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Subject: Re: Kernel Debug Howto
From: Kristof Provost <kp@FreeBSD.org>
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Date: Sat, 25 Jul 2015 11:11:32 +0200
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To: HeTak <hetakcoder@gmail.com>
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> On 25 Jul 2015, at 10:54, HeTak <hetakcoder@gmail.com> wrote:
> I have recently started some developments on FreeBSD net section.
Great!

> But I am kinda new to this field. My base interest is to first =
understand the
> implementation structure via tracing the code and so.
>=20
> 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, =
=E2=80=A6

> 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=E2=80=99s style(9) for coding style.
I=E2=80=99d also recommend "The Design and Implementation of the FreeBSD =
Operating System=E2=80=9D
(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=E2=80=99re 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=E2=80=99s not so useful if you=E2=80=99re working on drivers, of =
course.

Regards,
Kristof=