Re: problem in initilisation

Ravi Kumar <ravivsn@rocsys.com> · Tue, 20 Apr 2004 15:09:41 +0530

Thanks to Suvidh, Mandeep, MohanLal and Megharaj for helping me out.

When I changed the device name to have "eth" in it, it got identified as 
ethernet device.

-Ravi

Suvidh Mathur wrote:

ya true, my mistake. its just strncmp, so string "eth" anywhere
in the name should suffice.

19/04/2004 3:03 PM
To: "Suvidh Mathur" <Suvidh.Mathur@lntinfotech.com>, "Ravi Kumar"
<ravivsn@rocsys.com>
cc: <kernelnewbies@nl.linux.org>
From: "Mandeep Singh Sandhu" <mandeep_sandhu@infosys.com>
Subject: RE: problem in initilisation

i don't think so, i have named my device "mss-eth"
and it works fine!

- /dev/mandeep

-----Original Message-----
From: kernelnewbies-bounce@nl.linux.org
[mailto:kernelnewbies-bounce@nl.linux.org]On Behalf Of Suvidh Mathur
Sent: Monday, April 19, 2004 2:22 PM
To: Ravi Kumar
Cc: kernelnewbies@nl.linux.org
Subject: Re: problem in initilisation

Ravi,

I dont know about the divert code, but it seems that ethernet device
identification is done on the first 3 letters of the device name, i.e.
your device must be named "eth"xxx. Check alloc_divert_blk in dv.c
HTH

19/04/2004 1:18 PM
To: Suvidh Mathur <Suvidh.Mathur@lntinfotech.com>
cc: kernelnewbies@nl.linux.org
From: Ravi Kumar <ravivsn@rocsys.com>
Subject: Re: problem in initilisation

Suvid,
Thanks for the information. Now, I allocated memory and the problem
seems to be with identification as ethernet device.

dmesg shows the below info

divert: not allocating divert_blk for non-ethernet device testdev0
Unable to handle kernel paging request at virtual address 0180040e
printing eip:
c01f64a4
*pde = 00000000
Oops: 0000
testdriver i810_audio ac97_codec soundcore mousedev input i810 agpgart
autofs
CPU:    0
EIP:    0010:[<c01f64a4>]    Tainted: PF
EFLAGS: 00210296

EIP is at __rta_fill [kernel] 0x64 (2.4.18-14)
eax: 0000000a   ebx: 00000004   ecx: 00000001   edx: c7e21c60
esi: 0180040e   edi: c187b060   ebp: 00000008   esp: c676fe1c
ds: 0018   es: 0018   ss: 0018
Process insmod (pid: 1056, stackpage=c676f000)
Stack: 00000000 c0154a30 00000001 0000000a 00000000 c7ba4a00 c034192d
c7e21c60
      c01f6a6f c7e21c60 0000000a 00000004 0180040e c0341928 00000f10
      c0341960
      00000010 c187b000 000005dc c7e21c60 c7ba4a00 00000010 ffffffff
      c01f6ced
      Call Trace: [<c0154a30>] alloc_inode [kernel] 0xa0 (0xc676fe20))
      [<c01f6a6f>] rtnetlink_fill_ifinfo [kernel] 0x37f (0xc676fe3c))
      [<c01f6ced>] rtmsg_ifinfo [kernel] 0x5d (0xc676fe78))
      [<c01f6f7f>] rtnetlink_event [kernel] 0x2f (0xc676fea4))
      [<c012613d>] notifier_call_chain [kernel] 0x2d (0xc676feb4))
      [<c01f2585>] register_netdevice [kernel] 0x115 (0xc676fed0))
      [<c8e5d2f4>] init_module [testdriver] 0x130 (0xc676feec))
      [<c8e5d526>] .rodata [testdriver] 0x86 (0xc676fef4))
      [<c011bf79>] sys_init_module [kernel] 0x4d9 (0xc676ff1c))
      [<c8e5d060>] test_open [testdriver] 0x0 (0xc676ff20))
      [<c8e5d060>] test_open [testdriver] 0x0 (0xc676ff58))
      [<c010910f>] system_call [kernel] 0x33 (0xc676ffc0))

Code: f3 a5 f6 c3 02 74 02 66 a5 f6 c3 01 74 01 a4 8b 5c 24 10 8b

Thanks in advance,
-Ravi

Suvidh Mathur wrote:

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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