Re: [Xen-devel] gdbserver-xen / gdb crashing domU

["Jonathan M. McCune" <jonmccune@xxxxxxx>]

Hi Kip,

Thanks for your quick response.  Unfortunately, in the experiment I 
described in my first post, I did have domu_debug=y in xen/Rules.mk.  I 
rebuilt and reinstalled xen after a `make clean` in the xen subdir just 
to be sure it would have picked up the change.
Any other ideas?

Thanks,
-Jon

Kip Macy wrote:

> domu_debug must be enabled in xen's Rules.mk <http://Rules.mk>, otherwise
> the int3 gets passed onto the OS which will cause it to crash as it isn't
> expecting to see a debug trap in ring 0 (unless of course you have a
> debugger compiled into the kernel itself).
>
> Just re-compile and then pass -p (pause) to xm create followed by an attach
> with gdbserver-xen.
>
> -Kip
>
> On 9/27/05, Jonathan M. McCune <jonmccune@xxxxxxx> wrote:
>  
>
> > Hello,
> >
> > I'm trying to use gdb and gdbserver-xen to walk through the instructions
> > executed when starting up a domU kernel. We are using the current
> > xen-unstable (linux-2.6.12-xenU). I have followed the instructions in
> > tools/debugger/gdb/ and I am able to successfully attach to a running
> > domU kernel. I have compiled the domU kernel with debug options as
> > described in tools/debugger/gdb/README. After attaching to the running
> > domU kernel, I observe the following behavior:
> >
> > Issuing the gdb commands 'step', 'stepi', 'next', and 'nexti' when the
> > domU kernel is initially paused all crash the domU kernel silently
> > (i.e., the state of said domU goes to 'c' if you issue an `xm list` in
> > dom0). 'continue' causes the domU kernel to boot up correctly.
> >
> > All the breakpoints I've tried setting so far (setting the breakpoints
> > before issuing the 'continue' in gdb) cause the domU kernel to panic
> > when the function at which the breakpoint is set gets run. Functions
> > I've tried setting breakpoints for include dup_task_struct, queue_work,
> > scheduler_tick, and activate_task.
> >
> > Is it possible to step through the domU kernel code as it is booted in
> > Xen?
> >
> > Thanks,
> > -Jon
> >
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> >
> >
> >
> >
> >    
>

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