From LQWiki

see: bug

a bug report lets the user tell the developer or maintainer that something is wrong with the software.

A good bug report will include:

• what the user was doing with the program when they saw the bug
• a complete list of relevant hardware
• any changes made to the system (new software installed or new hardware added
• the time when the bug was first noted
• a complete description of the bug
• why it's a problem

Before submitting a new bug, the user should check to see if anyone else has posted about the bug. If anything is different (say you use different hardware to the original reporter) then submit the report, including the bug title or number.