copy_to_user

[Dave Hylands]

Hi Nilesh.

On Thu, Dec 23, 2010 at 11:59 PM, Nilesh Tayade
<nilesh.tayade at netscout.com> wrote:
...snip...
> I tried it, and it seems adding mutex_init() works as Mukti mentioned. I
> did get a kernel oops before (but no segfault). After adding
> mutex_init() there is no oops/segfault. The code, however, is reading
> the garbage, that needs to be fixed.

	char n[20];
	short a = *((short *)&n[0]);
	short b = *((short *)&n[2]);
	short c = *((short *)&n[4]);

This sets a b and c to have essentially random values.

		nbytes = read( fd, n, 40);

This causes the value of n to change. However, the values of a, b, and
c retain the same random values you assigned them above.

		printf( "\r a = %d \n ", a);
		printf("\r b = %d \n",b);
		printf("\r c = %d \n",c);

This prints the random values of a, b, and c rather than printing thee
values of n that you read in.

Dave Hylands