* Nav Kamal <navkamal90@gmail.com> wrote (on 2013-11-20 16:43:26 +0000):
Am learning to write LKMs and wrote this program :
#include<linux/init.h> #include<linux/module.h> static int module_entry(void){ printk(KERN_ALERT "Hello World !!\n"); return 0; } static void exit_module(void){ printk(KERN_ALERT "Bye World .... \n"); } module_init(module_entry); module_exit(exit_module);
In this program if I change return value of function module_entry from 0 to something negative, the module fails to load. The error message is :
What was the exact value? Must be you returned -1, as an example try to pass some other lower negative numbers. It converts to error string using err or perror. So you get that permission denied for the value you passed.
"insmod: ERROR: could not insert module test.ko: Operation not permitted"
Failing to load module with negative return value is understandable but I can't understand why it says "Operation not permitted". Its not about user permissions, its about return value. Can somebody please guide me about this ?
Santosh -- When you really want something (and take the first steps in that direction), the entire universe will conspire to fulfill your desire. -- P. Coelho