Remote kernel debugging question

[Benjamin Kaduk]

On Mon, 21 Jul 2014, Nidal Khalil wrote:

> 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. I appreciate the help.

I do not think I have actually used remote GDB kernel debugging on my own 
machines, but I wanted to make sure that you had seen the documentation 
for doing so, available at 
http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-online-gdb.html 
.  If it is incorrect, we should update it to be correct.

Thanks,

Ben Kaduk