Uploader.php function _file_mime_type fails in CI 2.1

[eluser]Djaka PM[/eluser]
Hi my name is Djaka,
Currently I am facing an issue on the Upload library, I am using
- CI 2.1.0
- PHP Version 5.3.6-13ubuntu3.6

The issue actually not in the CI framework, but in a PHP function called "Fileinfo"
The Fileinfo function is called in CI`s _file_mime_type function inside Upload.php file ,
so my case is:

I am try to upload csv file, I already make sure that the file extension is correct and the allowed mime types are "csv|txt".

CI is already guess the file extension correctly("text/csv"), but by the time the CI called the "Fileinfo" function it return "text/plain", which is in my opinion is not correct.

Is there any workaround?
Some says that the "Fileinfo" is not quite reliable.
http://stackoverflow.com/questions/46071...e-from-php
For now I set the allowed mime types to wildcard, which will cause security issue.

Thanks.