Beware to try to use /dev/null as a drop target for syslog-ng by using something like the following in your syslog-ng.conf:
destination d_drop {
file("/dev/null");
};
This will chmod your /dev/null file to 0600 (also known as crw-------) at every startup and cause many failures on your system/server. Use an empty target to drop your log messages:
destination d_drop {
};