Several XFCE applications appear unresponsive after communicating with a daemon

If this turns out to have anything to do with Bug #1314782, then the issue lies not in D-Bus but in Ubuntu patches to GTK+ conflicting with Xubuntu patches to XFCE apps (or possibly with the apps originally). I don't remember the exact details but whoever triages/investigates this should get in touch with the Xubuntu team.

@ Xubuntu Developers:

Please, could you give your thoughts on this?

It severely affects packages beyond the one that causes the flaw.

Related Xfce4-dev mailing list entry:

https://mail.xfce.org/pipermail/xfce4-dev/2014-May/030715.html

Thanks for the triaging effort! As far as I know xfce4-volumed-pulse has a fix committed already though I'll let mrpouit confirm. The ALSA xfce4-volumed never had the issue.

A Thousand Thanks.

in English we would say "unresponsive" rather than "irresponsible".

On Tue, Jul 29, 2014 at 8:15 AM, Bug Watch Updater <
<email address hidden>> wrote:

> ** Changed in: xfce4-settings
> Status: Confirmed => Fix Released
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (973778).
> https://bugs.launchpad.net/bugs/1347272
>
> Title:
> Several XFCE applications appear irresponsible after communicating
> with a daemon
>
> Status in pixbuf library for gtk+:
> New
> Status in One Hundred Papercuts:
> Triaged
> Status in System policy:
> Confirmed
> Status in Thunar file manager:
> Confirmed
> Status in xfce4-appfinder:
> Confirmed
> Status in Xfce4 Power Manager:
> Confirmed
> Status in xfce4-settings:
> Fix Released
> Status in Volume management daemon for XFCE 4:
> Invalid
> Status in Volume management daemon for Xfce:
> Confirmed
> Status in “gdk-pixbuf” package in Ubuntu:
> Triaged
> Status in “policykit-1” package in Ubuntu:
> Triaged
> Status in “thunar” package in Ubuntu:
> Triaged
> Status in “xfce4-appfinder” package in Ubuntu:
> Triaged
> Status in “xfce4-power-manager” package in Ubuntu:
> Triaged
> Status in “xfce4-settings” package in Ubuntu:
> Triaged
> Status in “xfce4-volumed” package in Ubuntu:
> Triaged
>
> Bug description:
> Several programs in Xfce have a daemon mode call gtk_init() before
> fork()ing.
>
> This is unsafe, and when it goes wrong this will typically manifest as
> the daemon hanging shortly after forking, and appearing to simply do
> nothing at all.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/gdk-pixbuf/+bug/1347272/+subscriptions
>

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Hi Alberto,

Thanks for compiling all this information. There's a couple of pieces missing though.

This bug doesn't happen as far as I know with vanilla Gtk. It happens when the Unity Gtk extensions (dbusmenu and overlay scrollbar) are loaded. They are Gtk plugins and one or both of them open dbus connections as soon as they are loaded. They are loaded at Gtk init and that dbus connection becomes invalid after the fork, but Gtk tries to reuse it anyway. That causes it to hang.

As a result of the above, this bug only happens if you have Unity installed alongside the affected software eg Xfce. So a good way to spot duplicates is to ask if the user also has Unity installed if they are not using it.

Another thing is that those Gtk extensions should not be loaded at all outside of Unity. There is a bug about that: https://bugs.launchpad.net/ubuntu/+source/xfce4-indicator-plugin/+bug/1307657

Finally, we don't have a metabug like this upstream at Xfce because bugzilla is not good at handling those types of bugs, but we are aware of the issue and there is a thread on the mailing list about it. https://mail.xfce.org/pipermail/xfce4-dev/2014-May/030715.html

The conclusion we reached is that even though this is ultimately caused by Unity extensions, each application should be fixed to fork *before* it calls Gtk init, because you never know what extra plugins might get loaded and subsequently break.

@ Alistair,

I don't explicitly have Unity installed (I'm on Xubuntu 14.04), but a search via synaptic shows that I do have these Unity-related packages installed, possibly as dependencies for some piece of software I was compiling:

gir1.2-unity-5.0 7.1.4+14.04.20140210-0ubuntu1
libunity-protocol-private0 7.1.4+14.04.20140210-0ubuntu1
libunity-scopes-json-def-desktop 7.1.4+14.04.20140210-0ubuntu1
libunity9 7.1.4+14.04.20140210-0ubuntu1
unity-gtk-module-common 0.0.0+14.04.20140403-0ubuntu1
unity-gtk2-module 0.0.0+14.04.20140403-0ubuntu1
unity-gtk3-module 0.0.0+14.04.20140403-0ubuntu1

Also, I don't have any overlay-scrollbar packages installed, but I do have these dbusmenu packages installed:

gir1.2-dbusmenu-glib-0.4 12.10.3+14.04.20140612-0ubuntu1
libdbusmenu-qt-dev 0.9.3+14.04.20140314-0ubuntu1
libdbusmenu-qt2 0.9.3+14.04.20140314-0ubuntu1

@mspacek

The unity-gtk-module packages are the trouble makers in this particular case, per the "UBUNTU_MENUPROXY should not be set in Xfce" bug. But that's only half the problem and having those loaded in Xfce causes other problems. The late fork() problems can potentially be triggered by other bugs also, so both these bugs need to be independently fixed. As such, I've unset the duplicate.

Should bug #1222356 (** (apport-gtk:3020): WARNING **: Couldn't register with accessibility bus: Did not receive a reply.) perhaps be marked as a duplicate?

The string gtk_init does not appear in polkit codebase.

Alberto, the reports which are related to polkit/pkexec and have been marked as duplicate should be unlinked then, right?

Any chance to get the bugfix into trusty?

xfce-bugs #11045 is fixed, see
https://bugzilla.xfce.org/show_bug.cgi?id=11045

commit 791f02416560f5ac75250a9a67f4e2a3d0ac6f7c
Author: Eric Koegel <email address hidden>
Date: Mon Jul 28 09:03:30 2014 +0300

http://git.xfce.org/xfce/xfce4-settings/commit/?id=791f02416560f5ac75250a9a67f4e2a3d0ac6f7c

Seconded for getting this into Trusty. This bug has caused me so much grief over the past few months...

All this has been fixed via this SRU for trusty: https://launchpad.net/bugs/1307657

Furthermore this has all been taken care of upstream, so this should not cause any further troubles for anyone.

Just thought I'd mention that this problem does seem to have gone away for me in trusty. Not sure when that happened, but I'm glad it's (apparently) fixed. Thanks!

Just upgraded to trusty and the problem is still here. I mostly notice it opening the xfrun4 prompt. I have noticed if I reboot it will sometimes be fine.

Apparently fixed in 4.11- https://bugzilla.xfce.org/show_bug.cgi?id=11043

Will 4.12 be coming to Trusty?

I'm having the problem in wily with xfce4-volumed - it doesn't react to multimedia volume keys.