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Date:      Mon, 30 Aug 1999 14:35:44 -0400 (EDT)
From:      Zhihui Zhang <zzhang@cs.binghamton.edu>
To:        freebsd-hackers@freebsd.org
Subject:   Help with remote debugging (gdb -k)
Message-ID:  <Pine.GSO.3.96.990830142223.10304D-100000@sol.cs.binghamton.edu>

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After reading the handbook and some postings in the mailing list archive. 
I still can not make remote debugging work.  I basically did the following
on FreeBSD-current 4.0 (A is debugging machine, B is the target): 

(1) Build a debug kernel (options DDB and BREAK_TO_DEBUGGER) on box A.
The sio flag I used is 0x90 (I also tried 0x80).  Ftp the file /kernel to
box B and renamed as /kernel.A

(2) Boot the kernel /kernel.A on box B with -d option:

>>FreeBSD/i386 boot
Default: 0:wd(0,a)/boot/loader
boot: /kernel.A -d
Debugger("Boot flags requested debugger")
Stopped at 0xc0252c27: movl $0, 0xc031ed98
db> gdb
Next trap will enter GDB remote protocol mode
db> s

(3) On machine A, go to the compile directory:

#gdb -g kernel.debug

(kgdb) target remote /dev/cuaa0

     Remote debugging using /dev/cuaa0
     Ignoring packet error, continuing...
     Ignoring packet error, continuing...
     Couldn't establish connection to remote target
     Malformed response to offset query, timeout

The serial cable is null-modem and has been tested with kermit. It is
connected to /dev/ttyd0 (com 1) of machine B and com 2 of machine A.

I did not do "strip -x" because I assume this is done by FreeBSD 4.0
automatically and the file debug.kernel is the one with symbols.

Any help is appreciated.

--------------------------------------------------
Zhihui Zhang.  Please visit http://www.freebsd.org
--------------------------------------------------




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