Re: Multi-packet gdb server request/response - problem?

Philippe Waroquiers
2013-12-10T21:46:08Z

On Tue, 2013-12-10 at 13:22 +0100, Ivo Raisr wrote:

> My questions are:
> - Is multi-packet request/response supported by gdb?
> - In other words, is that gdb's behaviour intentional?
> - If yes, then why it cannot handle multi-packet response?
> - If no, then is that a bug?
Valgrind gdbserver implements (only) the all-stop mode.

To my knowledge, with that mode, the principle is that GDB should
send one command (such as "s" step), and then should wait for the reply.
So, having an "s" packet directly followed by an "m" packet
looks strange to me (at least, I never saw this).

Does this also happen with the gdbserver included in the GDB
distribution ?
(be sure GDB is in all stop mode :
show non-stop
)

When using the Valgrind gdbserver, does the problem also happens
if you first instruct GDB to keep the "ack mode" ?
i.e. first use
set remote noack-packet 0
before launching
target remote | vgdb
In that mode, GDB and Valgrind gdbserver will continue
to have each packet acknowledged using a +.

Philippe

NB: when GDB is set in non stop mode and connected to the Valgrind
gdbserver, it reports that the remote stub does not support
non stop mode, but still continues (and that does not work properly
after).
I am wondering why the choice between all-stop and non-stop is
then not automatically "auto choosed/probed" by GDB ?