Re: copy_to_user

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Nilesh.

On Thu, Dec 23, 2010 at 11:59 PM, Nilesh Tayade
<nilesh.tayade@xxxxxxxxxxxx> 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

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@xxxxxxxxxxxxxxxxx
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


[Index of Archives]     [Newbies FAQ]     [Linux Kernel Mentors]     [Linux Kernel Development]     [IETF Annouce]     [Git]     [Networking]     [Security]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux SCSI]     [Linux ACPI]
  Powered by Linux