[CentOS] empty /var/log/messages

>> I have one centos 4.0 server which /var/log/messages was always empty (0
>> bytes). I wonder what has been blocking the syslog to write the log.
>>
>
> Firstly, I'd suggest updating to 4.5.
>
> Secondly, is /tmp mounted with noexec option?

forgot to add, check /var/log/messages.* for current syslog messages