Wallch 4.0: Floating point exception

[Alin Andrei]

I'm trying to use Wallch 4.0 (under Ubuntu 14.04 with Unity) but when I click the "Start" button on the "Wallpapers" tab, the first time nothing happens and the second time I click "Start", the following error is displayed: "Floating point exception".

If however I start wallch with "--start" via coomand line, it works.

[Leon Vitanos (leon-mellori)]

We need some more information so we can reproduce the error and probably fix it

1. Which daily build of Ubuntu 14.04 are you using?
2. The folder of the wallpapers, is it Ubuntu Desktop Bakcgrounds or is it a folder with Pictures that you have downloaded?
If it is with your own Pictures, do you have the same problem with Ubuntu Desktop Backgrounds?
3. You click start, and nothing happens? Not even the process starting?
4. How do you see the "Floating point exception" error? A message pops up, you are running wallch from terminal? and after that error, the application crashes or just does nothing?
5. Does the other features work? For example LIve Earth Wallpaper?

[Alin Andrei (nilarimogard)]

1. I don't know what you mean, this question doesn't make sense... I'm using Ubuntu 14.04 with all packages up to date...

2. It's the default folder (Ubuntu Desktop Backgrounds folder). I've also tried a different folder and the behaviour is exactly the same: the first time I click the "Start" button, it does nothing and the second time I click it, Wallch crashes and the "floating point exception error" is displayed in the terminal.

3. Yes, the first time I click "start", nothing happens: the button doesn't do anything and there's no output in the terminal.

4. The "floating point exception error" is displayed in the terminal (I ran "wallch" in a terminal to see why it doesn't work).

5. Yes, I've tried the Live Wallpaper and it works.

[Alex Solanos (hakermania)]

Hello Alin, and thanks for your bug report.

The final 4.0 version of Wallch is available at https://launchpad.net/~wallch/+archive/wallch-4.0/+packages

Be sure to have this version installed into your system. Answering now to your answers to Leon's points:

1. Ubuntu 14.04 has yet to be released. It is to be released this April. For now, daily builds are available here: http://cdimage.ubuntu.com/daily-live/current/ As you understand, his question makes sense ;)

2. This means that it hasn't to do with some file containing some special character or anything like this; it is probably a problem with the version of Wallch you are using.

3, 4, 5. Thanks for the information.

I just installed Ubuntu 14.04 daily build (24 Feb's one) from the link I posted above and Wallch from the link I posted above, and it works just fine.

Please keep us updated :)

[Alin Andrei (nilarimogard)]

I know version 4.0 is available in that PPA and it's also available in the official Ubuntu 14.04 repositories since today: https://launchpad.net/ubuntu/trusty/+source/wallch/4.0-0ubuntu1

As for 1), It doesn't matter which daily ISO I've used since you can install updates... :) Even though I've installed a daily alpha image, when the final version comes out, I'll be using the final Ubuntu 14.04, wouldn't I?

Well, the bug exists, I have no idea what's causing it but it occurs for me. I can help debug if you want. I wanted to write about it on webupd8.org but since it doesn't work, I can't.

[Alex Solanos (hakermania)]

That's weird. I cannot reproduce in any way.

This bug strongly reminds me of a bug we had encountered while developing Wallch. We pushed the Start button and it acted like it was pushed 2 times (Start and then Pause). Clicking again the button crashed the application.

The bug has long been fixed, though.

Let's try some troubleshooting:

sudo apt-get remove wallch && rm -rf /usr/bin/wallch /usr/share/wallch ~/.config/wallch ~/.wallch ~/.cache/wallch

Then try re-installing Wallch 4.0 from the repos. Be sure you haven't any wallch PPA enabled or anything. The best you could do would be to manually download the DEB and double-click it.

PS: I installed Ubuntu 14.04 daily build a couple of hours ago to test your bug report and this one: https://bugs.launchpad.net/bugs/1284174 As you can see in my reply, I show Wallch working fine (clicking the Start button etc). The weird thing is that after I updated & upgraded & restarted, I still couldn't find Wallch 4.0 into USC, only Wallch 3.01. I know it has been uploaded into the repos, though. That's why I think that you *may* be installing by some outdated PPA.

[Alin Andrei (nilarimogard)]

I tried removing everything and reinstalling but it didn't help, the bug still occurs.

