Windows debugger -> gdbserver throws up a weird error

Windows debugger -> gdbserver throws up a weird error

[Dilip Ranganathan]

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Recently Microsoft advertised
<https://learn.microsoft.com/en-us/windows-hardware/drivers/debugger/linux-live-remote-process-debugging#attach-gdbserver-to-the-selected-process>
their ability to connect their Windbg debugger to gdbserver running on a
remote machine through WSL. I have been trying to experiment with that. I
ssh into a linux machine through WSL. When I try to connect using Windbg,
the connection is successfully established but gdbserver dies with:

../../gdbserver/regcache.cc:271: A problem internal to GDBserver has been
detected.
Unknown register ymm0h requested

A bit of searching on the interwebs revealed this to be a problem with a
particular version of gdbserver (< 7.0) but I am running the latest (14.2),
so it probably isn't a version issue.

Interestingly I am successfully able to connect from yet another linux
machine from gdb to gdbserver just fine.

Any ideas on why or how this might have happened?

Re: Windows debugger -> gdbserver throws up a weird error

[Simon Marchi]

On 3/6/24 20:58, Dilip Ranganathan via Gdb wrote:
> Recently Microsoft advertised
> <https://learn.microsoft.com/en-us/windows-hardware/drivers/debugger/linux-live-remote-process-debugging#attach-gdbserver-to-the-selected-process>
> their ability to connect their Windbg debugger to gdbserver running on a
> remote machine through WSL. I have been trying to experiment with that. I
> ssh into a linux machine through WSL. When I try to connect using Windbg,
> the connection is successfully established but gdbserver dies with:
> 
> ../../gdbserver/regcache.cc:271: A problem internal to GDBserver has been
> detected.
> Unknown register ymm0h requested
> 
> A bit of searching on the interwebs revealed this to be a problem with a
> particular version of gdbserver (< 7.0) but I am running the latest (14.2),
> so it probably isn't a version issue.
> 
> Interestingly I am successfully able to connect from yet another linux
> machine from gdb to gdbserver just fine.
> 
> Any ideas on why or how this might have happened?

Windbg must do something different than GDB, causing GDBserver to take a
different (and obviously less tested) path.

Can you run gdbserver with `--debug=remote`?  It will show all the
communication between it and GDB / Windbg.  For instance:

    $ gdbserver --debug=remote localhost:1234 python3

Do a run with GDB and one with Windbg.  You can open a bug at
https://sourceware.org/bugzilla and attach files with the output of both
runs there.

Thanks,

Simon