The following code fails when i try to register the v4l device and a
'Segmentation fault' message occurs. I tested my code using both linux
2.4.19 and linux 2.4.20. The video_device structure seems to be filled
properly, i don't know what is wrong...
Below the source code there's also the kernel message.
Essentially this is the code:
/* Main structure */
struct my_device {
struct video_device v4l;
.....
.....;
};
int my_probe(..., ...)
{
...
camera = (struct my_device*)
kmalloc(sizeof(struct my_device), GFP_KERNEL);
strcpy(camera->v4l.name, "My device");
camera->v4l.type = MY_CAP_TYPE;
camera->v4l.hardware = MY_VID_HARDWARE;
camera->v4l.fops = &my_fops; /* new interface */
camera->v4l.priv = (void*)camera;
camera->v4l.minor = -1; /* or whatever */
printk(KERN_INFO "My device: Registering...");
/* This function never returns...why? */
err = video_register_device(&camera->v4l,
VFL_TYPE_GRABBER,
-1); /* or whatever */
/* The code below is never reached */
if (err)
printk(KERN_ERR "Video register failed.");
else
printk(KERN_INFO "My device registered. ");
...
}
*Kernel error message*
My device: Registering...
Unable to handle kernel paging request at virtual address 00050338
printing eip:
00050338
*pde = 00000000
Oops: 0000
CPU: 0
EIP: 0010:[<00050338>] Not tainted
EFLAGS: 00010202
eax: 00050338 ebx: 00000001 ecx: d1aee1e0 edx: d1aee280
esi: 00000000 edi: c8e91c00 ebp: 00000004 esp: c46b1e40
ds: 0018 es: 0018 ss: 0018
Process insmod (pid: 1482, stackpage=c46b1000)
Stack: d1aedafb c8e91c00 d1aee08c c02fa889 00000246 00000049 c46b1e98 c8e91c00
d2443c9d d2443e0c c46b1e98 d2443167 c8e91c00 00000000 ffffffff c0299e10
c0299fd0 00000000 000001d2 d2443458 d2443ea0 d2443ebc c1321b60 c02081ae
Call Trace: [<d1aedafb>] [<d1aee08c>] [<d2443c9d>] [<d2443e0c>]
[<d2443167>]
[<d2443458>] [<d2443ea0>] [<d2443ebc>] [<c02081ae>] [<d2443458>]
[<c0207e88>]
[<c0207e5c>] [<c020764e>] [<d2443ea0>] [<c0207615>] [<d2443350>]
[<d2443ea0>]
[<c011a785>] [<d2443d7c>] [<d2441060>] [<c010881b>]
Code: Bad EIP value.