Did you test it in Ubuntu 14.04 running in VirtualBox or on bare metal? I ask this because it works for me in VirtualBox in Ubuntu 14.04 but even though it works, this is displayed when running wallch in a terminal:

OpenGL Warning: glFlushVertexArrayRangeNV not found in mesa table
OpenGL Warning: glVertexArrayRangeNV not found in mesa table
OpenGL Warning: glCombinerInputNV not found in mesa table
OpenGL Warning: glCombinerOutputNV not found in mesa table
OpenGL Warning: glCombinerParameterfNV not found in mesa table
OpenGL Warning: glCombinerParameterfvNV not found in mesa table
OpenGL Warning: glCombinerParameteriNV not found in mesa table
OpenGL Warning: glCombinerParameterivNV not found in mesa table
OpenGL Warning: glFinalCombinerInputNV not found in mesa table
OpenGL Warning: glGetCombinerInputParameterfvNV not found in mesa table
OpenGL Warning: glGetCombinerInputParameterivNV not found in mesa table
OpenGL Warning: glGetCombinerOutputParameterfvNV not found in mesa table
OpenGL Warning: glGetCombinerOutputParameterivNV not found in mesa table
OpenGL Warning: glGetFinalCombinerInputParameterfvNV not found in mesa table
OpenGL Warning: glGetFinalCombinerInputParameterivNV not found in mesa table
OpenGL Warning: glDeleteFencesNV not found in mesa table
OpenGL Warning: glFinishFenceNV not found in mesa table
OpenGL Warning: glGenFencesNV not found in mesa table
OpenGL Warning: glGetFenceivNV not found in mesa table
OpenGL Warning: glIsFenceNV not found in mesa table
OpenGL Warning: glSetFenceNV not found in mesa table
OpenGL Warning: glTestFenceNV not found in mesa table
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: glXGetFBConfigAttrib for 0x8e3f3f0, failed to get XVisualInfo
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: glXGetFBConfigAttrib for 0x8e3f3f0, failed to get XVisualInfo
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: glXGetFBConfigAttrib for 0x8e3f3f0, failed to get XVisualInfo
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: glXGetFBConfigAttrib for 0x8e3f3f0, failed to get XVisualInfo
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: glXGetFBConfigAttrib for 0x8e3f3f0, failed to get XVisualInfo
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
OpenGL Warning: glXGetFBConfigAttrib for 0x8e3f3f0, failed to get XVisualInfo
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x8e3f3f0
OpenGL Warning: Retry with 0x8002 returne...

[Alex Solanos (hakermania)]

I always test apps in bare metal, clean install. I don't use Virtualbox a lot because my PC lacks RAM. After your bug and the other bug report I downloaded and installed the daily build on a clean install.

The OpenGL warning, just a guess, is because the Virtualbox lacks graphics support.

Your problem is not reproducible in any way, neither in my 32-bit laptop nor on the 64-bit one of my co-developer (in case it was an arch-dependent issue).

I insist that you install by hand the DEB package from https://launchpad.net/~wallch/+archive/wallch-4.0/+packages in case you haven't done so, yet.

Also, can you check if the md5 hash of the executable inside the DEB (you may extract the deb package and there is a file containing the hashes) matches the one in your /usr/bin/ folder?

[Alin Andrei (nilarimogard)]

I tried both the deb in the PPA as well as the one in the official Ubuntu 14.04 repositories - I've installed both manually (deb downloaded and install with dpkg -i). And everything seems to work except for the "Start" in the UI.

Since you din't test it in VirtualBox, it's clearly something related to my setup - maybe wallpaper file names or maybe something else. Hopefully I'l be the only one affected...

[Alex Solanos (hakermania)]

If this bug affects more people we will take a deeper look into it. For now I would suggest re-installing your system, or wait for the official Ubuntu 14.04 to be released and make a clean install.

Wallch links to melloristudio.com, and it is yet to be finished, so it isn't 100% ready for a review, anyway :D

[justen r meltz (justen)]

I have this bug, too, with the latest Ubuntu 14.04LTS beta (uname -a Linux HPZ400 3.13.0-19-generic #39-Ubuntu SMP Fri Mar 21 14:18:44 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux). I removed my old wallch, downloaded the new debian package linked to above (wallch_4.0-1trusty_amd64.deb), but am unable to install it. The installation requires I have libqt5core5. So I tried to install it that. I got a message saying libqt5core5 is obsolete and has been replaced with libqt5core5a. So I tried to install that, but I already have it installed. Looks like at some point my nightly 14.04 update replaced core5 with core5a.

Is this just a problem with the debian package?

For kicks, I went to Ubuntu Software center and searched for wallch. It had wallch 4.0-0ubuntu4 available. It installed fine. Now, hitting the start button the 2nd time doesn't crash the program. It just minimizes the windows. It doesn't change wallpapers.

[justen r meltz (justen)]

Well, what do you know? I tried installing things again using the debian package, and it again failed. So I tried installing via Ubuntu Software Center. Upon launch of SC, it reported a failed installation, I chose to fix it, and I installed wallch again from SC. It now works fine. No crashes. Wallpaper changes as expected.

 wallch --version
QEventLoop: Cannot be used without QApplication
QDBusConnection: system D-Bus connection created before QCoreApplication. Application may misbehave.
Wallch - Wallpaper Changer, Version 4.0

[Alex Solanos (hakermania)]

Weird things :/

We cannot reproduce any of the problems mentioned. I very much hope this problem does not exist with the final Deb included into the repos. The deb has been extensively tested in 32 and 64 bit architectures, it would be a pity to have a bug that we couldn't have predicted.

