Several XFCE applications appear unresponsive after communicating with a daemon

[Martin Spacek]

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.

[Steve Dodier-Lazaro (sidi)]

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.

[Alberto Salvia Novella (es20490446e)]

@ Xubuntu Developers:

Please, could you give your thoughts on this?

[Alberto Salvia Novella (es20490446e)]

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

[Thaddaeus Tintenfisch (thad-fisch-deactivatedaccount)]

Related Xfce4-dev mailing list entry:

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

[Alberto Salvia Novella (es20490446e)]

Several programs 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.

Please check this bug is not affecting PolicyKit.

[Steve Dodier-Lazaro (sidi)]

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.

[Eric Koegel (eric-koegel)]

commit 216a5b750ccbe9fda98e0456a607230cd8c52303
Author: Eric Koegel <email address hidden>
Date: Thu Jun 26 19:46:46 2014 +0300

    Fork before gtk/dbus init

    https://mail.xfce.org/pipermail/xfce4-dev/2014-May/030715.html
    has the rational for the change.

http://git.xfce.org/xfce/xfce4-power-manager/commit/?id=216a5b750ccbe9fda98e0456a607230cd8c52303

So it shouldn't have that issue anymore. Do you still have startup issues with xfpm using the code from git/master? We haven't done a dev release with the commit in yet.

[Eric Koegel (eric-koegel)]

Created attachment 5567
Fork before gtk/dbus init

Hey, found another fork bug report. This should fix it in xfsettingsd.

[Eric Koegel (eric-koegel)]

Moving to xfsettingsd.

[awol (awol99)]

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
>

--
Sent from my recycled old computer.
[:C≡N:]− , I ≤ 2πrEħc ln 2

[Alistair Buxton (a-j-buxton)]

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.

[Martin Spacek (mspacek)]

@ 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

[Alistair Buxton (a-j-buxton)]

@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.

[Martin Spacek (mspacek)]

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

[Eric Koegel (eric-koegel)]

Thanks for confirming it Jani, making resolved.

[Alberto Salvia Novella (es20490446e)]

The string gtk_init does not appear in polkit codebase.

[Thaddaeus Tintenfisch (thad-fisch-deactivatedaccount)]

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

[Georg Altmann (george-george-net)]

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

[Robin McCorkell (xenopathic)]

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

[Bluesabre-1 (bluesabre-1)]

*** Bug 11036 has been marked as a duplicate of this bug. ***

[Simon Steinbeiß (ochosi)]

Appfinder was ported to GDbus, so this problem should be solved: 4a065a10945c72c985e254ff1ef13df188f3e11e

Released in 4.11.0

[Simon Steinbeiß (ochosi)]

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.

[Simon Steinbeiß (ochosi)]

Where did you see that in the code? As far as I can see, thunar daemonizes only after init.

[Snild (snild)]

Uhm, are you asking me? This was super-long ago, and I never really got all
the dbus stuff... Anyways, I don't remember. :)

//Snild
On Feb 22, 2015 9:45 PM, "Simon Steinbeiß" <email address hidden>
wrote:

> Appfinder was ported to GDbus, so this problem should be solved:
> 4a065a10945c72c985e254ff1ef13df188f3e11e
>
> Released in 4.11.0
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (1048805).
> https://bugs.launchpad.net/bugs/1347272
>
> Title:
> Several XFCE applications appear unresponsive after communicating with
> a daemon
>
> Status in One Hundred Papercuts:
> Fix Released
> Status in Thunar file manager:
> Invalid
> Status in xfce4-appfinder:
> Fix Released
> Status in Xfce4 Power Manager:
> Fix Released
> Status in xfce4-settings:
> Fix Released
> Status in Volume management daemon for Xfce:
> Fix Released
> Status in thunar package in Ubuntu:
> Fix Released
> Status in xfce4-appfinder package in Ubuntu:
> Fix Released
> Status in xfce4-power-manager package in Ubuntu:
> Fix Released
> Status in xfce4-settings package in Ubuntu:
> Fix Released
> Status in xfce4-volumed package in Ubuntu:
> Fix Released
>
> 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/hundredpapercuts/+bug/1347272/+subscriptions
>

[Thaddaeus Tintenfisch (thad-fisch-deactivatedaccount)]

*** Bug 11037 has been marked as a duplicate of this bug. ***

[Martin Spacek (mspacek)]

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!

[Luke Schlather (luke2760)]

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?

[Lastique (andysem)]

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