Where are my printk messages?

I'm using Slack 8.1 and succesfully compiled the helloworld module.

I can load the module with insmod, I can then see it loaded with lsmod and I can unload it with rmmod.

However, I never see my printk messages anywhere.
I tried doing a cat of /var/log/messages and /var/log/syslog but don't see my output.

I'm doing all this work via ssh if that makes any diference.

Chris

root@slack-8-1:/usr/src/hellomod# cat hello.c
#define MODULE
#define LINUX
#define __KERNEL__
#include <linux/module.h>
#include <linux/kernel.h>
MODULE_LICENSE("Dual BSD/GPL");

static int hello_init(void){
printk("<1> Hello Mod Init!\n");
return 0;
}

static void hello_exit(void){
printk(KERN_WARNING "Hello Mod Exit!\n");
}

module_init(hello_init);
module_exit(hello_exit);
root@slack-8-1:/usr/src/hellomod#
root@slack-8-1:/usr/src/hellomod# lsmod
Module Size Used by Not tainted
pcmcia_core 40896 0
ide-scsi 7456 0
eepro100 17264 1
root@slack-8-1:/usr/src/hellomod# insmod hello.o
root@slack-8-1:/usr/src/hellomod# lsmod
Module Size Used by Not tainted
hello 336 0 (unused)
pcmcia_core 40896 0
ide-scsi 7456 0
eepro100 17264 1
root@slack-8-1:/usr/src/hellomod# rmmod hello
root@slack-8-1:/usr/src/hellomod# ls mod
/bin/ls: mod: No such file or directory
root@slack-8-1:/usr/src/hellomod# lsmod
Module Size Used by Not tainted
pcmcia_core 40896 0
ide-scsi 7456 0
eepro100 17264 1
root@slack-8-1:/usr/src/hellomod#

Are you inserting this "hello world" module into a remote kernel? If you are then the printk results are probably on the remote machine...Hope this Helps Gerard4143

Welcome to the forums

No, I'm inserting it right on the box I'm compiling it on.

Quote:

---

Originally Posted by chris123

I'm doing all this work via ssh if that makes any diference.

---

If your compiling and inserting on a local machine...why are you using ssh...

Becuase my wife demands I sit in the front room with her while she watches TV, but that's a whole other story.

Anyway, I just tried it right from the console and I still don't see them.

Chris

I tried compiling your Hello world module and it worked...the message(s) appeared in the /var/log/messages file...kernel - 2.6.27.7-9-default x86_64 GNU/Linux

Code:

---

//#define MODULE
//#define LINUX
//#define __KERNEL__

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

MODULE_LICENSE("Dual BSD/GPL");

static int hello_init(void)
{
        printk("<1> Hello Mod Init!\n");
        return 0;
}

static void hello_exit(void)
{
        printk(KERN_WARNING "Hello Mod Exit!\n");
}

module_init(hello_init);
module_exit(hello_exit);

---

Makefile

Code:

---

obj-m += test.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

---

Hi

you printk messages will be in /var/log/messages/dmesg

or just type

dmesg
at the end you will see you printk message