Bdtjtk

I was writing a sample request_irq code

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/interrupt.h>

#include <linux/delay.h>



MODULE_LICENSE("GPL");

int irq = 1;

int dev = 0xaa;



static irqreturn_t keyboard_handler(int irq, void *dev)

{

    static int counter = 0;

    pr_info("Keyboard Counter:%dn", counter++);

    return IRQ_NONE;

}



static int test_interrupt_init(void)

{

    pr_info("%s: In initn", __func__);

    return request_irq(irq, keyboard_handler, IRQF_SHARED,

            "my_keyboard_handler", &dev);

}



static void test_interrupt_exit(void)

{

    pr_info("%s: In exitn", __func__);

    synchronize_irq(irq);

    free_irq(irq, &dev);

}



module_init(test_interrupt_init);

module_exit(test_interrupt_exit);

While removing this module, I am getting the error:

rmmod: ERROR: ../libkmod/libkmod-module.c:769 kmod_module_remove_module() could not remove 'interrupt': Device or resource busy

rmmod: ERROR: could not remove module interrupt: Device or resource busy

Why I am getting this error, as I am using IRQF_SHARED and passed the dev parameter in request_irq and free_irq

Update: From the dmesg, I don't see any printk on rmmod
Added dmesg logs:

[ 4007.223281] Keyboard Counter:884

[ 4007.560846] Keyboard Counter:885

[ 4007.670339] Keyboard Counter:886

[ 4008.240139] Keyboard Counter:887

[ 4008.275412] Keyboard Counter:888

[ 4008.359338] Keyboard Counter:889

[ 4008.425101] Keyboard Counter:890

[ 4008.433026] Keyboard Counter:891

[ 4008.501763] Keyboard Counter:892

[ 4008.579201] Keyboard Counter:893

[ 4008.653335] Keyboard Counter:894

[ 4008.682862] Keyboard Counter:895

[ 4008.733950] Keyboard Counter:896



$ cat /proc/interrupts 

           CPU0       CPU1       CPU2       CPU3       

  0:          1          0          0          0   IO-APIC   2-edge      timer

  1:        449          0          0        707   IO-APIC   1-edge      i8042, my_keyboard_handler

  6:          0          0          2          0   IO-APIC   6-edge      floppy

  7:          0          0          0          0   IO-APIC   7-edge      parport0

  8:          0          1          0          0   IO-APIC   8-edge      rtc0

  9:          0          0          0          0   IO-APIC   9-fasteoi   acpi

Try this:

static int irq = 1, dev = 0xaa;

You need to give permission to variable irq and then call module_param() like below

module_param(irq, int, S_IRUGO);

sample code

MODULE_LICENSE("GPL");

static int irq = 1,  dev = 0xaa, counter = 0;

module_param(irq, int, S_IRUGO); /* give the permission to user space variable */



static irqreturn_t keyboard_handler(int irq, void *dev)

{

        pr_info("Keyboard Counter:%dn", counter++);

        return IRQ_NONE;

}

/* registering irq */

static int test_interrupt_init(void)

{

        pr_info("%s: In initn", __func__);

        if(request_irq(irq, keyboard_handler, IRQF_SHARED,"my_keyboard_handler", &dev)) {

                return -1;

        }

        else

        {

                pr_info("success n");

                return 0;

        }

}



static void test_interrupt_exit(void)

{

        pr_info("%s: In exitn", __func__);

        synchronize_irq(irq); /* synchronize interrupt */

        free_irq(irq, &dev);

}



module_init(test_interrupt_init);

module_exit(test_interrupt_exit);