On Thu, Oct 6, 2011 at 9:42 PM, rohan puri <rohan.puri15@xxxxxxxxx> wrote:
Hi Vaibhav,On Fri, Oct 7, 2011 at 4:13 AM, Vaibhav Jain <vjoss197@xxxxxxxxx> wrote:
_______________________________________________On Thu, Oct 6, 2011 at 11:28 AM, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote:
Hi...
Probably this could also due to mmap NULL dereferencing protection (at
On Thu, Oct 6, 2011 at 02:34, Vaibhav Jain <vjoss197@xxxxxxxxx> wrote:
> Hi,
>
> I am trying to run a program that scans memory from a given physical address
> using /dev/mem.
> It uses mmap to map physical address from /dev/mem. So to start with I used
> /proc/iomem to look up the
> physical memory mapping and found the address 00010000 to be the starting
> address for System ram. But whenever I
> provide this address to the program it throws an error of "Operation not
> permitted".
least that's how I name it :) )
By default, the lowest 65536 byte (10000 in hex) is protected from
mapping etc. It practically render such null dererefencing useless.
--
regards,
Mulyadi Santosa
Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
Hi,I tried the same with other addresses (greater than 0x10000 ) also but it is throwing the same error.Is there a way to get over this ?ThanksVaibhav Jain
Kernelnewbies mailing list
Kernelnewbies@xxxxxxxxxxxxxxxxx
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
This is how it can be done. Refer link http://www.theknotter.net/system-memory-dumps-on-linux/
I have attached the modified code which disables the socket creation part and dumps the output in a file.
Regards,
Rohan Puri
Thanks Rohan for the code but I already have a code that reads memory using /dev/mem and mmap.
Only difference is I have to manually change the starting address in program. The problem is whenver I give
any System RAM address the mmap call fails with 'Operation not permitted'. I googled a little and found that normally
this operation is not allowed and the kernel has to be compiled with CONFIG_STRICT_DEVMEM disabled to read any memory
location in this way. I also found out about the boot option 'strict-devmem =0'. I tried both these options but none of them seems to working.
So I am trying to figure out if there is some other setting that I need to change.
I am doing this on Fedora 15 - 2.6.38 kernel.
Thanks
Vaibhav Jain
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
