Kernel Debug Howto

[HeTak]

On Sat, Jul 25, 2015 at 1:41 PM, Kristof Provost <kp at freebsd.org> wrote:

>
> > On 25 Jul 2015, at 10:54, HeTak <hetakcoder at gmail.com> wrote:
> > I have recently started some developments on FreeBSD net section.
> Great!
>
​Thank you Kristof, b
oth for your fast answering and your welcome.​ :)

>
> > But I am kinda new to this field. My base interest is to first
> understand the
> > implementation structure via tracing the code and so.
> >
> > I have three major questions:
> > 1-  how to debug changes made to FreeBSD kernel?
> > (You know, till some levels, I can even use uprintf or so, but, for
> example
> > inside radix.c (where I wanna understand how a route is checked to be
> > unique and then inserted to the tree) I can't do such checks..)
> dtrace can be quite useful to understand flows. You can grab stack traces
> (i.e. figure out where things are called from), get function arguments, …


> > 2- are there standards there for freebsd kernel developments of which I
> can
> > follow so my job gets a bit simplified?
> > (Any development guides or so?I prospect it to be some differences
> between
> > system developments and normal coding, but I don't have an idea on how to
> > get that).
> There’s style(9) for coding style.
> I’d also recommend "The Design and Implementation of the FreeBSD Operating
> System”
> (the second edition).
>
> > 3- what is the fastest way to apply changes to FreeBSD kernel?
> > (For now, I just follow the normal build & install kernel & reboot.)
> I pretty much do that. Depending on what you’re working on it might be
> easier to run it in a VM.
> My work lately has been on the network code, so a VM is very convenient.
> It’s not so useful if you’re working on drivers, of course.
>
​
​Great to hear of such a tool as Dtrace and also the book. and actually I'm
using a VM as well. ​

​I'll check these and hope to be successful through my way.

>
> Regards,
> Kristof


​Cheerio,
HeTak​