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Re: GPF or QEMU crash when entering Ring 3
Posted: Sun Dec 13, 2015 8:14 am
by osdever
Debugging is working, but it's just freezes when debugger is connected. Neither nexti or next, nor stepi or step are not working.
Re: GPF or QEMU crash when entering Ring 3
Posted: Sun Dec 13, 2015 8:28 am
by osdever
Finally debugging is worked. Using trial&error I find that the code is crashing on iret. But what is causing that?
Re: GPF or QEMU crash when entering Ring 3
Posted: Sun Dec 13, 2015 10:29 am
by Combuster
I've seen a pageful of likely reasons (and less likely reasons that are nonetheless bugs) already. Which ones don't apply?
You can also run the entire set of steps from the Intel manuals by hand and use the actual register/memory values to see what happens exactly.
Re: GPF or QEMU crash when entering Ring 3
Posted: Sun Dec 13, 2015 12:26 pm
by iansjack
Check the items on the stack just before the iret. Are they what you expect them to be? Are they sane? What will iret do with them?
Re: GPF or QEMU crash when entering Ring 3
Posted: Mon Dec 14, 2015 6:59 am
by osdever
iansjack wrote:Check the items on the stack just before the iret. Are they what you expect them to be? Are they sane? What will iret do with them?
How I can do it? GDB is freezing QEMU.