From owner-freebsd-hackers@FreeBSD.ORG  Tue Mar 23 11:22:49 2010
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 4D9D11065672
	for <freebsd-hackers@freebsd.org>; Tue, 23 Mar 2010 11:22:49 +0000 (UTC)
	(envelope-from des@des.no)
Received: from smtp.des.no (smtp.des.no [194.63.250.102])
	by mx1.freebsd.org (Postfix) with ESMTP id 12F408FC20
	for <freebsd-hackers@freebsd.org>; Tue, 23 Mar 2010 11:22:48 +0000 (UTC)
Received: from ds4.des.no (des.no [84.49.246.2])
	by smtp.des.no (Postfix) with ESMTP id C73EF1FFC51;
	Tue, 23 Mar 2010 11:22:47 +0000 (UTC)
Received: by ds4.des.no (Postfix, from userid 1001)
	id A6F57844DA; Tue, 23 Mar 2010 12:22:47 +0100 (CET)
From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Dmitry Krivenok <krivenok.dmitry@gmail.com>
References: <da48cf211003230218n56794f0bs27eef860efc0da3e@mail.gmail.com>
Date: Tue, 23 Mar 2010 12:22:47 +0100
In-Reply-To: <da48cf211003230218n56794f0bs27eef860efc0da3e@mail.gmail.com>
	(Dmitry Krivenok's message of "Tue, 23 Mar 2010 12:18:24 +0300")
Message-ID: <86ocifcmew.fsf@ds4.des.no>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.95 (berkeley-unix)
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Cc: freebsd-hackers@freebsd.org
Subject: Re: Strange behavior of kernel module (output terminated)
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 23 Mar 2010 11:22:49 -0000

Dmitry Krivenok <krivenok.dmitry@gmail.com> writes:
> /* The function called at load/unload. */
> static int event_handler(struct module *module, int event, void *arg)
> {
>   int e =3D 0; /* Error, 0 for normal return status */
>   switch (event)
>     {
>       case MOD_LOAD:
>         uprintf("Hello FreeBSD kernel!\n");

I'm not sure it's such a good idea to use uprintf() here.  The event
handler can be called in non-process context.

>         int i =3D 0;
>         for(i =3D 0; i < 1000; i++)
>           {
>             uprintf("%3d ", i);
>             if(! (i % 10) ) uprintf("\n");
>           }

(i % 10) is not a predicate.  The test should be if (i % 10 =3D=3D 0).

If you want to work on FreeBSD, I recommend you get used to the
FreeBSD coding style; see 'man 9 style'.

> As you can see the loop was terminated after i=3D=3D466.  I tried to
> load/unload the module many times but the last printed number was
> always 466.

You filled up a buffer somewhere...

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no