Date: Tue, 7 Oct 2008 11:12:06 -0700 From: "Navdeep Parhar" <nparhar@gmail.com> To: "alan yang" <alancyang@gmail.com> Cc: freebsd-hackers@freebsd.org, freebsd-questions@freebsd.org Subject: Re: kgdb debugging Message-ID: <d04e16b70810071112k76a61de2nf8f3feb59c5ab69c@mail.gmail.com> In-Reply-To: <290865fd0810071053k6da13d96j391ade1a30599fa1@mail.gmail.com> References: <290865fd0810061544ubbe92fdsf75501bb729da3f0@mail.gmail.com> <48EA9E95.80105@FreeBSD.org> <290865fd0810061712sfdf5a0p4d3954773ee27a3d@mail.gmail.com> <290865fd0810071053k6da13d96j391ade1a30599fa1@mail.gmail.com>
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On Tue, Oct 7, 2008 at 10:53 AM, alan yang <alancyang@gmail.com> wrote: > Could people shed some light how to get remote debugging going, must > be something that i overlooked, really appreciate. > Do you have the right flags for sio or uart in /boot/device.hints? I have this (for a recent HEAD):: hint.uart.0.flags="0x90" You are probably using sio as it is a FreeBSD7 system. From the man page of sio (the part that talks about flags):: ... 0x00080 use this port for remote kernel debugging ... Make sure you have this bit set. Regards, Navdeep > 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----- >>> >> > _______________________________________________ > 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" >
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