[Lguest] probing the guest os kernel code ?

[Rusty Russell]

On Wed, 25 Nov 2009 06:01:04 pm dylan wrote:
> I want to collect informations about guest os,so i probing the guest os 
> code using kprobe.
> First, I run a guest os(linux-2.6.31) using lguest, and insmod the 
> fellow module--the code is as follows.
> 
> @%@%> insmod /home/lguest_kprobe_example.ko
> [ 11.592410] Planted kprobe at c0163430
> 
> Results is right above,but when I run command "dmeg" to view the print 
> information,the results are fellows:
> 
> @%@%> dmesg
> [ 85.056197] pre_handler1: p->addr = 0xc0163430, ip = c0163431, flags = 
> 0x286
> [ 85.056249] pre_handler2: p->symbol_name=do_fork, p->opcode=85
> lguest: Bad address 0xc3a37c34

I'm not surprised.  We don't let the guest set debug registers or such.  No
doubt the breakpoint instruction jumps to hyperspace.

I've cc'd some kprobes people, in case they want to add debug register
support to lguest :)

Cheers,
Rusty.