Fedora 16: "Oh no!" failure at log in (solution within)

I've just upgraded to Fedora 16, and it was an almost perfect upgrade except for one ugly problem.

Unlike my upgrade to Fedora 16 Beta, this upgrade of packages went well.  I used the preupgrade tool to download all the packages and let them update after a reboot: almost no input required.  However, when I went to log in to my system, I saw a useless error message:

"Oh no!  Something has gone wrong."

It then asks me to log out.  I quickly realised that nothing really seemed wrong.  I clicked on the full-screen error message and pressed alt-F4 to close it and continue working.  I didn't want to deal with this every time, so I figured out the source (method documented below):

The culprit is installed colour profiles from Fedora 15 causing a key component to crash invisibly in the background due to security policy issues.  Ugh.

Solution
On a terminal,

restorecon -r ~/.local/share/icc 

An idea situation would be to have random ICC colour profiles not cause this.

Problem Solving Method

• test a fresh account: does it have the problem?  No, so it must be my user's configuration.
• back up my configuration and then try resetting various parts to default until I can find the source of the problem.   
• With .config and .gnome2 reset, the problem persisted, so it must be something else
• Try resetting all configuration directories (/home/user/.somecfgdirname)
• alright, that worked, so it is in one of the . directories.
• I have 189 of them, so bisect my original configuration to narrow down its location
• Alright, a-m reset resolves the problem, so it's in there
• A quick scan and I see .local which seems relevant, as lots of applications store information in there.
• Testing my original configuration without my .local resolves the problem. 
• I don't want to get rid of everything in my .local
• Try removing .local/lib: problem still there
• Try removing .local/share: problem fixed
• Alright, which application is storing problematic files in .local/share?
• bisect again, it's in a-m
• bisect again, it's in h-m
• take a look, and icc, the colour profile configuration seems like a possible candidate
• Reset icc and bingo!  

Then feel stupid because I actually read about this very problem in Fedora 16's common bugs page (it's a wiki that has things added with work arounds until they are resolved).   However, I didn't think it was my problem because there it says that GNOME Shell fails, and I unfortunately knew that my GNOME Shell was still running, but just giving me an error message inexplicably. 

From the Fedora Project's common bugs page:

Starting GNOME Shell fails after upgrade from Fedora 15 with color profile installed

link to this item - Bugzilla: #741549
If you used the gnome-color-manager tool to install a color profile for any of your hardware in Fedora 15, then after upgrading to Fedora 16, you may not be able to log in to GNOME Shell with SELinux enabled. Login will fail with the "Oh no! Something has gone wrong" error screen that GNOME pops up if a component is crashing repeatedly.

The issue is caused by gnome-settings-daemon crashing when it encounters a color profile with an incorrect SELinux context: the correct context for color profiles changed between Fedora 15 and Fedora 16, but the upgrade process does not re-label existing profiles.


To resolve the issue, boot to a different desktop or to a console and run the command restorecon -r ~/.local/share/icc. After doing this, GNOME login should work correctly.

Problem solving

I like hunting and solving problems.   I like narrowing down causes, and combining bisection with intuition and existing knowledge to understand the source of such things.

Sadly, many users don't have the same knowledge.  They might not know where to start.  My Fedora 16 Beta installation problem, where it trashed my system partition, was potentially catastrophic but ultimately not a big deal because I could handle myself.  This ICC colour profile permissions problem is relatively simple, but thanks to an oblique error message, what could a "normal" user do?  It's stuff like this that prevents me from recommending an otherwise wonderful system to my friends.  I fear the problem is systemic.