Problem with User defined function

[yhou4]

Hi, everyone

I am new to MYSQL. I got a question in using UDF. Each time I have modified my
UDF function, the MySQL server restart itself automatically. I don't know if
it should be like this or I must do something wrong.

It happened like below:

1) I midify my UDF function and add it to the /usr/lib/.
2) I use "DROP FUNCTION func_name" to remove it first.
   At this moment, I got error message that can't connect with the server,
server goes away...
3) Then I found out that immediately the server restart itself
  and I can use DROP FUNCTION and CREATE FUNCTION successfully now.

Is it supposed to be like this?

Thanks  for any help

Yijue