Re: Mapping to 0x0

[Kyle Moffett]

On Feb 24, 2006, at 06:37:21, Michael Buesch wrote:
> I am playing around with it. I did the attached code. It is a  
> usermode program, which tries to map NULL, and a kernel module,  
> which calls a NULL pointer. The file badcode.bin contains an i386  
> ud2 instruction. When loading the kernel module, while the usermode  
> program is executing, I get the usual NULL pointer dereference oops:

You need to trigger the null pointer dereference from within the  
userspace program that maps NULL.  The reason your test doesn't do  
anything is that it is the insmod tool whose address space gets used,  
as opposed to your nulltest program.

Cheers,
Kyle Moffett

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