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Altera_Forum's avatar
Altera_Forum
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20 years ago

busybox rmmod doesn't work?

Hi!

I have a module with following source code: 

#include <linux/kernel.h># include <linux/init.h># include <linux/module.h>
 int __init hello_init(void)
 {
     printk("----------->Hello, world\n");
     return 0;
 }
 static void __exit hello_exit(void)
 {
     printk("------------>Goodbye, cruel world\n");
 }
 module_init(hello_init);
 module_exit(hello_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("testing module");
MODULE_AUTHOR("LS");

When I use the insmod command it works fine

hello.ko# busybox insmod hello.ko

----------->hello, world#

But when I use the rmmod command something going wrong:

# busybox rmmod hello.ko

rmmod: hello.ko: function not implemented#

What could be the reason?

Bye, Lothar.

6 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    a) Make sure, that you have the function rmmod.

    http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/cool.gif Make sure you have enabled Module unloading in your kernel. This feature isn&#39;t enabled by default. you will have to enable this function in your kernel configuration, rebuild your kernel and upload it.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    Hi

    The function to use is # busybox rmmod hello

    Thus, without the extention .ko. And Yea, the function isn&#39;t enabled in the kernel by default. Good advice Helmchen

    Rual
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    You can also make a symlink to busybox so you can symply use rmmod:

    # cd /bin# ln -sf busybox rmmod
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    Hi!

    Ok, I enabled unloading moduls in kernel configuration.

    But the following happens:

    # busybox rmmod hello

    rmmod: hello: device or resource busy

    I can&#39;t imagine what could be the reason for this simple module beeing busy?

    Bye, Lothar.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    Lothar,

    I&#39;m asking more than directing. Your init function is not static. Does the kernel lose reference to this module since it is not declaired as static function? Your error says device or resource busy, perhaps the kernel is unsure if the device is in use because it has lost reference to this modue?????

    Again, I&#39;m asking more than I&#39;m suggesting.

    Doug
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    Hi Doug!

    You are right.

    With a static declaration of the init function command rmmod works:-)

    # busybox rmmod hello

    ------------>goodbye, cruel world#

    Thank you, Lothar.