Hi
I have tried to solve this problem for a few hours now and I am kinda running out of ideas.
It's my first linux module, so please bear with me if the problem seems really trivial and obvious.
I would really appreciate any help on this issue.
I have attached the source code.
I am trying to install my linux kernel module I am getting the following error:
###############
ERROR:
insmod queryDevice.o
queryDevice.o: init_module: Device or resource busy
Hint: insmod errors can be caused by incorrect module parameters, including invalid IO or IRQ
parameters.
You may find more information in syslog or the output from dmesg
ONCE this error occurs I cannot do cat /proc/devices anymore (doing so results in Segmentation
fault)
lsmod still works (but doesn't list my module that I tried to install)
Also I have to reboot the machine since, doing insmod again just gives the same problem and also the
deviceMajorNum is reduced by everytime (like 254, 253, 252 etc.,) and I cannot trust the insmod
after the first error.
###############
+++++++++++
Linux Version:
# uname -a
Linux dhcp-293-19 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 i686 i386 GNU/Linux
+++++++++
**********
dmesg output: (relevant lines)
After pci_present
After register_chrdev
After hostQueryRegisterSymbols:254
**********
The
"register_chrdev" call in "hostQueryModuleInit" function
messes up things as I found out so far, since commenting it out seems to make "insmod" and "rmmod"
work.
But it seems pretty harmless. Am I missing something ?
I am using a dynamic major number assignment (like the O'Reilly book says)
Thank you very much for your help.
Vijay
#ifndef __KERNEL__
#define __KERNEL__
#endif
#ifndef MODULE
#define MODULE
#endif
// ... OS include files
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioctl.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <asm/uaccess.h>
#include <asm/io.h>
// ... Local declarations
// ... Global variable declarations
// ... Static variable declarations
static int queryMajorNum;
static int queryDevRegistered = 0;
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... Constants
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
MODULE_AUTHOR("Vijay Venkata");
MODULE_SUPPORTED_DEVICE("All Devices on pcibus with a vendorId and deviceId");
MODULE_DESCRIPTION("Provides Query mechanism to get slot information for a"
"given vendorId,deviceId tuple");
MODULE_LICENSE("GPL"); // Just to make the license warning go away on insmod
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... Data Types
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... The Query Device
typedef struct
{
// ... Nothing Device specific
}query_Dev;
// ... The pci device
static struct pci_dev* pPciDev = NULL;
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/*
;
; .FUNCTION:
;
; .NOTES:
;
*/
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//static
void
hostQueryRegisterSymbols
(
void
)
{
EXPORT_NO_SYMBOLS;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... Device Functions
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/*
;
; .FUNCTION:
;
; .NOTES:
;
*/
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//static
int
queryDevice_open
(
struct inode *inode,
struct file *filp
)
{
// ... Do nothing
return 0;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/*
;
; .FUNCTION:
;
; .NOTES:
;
*/
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//static
int
queryDevice_close
(
struct inode *inode,
struct file *filp
)
{
// ... Do nothing
return 0;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... Device File Operations
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... The file operations on this device
struct file_operations queryDevice_fops =
{
open: queryDevice_open,
release: queryDevice_close,
owner: THIS_MODULE,
};
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... Module Entry/Exit Points
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/*
;
; .FUNCTION:
;
; .NOTES:
;
*/
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
int
hostQueryModuleInit
(
void
)
{
if (!pci_present ())
{
printk
(
KERN_WARNING "%s.%d::No pci... Aborting.\n",
__FILE__,
__LINE__
);
return -1;
}
printk
(
KERN_INFO "After pci_present\n"
);
// ... Get dynamic major number from kernel
queryMajorNum = register_chrdev (0, "queryd", &queryDevice_fops);
printk
(
KERN_INFO "After register_chrdev\n"
);
if (queryMajorNum < 0)
{
printk
(
KERN_ERR "%s.%d::register_chrdev(%s) returned (%d)...\n",
__FILE__,
__LINE__,
"queryd",
queryMajorNum
);
return queryMajorNum;
}
queryDevRegistered = 1;
//hostQueryRegisterSymbols ();
printk
(
KERN_INFO "After hostQueryRegisterSymbols:%u \n",
queryMajorNum
);
return queryMajorNum;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/*
;
; .FUNCTION:
;
; .NOTES:
;
*/
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void
hostQueryModuleUninit
(
void
)
{
if (queryDevRegistered)
{
printk
(
KERN_INFO "%s.%d::Unregistering host query Device ...\n",
__FILE__,
__LINE__
);
queryDevRegistered = 0;
unregister_chrdev (queryMajorNum, "queryd");
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... Define the Entry/Exit points for this module
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
module_init(hostQueryModuleInit);
module_exit(hostQueryModuleUninit);
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ... end of file
