I cannot fix the icons on Gitlab bring proxied by Apache 2.4. My failure may be because I am not using passenger (passenger provided its own set of problems that were much deep
This might help you,
https://github.com/gitlabhq/gitlabhq/issues/3306#issuecomment-15971720
Basically it's saying to run a rake assets:clean and then a assets:precompile and then a service gitlab restart
I had precompiled my assets, checked the public/assets folder and could see they existed but some icons were not showing so I cleaned them out, precompiled again and restarted it then they started showing up.
Run
sudo -u git -H bundle exec rake assets:clean RAILS_ENV=production
Then
sudo -u git -H bundle exec rake assets:precompile RAILS_ENV=production RAILS_RELATIVE_URL_ROOT=/gitlab
And refresh the page, if it's not working try
sudo service gitlab restart
But I looked in my history there now and I couldn't see myself restarting it so I am assuming that when this happened to me I simply cleaned them out and precompiled them again and I didn't have to restart.