Apps printing a lot of text to stderr eventually freeze when run with gksu

Bug #1216045 reported by Vlad Orlov on 2013-08-23
This bug affects 6 people
Affects Status Importance Assigned to Milestone
libgksu (Ubuntu)

Bug Description

Encountered in Ubuntu 13.04 and Mint 15.

Steps to reproduce:

Method A:

1. gksu synaptic
2. Turn off "Settings -> Preferences -> General -> Show package properties in the main window" if it was on (or else you won't get a lot of warnings in stderr).
3. Click on package list and start browsing it with Up and Down keys. You may also use the mouse, but it will take more time.

Additional info:
The big load of messages thrown to stderr is described here:
The freeze itself is reported here:

Method B:

1. Download the archive from the attachment and unpack it.
2. Install g++ and libgtkmm-3.0-dev
3. g++ -o test `pkg-config gtkmm-3.0 --cflags --libs`
4. chmod +x test
5. gksu ./test
6. Start clicking on the button (or pressing Enter)

Additional info:
The source code was taken from gtkmm examples:
HelloWorld::on_button_clicked() function was modified to print 20 pretty long messages to stderr (to simulate what happens to Synaptic in Method A). You can set this count higher or lower.
With messages number set to 20 there's an interesting side effect: shortly before freeze, one of these messages gets actually printed to the console instead of being buffered until the app termination.

Vlad Orlov (monsta) wrote :
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in libgksu (Ubuntu):
status: New → Confirmed
Vlad Orlov (monsta) wrote :

The situation is still exactly the same in Ubuntu 13.10, and I'm not sure who to subscribe to this bug to get it fixed.

Ansgar Bohmann (aldi) wrote :

I do also experience synaptic freezing in Saucy Salamander (Ubuntu 13.10) with Unity. I have two computers (one laptop, one desktop) both showing the same behavior. So far I've always called synaptic from a terminal window (with a bash) via "gksudo synaptic &". Most of the time synaptic works well for some seconds to minutes and then locks with no obvious reason and without any error message. Sometimes I can close the window but the synaptic-process does not get killed. Only after "sudo pkill synaptic" synaptic actually is killed and error messages start flooding the terminal.

I hope this bug gets fixed (regardless whether it's a problem with synaptic or gksu).

Vlad Orlov (monsta) wrote :

In Xubuntu 14.04, method A doesn't work anymore (Synaptic has been fixed), but method B still returns the same result: the app freezes. The only change is that I couldn't get it to show the buffered stderr output after the app termination.

Can anyone fix this before 14.04 release?

Vlad Orlov (monsta) wrote :

Congratulations developers, you've released LTS with this bug.

Vlad Orlov (monsta) on 2014-05-19
description: updated
Vlad Orlov (monsta) wrote :

Any progress on this?

Vlad Orlov (monsta) on 2015-03-22
tags: added: trusty utopic vivid
Changed in libgksu (Ubuntu):
importance: Undecided → High
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