Re: [PATCH] gdbstub: use 0 ("any process") on packets with no PID

[Ilya Leoshkevich <iii@linux.ibm.com>]

On Tue, 2023-08-01 at 12:37 -0300, Matheus Tavares Bernardino wrote:
> Previously, qemu-user would always report PID 1 to GDB. This was
> changed
> at dc14a7a6e9 (gdbstub: Report the actual qemu-user pid, 2023-06-30),
> but read_thread_id() still considers GDB packets with "no PID" as
> "PID
> 1", which is not the qemu-user PID. Fix that by parsing "no PID" as
> "0",
> which the GDB Remote Protocol defines as "any process".
> 
> Note that this should have no effect for system emulation as, in this
> case, gdb_create_default_process() will assign PID 1 for the first
> process and that is what the gdbstub uses for GDB requests with no
> PID,
> or PID 0.
> 
> This issue was found with hexagon-lldb, which sends a "Hq" packet
> with
> only the thread-id, but no process-id, leading to the invalid usage
> of
> "PID 1" by qemu-hexagon and a subsequent "E22" reply.

Did you mean "Hg"?

> Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
> ---
>  gdbstub/gdbstub.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

The change looks good to me.
Thanks for looking into this and sorry for the breakage.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>