Hi,

I started reading linux device drivers by rubini. As the part of the book i try to compile and load a simple module. It compiled well but when i m trying to inserting this i m facing a version mismatch problem.
The program looks like this

#define MODULE
#include<linux/module.h>

int init_module(void)
{
printk("<1> Hello \n");
return 0;
}

void cleanup_module(void)
{
printk("<1> Bye \n");
}

I compiled the prog as
gcc -c firstmod.c

But when i try to insert the module with the following command

insmod firstmod.c
I m getting the following error message.
Module is compiled for a different kernel and u r inserting into a kernel whose version is different. It is saying that "Version mismatch occurs". And it is saying that version of kernel for which my module is compiled is 2.4.20 and where as kernel version into which im inserting module is 2.4.20-8. But how can it is possible. When i used uname to print info it prints my kernel version as 2.4.20-8. Then how can module is compiled with the kernel 2.4.20

By this output what i understood is my module is compiled with a kernel header whose version is different than the kernel into which i m inserting my module. But i dont know how can i solve this problem. I m using red hat 9.0 on pentium 4 machine. Can any body help me to resolve this version mismatch.

Thanx in advance.
Rajesh.

Check the Makefile version number in the linux sources..

Hi

Can u plz tell me how to check the makefile version. I have two directories in /usr/src folder one linux-2.4 and another one is linux-2.4.20-8. Thanx in advance.

Rajesh.

That would depend on the linking to the linux headers you are using during your build..

You may find that linux-2.4 is a symlink to linux-2.4.20-8..
Either way, look at the files /usr/src/linux-2.4/Makefile and /usr/src/linux-2.4.20-8/Makefile
These determine the version number used by the built kernel and modules.
You need to have done at least make dep to create the linking that fixes the version number.
Whatever the version & extraversion show in the Makefiles, use that as the name of the directory the sources are in.
Then create symlinks /usr/src/linux and /usr/src/linux-2.4 to the directory with 2.4.20-8 name
If the sources have not been used for a kernel/module build, do make dep to prepare them.

shouldn't that be
insmod firstmod.o
???

well i guess it should be insmod file_name.ko to inserte the module and rmmod file_name.ko

After compiling and linking the .c file you will get .ko file ......Please correct me if i am wrong ....
Thanks
Misbah Khan