Re: problem in initilisation

["Suvidh Mathur" <Suvidh.Mathur@lntinfotech.com>]

Hi,
At first glance, I could not find where you have allocated your netdevice
structure. The struct test_struct contains a pointer to net_device, but
where are you allocating it?

Regards,



19/04/2004 10:53 AM
To: kernelnewbies@nl.linux.org
cc:
From: Ravi Kumar <ravivsn@rocsys.com>
Subject: problem in initilisation



HI,
I wrote one character device which should create network device. When I
do insmod it gave a segmentation fault and lsmod shows initializing.

A dmesg shows:

EIP is at init_module [testdriver] 0xa6 (2.4.18-14)
eax: 00000000   ebx: ffffffea   ecx: c05b6000   edx: c8e7f4d3
esi: 00000000   edi: 00000000   ebp: c672df18   esp: c672df00
ds: 0018   es: 0018   ss: 0018
Process insmod (pid: 9922, stackpage=c672d000)
Stack: 00200206 ffffffff 00002f3f c05b6940 00000000 00000000 c8e7f000
c011bf79
       c8e7f060 08075228 00000908 00000000 080756f4 0000052c 00000060
       00000060
       0000000a c05b6c40 c6231000 c6e7e000 00000060 c8def000 c8e7f060
       00000968
       Call Trace: [<c011bf79>] sys_init_module [kernel] 0x4d9
(0xc672df1c))
       [<c8e7f060>] test_open [testdriver] 0x0 (0xc672df20))
       [<c8e7f060>] test_open [testdriver] 0x0 (0xc672df58))
       [<c010910f>] system_call [kernel] 0x33 (0xc672dfc0))


Code: c7 40 34 fe f0 e7 c8 83 ec 08 68 d4 f4 e7 c8 8b 45 f4 ff 30


I am attaching the code, pls help me to solve this problem.
Thanks a lot,
-Ravi

#ifndef __KERNEL__
#   define __KERNEL__
#endif

#ifndef MODULE
#  define MODULE
#endif

#define DEVNAME "testdev"

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

#include <linux/netdevice.h>
#include <linux/if_ether.h>



int test_open(struct inode *,struct file *);
int test_release(struct inode *,struct file*);


struct test_struct{
struct net_device *dev;
char name[IFNAMSIZ];
};



struct file_operations test_fop={
llseek:     NULL,
read:       NULL,
write:      NULL,
ioctl:      NULL,
open:       test_open,
release:    test_release,
};



int test_open(struct inode *inode, struct file *filep)
{
       MOD_INC_USE_COUNT;
       return 0;
}

int test_release(struct inode *inode, struct file *filep)
{
       MOD_DEC_USE_COUNT;
       return 0;
}

int testdev_open(struct net_device *dev)
{
       MOD_INC_USE_COUNT;
       return 0;
}

int testdev_close(struct net_device *dev)
{
       unregister_netdev(dev);
       MOD_DEC_USE_COUNT;
       return 0;
}

static int test_init_dev(struct net_device *dev)
{
       struct test_struct *c;

       dev->priv = kmalloc(sizeof(struct net_device),GFP_KERNEL);
       if(!dev->priv)
       {
  printk(KERN_ERR "out of memory while allocating to dev->priv\n");
  return -ENOMEM;
       }
       c = (struct test_struct *)dev->priv;
       if(!c)
  return -ENODEV;

 memset(c,0,sizeof(struct test_struct));
 c->dev = dev;
 ether_setup(dev);

       dev->open  = testdev_open;
       dev->stop  = testdev_close;
       dev->mtu   = ETH_DATA_LEN;
       dev_init_buffers(dev);
       return 0;
}


int init_module(void)
{
       int result,i;

        struct test_struct *pTestStruct;
        result = register_chrdev(16,"test",&test_fop);
        if( result < 0 ){
  printk(KERN_WARNING "test: cant get major\n");
  return result;
 }
 pTestStruct = (struct test_struct *)kmalloc(sizeof( struct
  test_struct),GFP_KERNEL);
       if(!pTestStruct)
       {
  printk(KERN_ERR "failed to allocate memory\n");
  return -ENOMEM;
       }

        memset((void *)pTestStruct,0,sizeof(pTestStruct));
        sprintf(pTestStruct->name, DEVNAME);
        //pTestStruct->dev->priv = pTestStruct;
        pTestStruct->dev->init = test_init_dev;

       i = dev_alloc_name(pTestStruct->dev,"testdev%d");
       if(i < 0 )
       {
  printk(KERN_ERR "cant allocate device\n");
  return -ENODEV;
       }
       i = register_netdevice((pTestStruct->dev));
       if( i < 0 )
  printk(KERN_ERR "register netdevice failed\n");

 return 0;
 }

void cleanup_module(void)
{

 unregister_chrdev(16,"test");
 }







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