Date: Tue, 7 Oct 2008 10:53:22 -0700 From: "alan yang" <alancyang@gmail.com> To: freebsd-questions@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: kgdb debugging Message-ID: <290865fd0810071053k6da13d96j391ade1a30599fa1@mail.gmail.com> In-Reply-To: <290865fd0810061712sfdf5a0p4d3954773ee27a3d@mail.gmail.com> References: <290865fd0810061544ubbe92fdsf75501bb729da3f0@mail.gmail.com> <48EA9E95.80105@FreeBSD.org> <290865fd0810061712sfdf5a0p4d3954773ee27a3d@mail.gmail.com>
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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@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@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@freebsd.org mailing list >> | http://lists.freebsd.org/mailman/listinfo/freebsd-hackers >> | To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >> >> >> - -- >> Pietro Cerutti >> gahr@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----- >> >
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