How to debug Fiasco Kernel

Marcus Hähnel mhaehnel at
Thu Sep 18 10:49:36 CEST 2014

Hi Cem,

On 2014-09-18 10:00, cem akpolat wrote:
> Dear all,
> I was searching how to debug the fiasco kernel through JDB. The
> following link gives a good approach how to it through minicom.
> [1]
> However, even if I see the messages on the screen, is it possible to
> interact with JDB without having an exception? I looked at also the
> "Fiasco Kernel Debugger Manual", however, I couldn't figure out how to
> exactly interact with JDB. Until now I could only interact with JDB in
> case of any exception occurrence. 

you can interact with the debugger either by pressing ESC at any time 
(requiring fiasco to be started with the -serial_esc option!).
If you want to invoke the debugger at any point in your code you can 
also use the


function. It is defined in l4/sys/kdebug.h. Just include this header 
and put enter_kdebug in your code when you wish to go into the debugger.

- Marcus

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