Here is script of my session between -----:
-----
Script started on Mon Nov 28 17:59:06 2005
bash-2.05b$ gdb netbsd.gdb
GNU gdb 5.3nb1
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain 
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "mipsel--netbsd"...
(gdb) target kcore /tmp/netbsd.3.core
Undefined target command: "kcore /tmp/netbsd.3.core".  Try "help target".
(gdb) help target
Connect to a target machine or process.
The first argument is the type or protocol of the target machine.
Remaining arguments are interpreted by the target protocol.  For more
information on the arguments for a particular protocol, type
`help target ' followed by the protocol name.

List of target subcommands:

target async -- Use a remote computer via a serial line
target child -- Unix child process (started by the "run" command)
target cisco -- Use a remote machine via TCP
target core -- Use a core file as a target
target exec -- Use an executable file as a target
target extended-async -- Use a remote computer via a serial line
target extended-remote -- Use a remote computer via a serial line
target remote -- Use a remote computer via a serial line

Type "help target" followed by target subcommand name for full 
documentation.
Command name abbreviations are allowed if unambiguous.
(gdb) target core /tmp/netbsd.3.core
"/tmp/netbsd.3.core" is not a core dump: File format not recognized
(gdb) quit
-----

I am running the following kernel:

NetBSD restorecd.homeunix.org 2.1_STABLE NetBSD 2.1_STABLE (SERVER) #0: 
Mon Nov 28 04:37:42 UTC 2005 
xxx@restorecd.homeunix.org:/home/xxx/build/2-1/src/sys/arch/cobalt/compile/SERVER 
cobalt

I built it last night using config file that I created earlier. And I do 
have netbsd.gdb around. Can I use that to boot my qube?

It is a cobalt port that I am running. Here is file on my gdb:
/usr/bin/gdb: ELF 32-bit LSB MIPS-I executable, MIPS, version 1 (SYSV), 
for NetBSD 2.1, dynamically linked (uses shared libs), not stripped

So it is from the correct version of netbsd. Somehow kcore target is 
missing from that version. I wonder how other people debug mips kernel?

Regards,
Alex



Hubert Feyrer wrote:
> On Sun, 27 Nov 2005, Alex Pelts wrote:
> 
>> FAQ states that I need to do "target kcore" command in the gdb but gdb 
>> does not have a kcore target and "target core" complains about the 
>> file format.
> 
> 
> What version of NetBSD, and what error do you get?
> For me this works fine on 2.1/i386 (actually, I don't know from what OS 
> version the crashdumps are, might be old):
> 
>     noon# cd /var/crash/
>     noon# ls
>     bounds              netbsd.0            netbsd.1.core.gz    
> netbsd.3.core.gz
>     minfree             netbsd.0.core       netbsd.2.core.gz
> ===>    noon# gdb netbsd.0
>     GNU gdb 5.3nb1
>     Copyright 2002 Free Software Foundation, Inc.
>     GDB is free software, covered by the GNU General Public License, and 
> you are
>     welcome to change it and/or distribute copies of it under certain 
> conditions.
>     Type "show copying" to see the conditions.
>     There is absolutely no warranty for GDB.  Type "show warranty" for 
> details.
>     This GDB was configured as "i386--netbsdelf"...(no debugging symbols 
> found)...
> ===>    (gdb) target kcore netbsd.0.core
>     #0  0x07ee0000 in ?? ()
> ===>    (gdb) bt
>     #0  0x07ee0000 in ?? ()
>     #1  0xc02f9133 in cpu_reboot ()
>     #2  0xc0241278 in db_sync_cmd ()
>     ...
> 
>> I compiled somewhat reduced kernel but why should it crash during ftp 
>> transfer?
> 
> 
> No idea - I guess there's a panic message that tells you.
> Or what do you mean by "crash"? Normal ftpd.core?
> 
> 
>  - Hubert
> 
> 
>