Howto: Build Linux Kernel Module Against Installed Kernel w/o Full Kernel Source Tree

This is untrue, /lib/modules/$(shell uname -r)/build is a symlink to the source tree. Title is misleading, you always need the at least the headers to build kernel modules.

Yes you need kernel headers but not source code from kernel.org (45+ MB tar ball). So title and post is correct.

probably kernel-devel*.rpm is required in addition to makefile
using /lib/modules.

Here’s one for you… I have a network interface that I need to re-compile every time the kernel is updated. This is for the realtek 8169 NIC.
Any way to automate this task on a yum update of a kernel?

If you are running the target kernel, then you should be able to do :

# make clean modules (as root or with sudo)
# make install
# depmod -a
# insmod ./src/r8169.ko

You can check whether the driver is loaded by using following commands.

# lsmod | grep r8169
# ifconfig -a

If there is a device name, ethX, shown on the monitor, the linux
driver is loaded. Then, you can use the following command to activate
the ethX.

# ifconfig ethX

,where X=0,1,2,…

If I go though this process on the local box after a kernel upgrade, I’m good to go, but it sucks that I have to do this..

Thanks,
Frank.

This is not clear enough for linux beginners. I am so sad that google placed this page so high in rankings.

Maybe you should try to make it a bit easier to understand (give more details or explain why you do that ‘hello.c’ thing).

Sincerely,
Dan

I don’t know how can I built a makefile?!
where should I define the PWD??!
please help me, I’m a beginner :D :-p

SOP is to follow the instructions line by line from beginning to end to make sure that they actually work before posting them as a “guide”.

There are too many holes here.

a) you don’t need to know exactly what verion of the kernel you have, $(uname -r) takes care of that for you.

b) what’s the difference beween $(uname -r) and $(shell uname -r)?

c) what about includes like #include etc that I see on the reference pages, here?

“See a detailed and complete example with C source code – how to Compiling Linux kernel module for more information.”

That code doesn’t work either. I can’t get the includes to work. If I hardcode them then they just reference other header files that don’t link properly because they have includes written the same way. I can’t even get that example to build.

touristguy87,

Under Ubuntu Linux 8.x install the following package (following will almost install every kernel source code file):

sudo apt-get install linux-headers-$(uname -r) linux-libc-dev kernel-package

Once done create hello.c as follows:
mkdir ~/hello
cd ~/hello
Create hello.c:

#include <linux/module.h>
#include <linux/kernel.h>

int init_module(void)
{
	printk(KERN_INFO "init_module() called\n");
	return 0;
}

void cleanup_module(void)
{
	printk(KERN_INFO "cleanup_module() called\n");
}

Create Makefile (note tabs are important):

obj-m += hello.o

all:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

Type following to build:
make
Sample output from my Ubuntu 8.10 box:

make -C /lib/modules/2.6.27-7-generic/build M=/tmp modules
make[1]: Entering directory `/usr/src/linux-headers-2.6.27-7-generic'
  CC [M]  /tmp/hello.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /tmp/hello.mod.o
  LD [M]  /tmp/hello.ko
make[1]: Leaving directory `/usr/src/linux-headers-2.6.27-7-generic'

HTH

ok also

obj := vs obj +=

at the top it is the former, the working code seems to be the latter

Here I also see
http://www.cyberciti.biz/tips/compiling-linux-kernel-module.html

obj-m = foo.o
KVERSION = $(shell uname -r)

and the orignal source:
http://www.tldp.org/LDP/lkmpg/2.6/html/hello2.html

has +=

this is pretty simple code once you’ve looked at it for 2 hours ;)

I think the main thing is that it has to point to $(uname -r)/build but you have to use $(shell uname -r) in the makefile -C part.

anyway I see plenty of variation in the basic syntax among the 5 or 6 examples on those 3 links.

I got it, somehow. I don’t know how.

I was getting the “can’t find target ‘make’ error”…I updated my system and rebooted and just tried make on a whim and it worked.

I used $(shell uname -r) in the Make file and += for the labels

also I removed the function-calls from the code.See the original example here:

http://www.tldp.org/LDP/lkmpg/2.6/html/hello2.html

Great content tips .All you need to do is customize them with your own …Thank you…

Thanks. Its what I was searchin for.

about the first module “hello.c ” , I had a problem ,
I installed my kernel headers but after “make” I was recieved this message …
Nothing to be done for ‘default’
and the second one as well ….
Nothing to be done for ‘all’

what shall I do ?

Can you provide more information on this, or do you have some resources you can share where i can get more of such stuff?

ERROR-1:
periyar:/home/saju/Desktop/hello-linux-module# apt-get install kernel-headers-$(uname -r)
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Couldn’t find package kernel-headers-2.6.26-1-686
——————————————–
ERROR-2 in Debian Lenny.
periyar:/home/saju/Desktop/hello-linux-module# make
make -C /lib/modules/2.6.26-1-686/build M=/home/saju/Desktop/hello-linux-module modules
make: *** /lib/modules/2.6.26-1-686/build: No such file or directory. Stop.
make: *** [all] Error 2

I solved first Error by #apt-get install linux-headers
But the second error not solved . Please help

periyar:/home/saju/Desktop/hello-linux-module# make
make -C /lib/modules/2.6.26-1-686/build M=/home/saju/Desktop/hello-linux-module modules
make[1]: Entering directory `/lib/modules/2.6.26-1-686/build’
make[1]: *** No rule to make target `modules’. Stop.
make[1]: Leaving directory `/lib/modules/2.6.26-1-686/build’
make: *** [all] Error 2

Its a wonderful introduction to a fresher to Linux.
Thanks I was frustated when I found that makefile should be “Makefile” !!!!!!!!

I tried this on CentOS5.4 and I cannot proceed after this:

[cuser@localhost test]$ make
make -C /lib/modules/2.6.18-164.el5/build M=/home/cuser/test modules
make: *** /lib/modules/2.6.18-164.el5/build: No such file or directory. Stop.
make: *** [all] Error 2

But, I do have kernel-devel and kernel-headers.

[cuser@localhost test]$ yum search kernel-headers kernel-devel
Loaded plugins: fastestmirror
============================ Matched: kernel-devel =============================
kernel-devel.x86_64 : Development package for building kernel modules to match
: the kernel.

=========================== Matched: kernel-headers ============================
kernel-headers.x86_64 : Header files for the Linux kernel for use by glibc
[cuser@localhost test]$

Could you help? If I figure this out, I can install the Broadcom BCM4312 wireless driver for Linux by Broadcom where I have the same issue.

Thanks a lot

a) read all of the above
b) make sure that your OS is fully up to date

Trust me, this does work.

help me how should i get rid of this error

sudo make
make -C /lib/modules/2.6.31-19-generic/build M= modules
make[1]: Entering directory `/usr/src/linux-headers-2.6.31-19-generic’
CHK include/linux/version.h
CHK include/linux/utsrelease.h
SYMLINK include/asm -> include/asm-x86
make[2]: *** No rule to make target `kernel/bounds.c’, needed by `kernel/bounds.s’. Stop.
make[1]: *** [prepare0] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.31-19-generic’
make: *** [all] Error 2