O procedimento aceito está escrito aqui:
Trecho:
If you notice a problem in Ubuntu, you can file a bug report.
Type Alt+F2 and type ubuntu-bug nameofprogram
If you have a hardware issue or don't know the name of the program affected, just type ubuntu-bug
After running one of the above commands, Ubuntu will gather information about the bug. This may take a few minutes. Review the collected information if you wish. Click Send to continue.
A new web browser tab will open to continue processing the bug data. Ubuntu uses the website Launchpad to manage its bug reports. If you do not have a Launchpad account, you will need to register for one to file a bug and receive email updates about its status. You can do this by clicking Create a new account.
After logging in to Launchpad, enter a description of the problem in the summary field.
After clicking Next Launchpad will search for similar bugs in case the bug you are reporting has already been reported. If the bug has already been reported, you can mark that bug as also affecting you. You can also subscribe to the bug report to receive updates about progress with fixing it. If the bug has not already been reported, click No, I need to report a new bug.
Fill in the description field with as much information as you can. It's important that you specify three things:
What you expected to happen
What actually happened
If possible, a minimal series of steps necessary to make it happen, where step 1 is "start the program"
Your report will be given an ID number, and its status will be updated as it is being dealt with. Thanks for helping make Ubuntu better!