM=xcb

ArchDoctor_needed · 2018-05-29 16:00:16

Thanks again, that was the last piece to get the workaround running. I used the solution with

QT_QPA_PLATFORM=xcb

for convenience.

mmans0ur · 2018-06-12 05:57:15

I had the same problem for smplayer and wireshark ( all qt5 applications )
after removing qt5-wayland all get solved !
thanks for the topic

cornacchia · 2018-07-23 11:06:09

I'm having a similar problem, but running virtualbox with "-platform xcb" doesn't help.

Here are some details:

Command line output (it's the same with "-platform xcb"):

$ virtualbox
Segmentation fault

Dmesg:

VirtualBox[5889]: segfault at 7ffed1196f88 ip 00007f0a9bca85f4 sp 00007ffed1196f50 error 6 in libQt5Gui.so.5.11.1[7f0a9bab3000+574000]

Installed Qt packages:

qt5-base 5.11.1-1
qt5-declarative 5.11.1-1
qt5-location 5.11.1-1
qt5-multimedia 5.11.1-1
qt5-sensors 5.11.1-1
qt5-svg 5.11.1-1
qt5-webchannel 5.11.1-1
qt5-webkit 5.212.0alpha2-18
qt5-x11extras 5.11.1-1
qt5-xmlpatterns 5.11.1-1

Virtualbox packages:

$ pacman -Q | grep virtualbox
virtualbox 5.2.16-1
virtualbox-guest-dkms 5.2.16-1
virtualbox-guest-iso 5.2.16-1
virtualbox-guest-utils 5.2.16-1
virtualbox-host-dkms 5.2.16-1
virtualbox-ext-oracle 5.2.16-1

I'm using wayland:

$ pacman -Q | grep wayland
wayland 1.15.0-1
wayland-protocols 1.14-1
xorg-server-xwayland 1.20.0-9

Any ideas?

arojas · 2018-07-23 12:39:13

cornacchia wrote:

Any ideas?

You don't even have qt5-wayland installed, so your issue is not related to this post

Arch Linux

#1 2018-05-27 02:57:46

VirtualBox Segfault with Qt 5.11 in Gnome

#2 2018-05-27 05:19:07

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#3 2018-05-27 05:52:24

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#4 2018-05-27 14:28:36

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#5 2018-05-27 15:02:33

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#6 2018-05-27 17:02:59

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#7 2018-05-27 17:12:00

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#8 2018-05-27 18:24:35

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#9 2018-05-27 19:05:15

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#10 2018-05-29 10:22:39

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#11 2018-05-29 14:56:45

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#12 2018-05-29 15:32:21

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#13 2018-05-29 15:40:19

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#14 2018-05-29 16:00:16

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#15 2018-06-12 05:57:15

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#16 2018-07-23 11:06:09

Re: VirtualBox Segfault with Qt 5.11 in Gnome

#17 2018-07-23 12:39:13

Re: VirtualBox Segfault with Qt 5.11 in Gnome

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