kgdb debugging

[alan yang]

Could people shed some light how to get remote debugging going, must
be something that i overlooked, really appreciate.

Two FreeBSD7 systems, target and development, connected with null
modem cable on each's COM1.

step 1)
	-  rebuild kernel with following options:
		options		DDB
		options		KDB
		options		GDB

		makeoptions	DEBUG=-g

step 2)
	-  from development system
		cd to /usr/src/sys/i386/comiple/MYKERNEL
		kgdb -r /dev/cuad0 kernel.debug
		
		it displays the following:
		Switching to remote protocol
		Ignoring packet error, continuing
			.........
		Couldn't establish connection to remote target
		Malformed response to offset query, timeout
	
step 3)
	-  from targetsystem:
		1.  Ctrl + Alt + Esc to go into db
		2.  from db> type gdb
		3.  it displays: "The remote GDB backend could not be selected"

	

On Mon, Oct 6, 2008 at 5:12 PM, alan yang <alancyang at gmail.com> wrote:
> the problem is, when entering gdb from db as described in the following:
> --
> Enter ing gdb from ddb
> In FreeBSD you can build a kernel with support for both ddb and gdb.
> You can then
> change backwards and forwards between them. For example, if you're in
> ddb, you can
> go to gdb like this:
> db> gdb
> Next trap will enter GDB remote protocol mode
> db> si step a single instruction to reenter ddb
> --
> after typing gdb command, it says: "The remote GDB backend could not
> be selected"
> that i am not sure what this indicates; looking at subr_kdb.c, wonder
> maybe kdb_dbbe_set is not set?  seems kdb_dbbe_set is not referenced
> anywhere, not sure how to get it right.
>
> thanks for shed some light ...
>
> On Mon, Oct 6, 2008 at 4:26 PM, Pietro Cerutti <gahr at freebsd.org> wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA512
>>
>> alan yang wrote:
>> | hi, there,
>> |
>> | wonder people can shed some lights on remote debugging.  i have
>> | freebsd7 configured with option DDB / KDB / GDB but after entering the
>> | db on the target system the command gdb gives "the remote GDB backend
>> | could not be selected".
>> |
>> | i browsed through the mailing list, and do find 1 similar post but
>> | without answer.
>> |
>> | thanks in advance & apology if i overlooked things ...
>>
>> I suggest the following tutorial:
>> http://www.lemis.com/grog/Papers/Debug-tutorial/tutorial.pdf
>>
>> Have fun :)
>>
>> |
>> | cheers,
>> | alan
>> | _______________________________________________
>> | freebsd-hackers at freebsd.org mailing list
>> | http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
>> | To unsubscribe, send any mail to "freebsd-hackers-unsubscribe at freebsd.org"
>>
>>
>> - --
>> Pietro Cerutti
>> gahr at FreeBSD.org
>>
>> PGP Public Key:
>> http://gahr.ch/pgp
>>
>> -----BEGIN PGP SIGNATURE-----
>> Version: GnuPG v2.0.9 (FreeBSD)
>>
>> iEYEAREKAAYFAkjqnpQACgkQwMJqmJVx945RSwCgoDb0JTr8LSFDB1vpAbGUjb76
>> ZH0An19HpFVJJTUB5/XnyZc0pIDzgxc3
>> =6Pdm
>> -----END PGP SIGNATURE-----
>>
>