XAMPP : World-writable config file /etc/my.cnf is ignored

Maybe You're so generous when set /etc/my.cnf (or /opt/lampp/etc/my.cnf) to 777 - worldwide-writable), then MySQL won't start.

To fix the problem :
chmod 644 /opt/lampp/etc/my.cnf

http://hecode.com/how-to-fix-world-writable-config-file-etcmy-cnf-is-ignored/