Re: [Qemu-devel] Problems with gdbserver and debugging

[Tace]

Hi,
   I might have similar problems to what you just described. Mine's is
when my kernel module causes several oops, the gdbserver will no
longer break on the breakpoint in virtual machine. I have no idea why
this occurs and Fabrice hasn't reply to my mail yet...

On 12/22/05, Andre Pech <address@hidden> wrote:
> Hi,
>
>  I'm running into problems using qemu to debug a kernel module. My host and
> virtual machine are both x86 running Fedora Core 4. After insmoding the
> module in the virtual machine, starting gdbserver, running gdb on the host
> with the module sections loaded at the right place, and setting a breakpoint
> in the module code, gdb does not always get notified when the code is
> exectuted. After adding debugging statements to qemu, I've experienced the
> following two different failure cases:
>
>  1) The breakpoint is set, but
> translate.c:gen_intermediate_code_internal is not being
> called for the breakpoint address. If I understand things correctly, this
> suggests that the translation block invalidation code which is executed each
> time a breakpoint is set has a problem in it.
>
>  2) translate.c:gen_intermetiate_code_internal is called on
> the address where the breakpoint is set, and gen_debug is called. However,
> gdb does not break into the code. With DEBUG_GDB set, you can see that the
> gdbstub code isn't doing anything in this case, so the gdb process i am
> running is never notified that the breakpoint was hit.
>
>  Both of these cases occur frequently, but not every time. I can run gdb,
> have it break correctly, kill gdb (after disabling the breakpoint and
> continuing), then start gdb again and have it fail.
>
>  I'm going to keep trying to debug this, but I was hoping that someone might
> have some insight into what is going on here. I have not upgraded to qemu
> 0.8.0 yet, but i couldn't find anything that suggested that this would fix
> the problem. Has anyone else run into similar problems?
>
>  Thanks
>  Andre Pech
>
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