Kernel OOPS[filesystem programming]

Kernel OOPS[filesystem programming]

[Jeba Anandhan A]

i have written kernel program to access the data
structure of particular inode.

#include<linux/kernel.h>
#include<linux/module.h>
#include<linux/fs.h>
                                                      
                                                      
              
                                                      
                                                      
              
static struct inode *my_inode;
static unsigned long inode_no;
int init_module(void){
printk("inode module inserted\n");
inode_no=1304012;
printk("inode no=%d",inode_no);
my_inode->i_ino=inode_no; // it creates segmentation
//fault why so..
return 0;
}
                                                      
                                                      
              
void cleanup_module(void){
}
                                                      
                                                      
              
when i insert the module ,kernel got OOPS.
~
<1>Unable to handle kernel NULL pointer dereference at
virtual address 00000028
 printing eip:
d09c80a1
*pde = 0841b067
*pte = 00000000
Oops: 0002
inodetraversal1 inodetraversal i810_audio ac97_codec
soundcore parport_pc lp parport autofs 3c59x floppy sg
microcode ide-scsi scsi_mod ide-cd cdrom keybdev h
CPU:    0
EIP:    0060:[<d09c80a1>]    Tainted: P
EFLAGS: 00210282
 
EIP is at init_module [inodetraversal1] 0x41
(2.4.22-1.2115.nptl)
eax: 00000000   ebx: c0349124   ecx: 00000001   edx:
0013e5cc
esi: 00000000   edi: 00000000   ebp: c4123f10   esp:
c4123f08
ds: 0068   es: 0068   ss: 0068
Process insmod (pid: 7866, stackpage=c4123000)
Stack: c0349124 00000000 d09c8000 c011ed74 c03badb4
00000001 d09c8000 00000000
       08ea51c3 d09c8060 00000003 000000d3 00000060
0000000f c89855c0 ccd26000
       cbbb4000 d09ca000 00000060 d09ad000 d09c8060
0000037c 00000000 00000000
Call Trace:   [<c011ed74>] sys_init_module [kernel]
0x584 (0xc4123f14)
[<d09c8060>] init_module [inodetraversal1] 0x0
(0xc4123f2c)
[<d09c8060>] init_module [inodetraversal1] 0x0
(0xc4123f58)
[<c0109b9f>] system_call [kernel] 0x33 (0xc4123fc0)
 
 
Code: 89 50 28 b8 00 00 00 00 c9 c3 55 89 e5 c9 c3 69
6e 6f 64 65
  
whatz problem with my program.how to rectify.?
jeba

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Re: Kernel OOPS[filesystem programming]

[David Ford]

[-- Attachment #1: Type: text/plain, Size: 578 bytes --]

What is *my_inode set to?

Jeba Anandhan A wrote:

>i have written kernel program to access the data
>structure of particular inode.
>
>#include<linux/kernel.h>
>#include<linux/module.h>
>#include<linux/fs.h>
>              
>static struct inode *my_inode;
>static unsigned long inode_no;
>  
>
>int init_module(void){
>  printk("inode module inserted\n");
>  inode_no=1304012;
>  printk("inode no=%d",inode_no);
>  my_inode->i_ino=inode_no; // it creates segmentation
>                            //fault why so..
>return 0;
>}
>              
>void cleanup_module(void){
>}
>

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