Remote kernel debugging question

Nidal Khalil nedmath at
Mon Jul 21 06:24:48 UTC 2014

Hello All,
I am somewhat new to BSD kernel but I am trying to debug a kernel module
using remote debugging.
I am using 9.2 RELEASE.
I setup and compiled the kernel with the following:

makeoptions DEBUG=-g
options          KDB
options          KDB_TRACE
options          DDB_CTF
options          DDB
options          GDB
options          ALT_BREAK_TO_DEBUGGER

I setup the uart for serial1 flags to 0x90 and I can read and write to the
serial from either machine
Both machines have the same kernel booted.
I can enter ddb but I can not launch gdb
The remote GDB backend could not be selected.
sysctl -a | grep debug.kdb

debug.kdb.available: ddb
Is that correct or it should be:
debug.kdb.available: ddb gdb

How do I enable gdb backend. Thanks


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