[Kane York (kanepyork)]

Now I'm getting this, too, after running the official upgrade.

Maybe there's something going on with a corrupted config file?

$ wallch --version
QEventLoop: Cannot be used without QApplication
QDBusConnection: system D-Bus connection created before QCoreApplication. Application may misbehave.
Wallch - Wallpaper Changer, Version 4.0

$ wallch
QEventLoop: Cannot be used without QApplication
QDBusConnection: system D-Bus connection created before QCoreApplication. Application may misbehave.
Floating point exception (core dumped)

Then I go to enable core dumps to get a coredump, and it stops breaking.
Sorry that I couldn't help, other than confirming that this is indeed happening.

[Alex Solanos (hakermania)]

Hello Kane, and thanks for your comment!

I had absolutely no problem at all with Wallch until I installed the official NVidia drivers for my 710M. Then Wallch would misbehave. I would click Start once and nothing would happen. If I clicked it once again, Wallch would crash.

But it wasn't the only Qt application to misbehave. QtCreator itself would not open and crash immediately.

After a system reboot though, the problem seemed to go for me.

I am not sure that this is a problem of Wallch itself, that's what concerns me the most.

[Alex Solanos (hakermania)]

I've fixed this bug for 14.04 (not released yet).

I will hopefully push an SRU soon.

[Russell Almond (almond-m)]

I'm not sure if this is related, but I'm getting a similar sounding problem in a clean install of 14.04. In particular, when I press "Start" the second time, if wallch crashes I get the following message in the error log:
Limu kernel: [ 453.455078] traps: wallch[4741] trap divide error ip:458897 sp:7fffff7b7f40 error:0 in wallch[400000+13a000]

I can get the wallpaper to change by using the command line client, but I get a simliar looking message.

wallch --version
QEventLoop: Cannot be used without QApplication
QDBusConnection: system D-Bus connection created before QCoreApplication. Application may misbehave.
Wallch - Wallpaper Changer, Version 4.0

Synaptic Package manager lists this a version 4.0-0ubuntu4.

There is at least on crash log that was uploaded with this.

I just noticed multiple copies of the wallch icon in my menu bar. I'm not sure if that has anything to do with this problem.

I'm going to try deleting the config and cache files and restarting wallch and see if that fixes anything.

[Russell Almond (almond-m)]

Simply restarting the cache and restarting wallch was not sufficient. It crashed again.

Then I started it from the command line wallch --start

and got the following message:
wallch --start
QEventLoop: Cannot be used without QApplication
QDBusConnection: system D-Bus connection created before QCoreApplication. Application may misbehave.
Error: The message '--start' could not be sent to Wallch.
Assuming that the previous Wallch instance crashed and starting a new one now. Sorry for this :)

It now appears to be working normally.

I'm not sure what is happening here, but it appears to be the nasty kind of intermittent bug.

[Alex Solanos (hakermania)]

Russell, thanks for you bug, but it has been fixed, as its status indicates. Please wait for its release :)

[Phil Pemberton (philpem)]

I've had this (Start not working the first time, then a SIGFPE when clicking it a second time) happen on a fresh install of Ubuntu 14.10.

A workaround *seems* to be to make sure your current wallpaper is one that Wallch has in its list of available wallpapers -- that is, on the Wallpapers tab, double click one of the wallpapers before clicking start.

If 14.10 includes this fix, then I'd argue that this fix isn't "released" at all.

[Phil Pemberton (philpem)]

#19: I meant to say "Then I'd argue that this isn't fixed at all".

[Alex Solanos (hakermania)]

Yeah this has not been fixed inside ubuntu, but it has been fixed and released in our PPA.

So the status is correct because this is not a bug on the Wallch's ubuntu package, this is a bug on Wallch itself.

[Don Geddis (don-geddis)]

Can I get some more details on this claim that "it has been fixed" and "please wait for its release"? That claim was posted on 5-19-2014. It is now 3-11-2016. I'm experiencing the same symptoms described in this bug report, needing to restart wallch 10-20 times (crashing with floating point exception) before it somehow luckily successfully manages to start (by clicking "start" twice).

I'm running Ubuntu 15.10, and wallch 4.0-0ubuntu4. In what version is this bug fixed?

[space s (spaceshaman)]

Using 15.10 and getting floating point exception, too. It seems reading/writing of ~/.config/wallch/Settings.conf makes it crash. If I remove the file and reconfig, it works again. Mostly after system crash or shutdown the file gets damaged. I would suggest a rotating config file write to the author.

[space s (spaceshaman)]

Shame I can't edit my comments. Anyways, seems like "seconds_left_interval_independence=p.900.2016:04:22:19:59:56" this line causing the problem. Well, all I can say buckle up cupcake there are other languages and numeric formats than English...