gdb tcp connection closing

gdb tcp connection closing

[Bill Morgan]

I'm trying to write a GDB stub for an embedded application

For some reason the GDB host is closing the TCP connection after it
requests qOffsets, and the stub sends an empty reply.

Is that expected?

Here is the entire conversation:

Host:
.+$qSupported:multiprocess+;swbreak+;hwbreak+;qRelocInsn+;fork-events+;vfork-events+;exec-events+;vContSupported+;QThreadEvents+;no-resumed+#df

Target: +$PacketSize=3fff;QPassSignals+;qXfer:features:read+#8f

Host: +$vMustReplyEmpty#3a

Target: +$#00

Host: +$Hg0#df

Target: +$OK#9a

Host: +$qXfer:features:read:target.xml:0,fff#7d

Target: +$l<target><architecture>arm</architecture></target>#06

Host: +$qTStatus#49

Target: +$#00

Host: +$?#3f

Target: +$T050b:0*"00;0d:e07f2030;0f:10533060;thread:9#24

Host: +$qfThreadInfo#bb

Target: +$m9#a6

Host: +$qsThreadInfo#c8

Target: +$me#d2

Host: +$qsThreadInfo#c8

Target: +$mf#d3

Host: +$qsThreadInfo#c8

Target: +$m13#d1

Host: +$qsThreadInfo#c8

Target: +$l#6c

Host: +$qAttached#8f

Target: +$1#31

Host: +$Hc-1#09

Target: +$OK#9a

Host: +$qOffsets#4b

Target: +$#00

Host: +

Host closes connection

Re: gdb tcp connection closing

[Christo]

On Thu, 2018-09-20 at 17:48 -0500, Bill Morgan wrote:
> I'm trying to write a GDB stub for an embedded application
> 
> For some reason the GDB host is closing the TCP connection after it
> requests qOffsets, and the stub sends an empty reply.
> 
> Is that expected?

Have you activated the debug remote option in gdb (set debug remote 1)? This is sometimes useful
in pinpointing rsp problems.

Re: gdb tcp connection closing

[Bill Morgan]

On Thu, Sep 20, 2018 at 11:49 PM Christo <christo.crause@gmail.com> wrote:

> On Thu, 2018-09-20 at 17:48 -0500, Bill Morgan wrote:
> > I'm trying to write a GDB stub for an embedded application
> >
> > For some reason the GDB host is closing the TCP connection after it
> > requests qOffsets, and the stub sends an empty reply.
> >
> > Is that expected?
>
> Have you activated the debug remote option in gdb (set debug remote 1)?
> This is sometimes useful
> in pinpointing rsp problems.
>

Thanks. It is saying the remote register packet is badly formatted.

Which part of the packet is wrong?

gdb.error: Remote register badly formatted:
T050b:00000000;0d:d87e2030;0f:d4523060;thread:9

signal: 05
reg 0b (r11):00000000
reg 0d (sp):d87e2030
reg 0f: (pc): d4523060
thread: 9

full output:

Sending packet:
$qSupported:multiprocess+;swbreak+;hwbreak+;qRelocInsn+;fork-events+;vfork-events+;exec-events+;vContSupported+;QThreadEvents+;no-resumed+#df...Ack
Packet received: PacketSize=3fff;QPassSignals+;qXfer:features:read+
Packet qSupported (supported-packets) is supported
Sending packet: $vMustReplyEmpty#3a...Ack
Packet received:
Sending packet: $Hg0#df...Ack
Packet received: OK
Sending packet: $qXfer:features:read:target.xml:0,fff#7d...Ack
Packet received: l<target><architecture>arm</architecture></target>
Sending packet: $qTStatus#49...Ack
Packet received:
Packet qTStatus (trace-status) is NOT supported
Sending packet: $?#3f...Ack
Packet received: T050b:00000000;0d:d87e2030;0f:d4523060;thread:9
Sending packet: $qfThreadInfo#bb...Ack
Packet received: m9
Sending packet: $qsThreadInfo#c8...Ack
Packet received: me
Sending packet: $qsThreadInfo#c8...Ack
Packet received: mf
Sending packet: $qsThreadInfo#c8...Ack
Packet received: m13
Sending packet: $qsThreadInfo#c8...Ack
Packet received: l
Sending packet: $qAttached#8f...Ack
Packet received: 1
Packet qAttached (query-attached) is supported
Sending packet: $Hc-1#09...Ack
Packet received: OK
Sending packet: $qOffsets#4b...Ack
Packet received:
Traceback (most recent call last):
  File "gdbinit_hosted_apps.py", line 92, in <module>
    gdb.execute( 'target remote ' + target_path )
gdb.error: Remote register badly formatted:
T050b:00000000;0d:d87e2030;0f:d4523060;thread:9
here:
(gdb)

Re: gdb tcp connection closing

[Bill Morgan]

On Fri, Sep 21, 2018 at 7:56 AM Bill Morgan <arthurwilliammorgan@gmail.com>
wrote:

>
> On Thu, Sep 20, 2018 at 11:49 PM Christo <christo.crause@gmail.com> wrote:
>
>> On Thu, 2018-09-20 at 17:48 -0500, Bill Morgan wrote:
>> > I'm trying to write a GDB stub for an embedded application
>> >
>> > For some reason the GDB host is closing the TCP connection after it
>> > requests qOffsets, and the stub sends an empty reply.
>> >
>> > Is that expected?
>>
>> Have you activated the debug remote option in gdb (set debug remote 1)?
>> This is sometimes useful
>> in pinpointing rsp problems.
>>
>
> Thanks. It is saying the remote register packet is badly formatted.
>
> Which part of the packet is wrong?
>
> gdb.error: Remote register badly formatted:
> T050b:00000000;0d:d87e2030;0f:d4523060;thread:9
>

I was missing the trailing semicolon ';'