From owner-freebsd-current@FreeBSD.ORG  Tue Jan 20 19:02:47 2015
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id E86127AA;
 Tue, 20 Jan 2015 19:02:47 +0000 (UTC)
Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1])
 (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id C2B54BCF;
 Tue, 20 Jan 2015 19:02:47 +0000 (UTC)
Received: from jhbbsd.localnet (unknown [209.249.190.124])
 by bigwig.baldwin.cx (Postfix) with ESMTPSA id AF7A3B9A5;
 Tue, 20 Jan 2015 14:02:46 -0500 (EST)
From: John Baldwin <jhb@freebsd.org>
To: freebsd-current@freebsd.org
Subject: Re: [PATCH] nmbclusters should be always positive
Date: Tue, 20 Jan 2015 11:19:23 -0500
User-Agent: KMail/1.13.5 (FreeBSD/8.4-CBSD-20140415; KDE/4.5.5; amd64; ; )
References: <CACYV=-HiK_DHTaZzjs2G9+chwYYyX=LnkztF7UKNAUY0RpTGZQ@mail.gmail.com>
In-Reply-To: <CACYV=-HiK_DHTaZzjs2G9+chwYYyX=LnkztF7UKNAUY0RpTGZQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-Id: <201501201119.23123.jhb@freebsd.org>
X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7
 (bigwig.baldwin.cx); Tue, 20 Jan 2015 14:02:46 -0500 (EST)
Cc: Davide Italiano <davide@freebsd.org>
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
 <freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-current>, 
 <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current/>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
 <mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 20 Jan 2015 19:02:48 -0000

On Monday, January 19, 2015 6:12:25 pm Davide Italiano wrote:
> Currently, the following is allowed in FreeBSD:
> 
> root@rabbit1:/home/davide/udp-clt # sysctl kern.ipc.nmbclusters=2147483647
> kern.ipc.nmbclusters: 2036598 -> -2147483648
> 
> The following is an attempt of fixing.
> I also think nmbcluster should actually be u_int and not it, but this
> is a discussion for another day, maybe.
> 
> diff --git a/sys/kern/kern_mbuf.c b/sys/kern/kern_mbuf.c
> index 7ab6509..15b38a9 100644
> --- a/sys/kern/kern_mbuf.c
> +++ b/sys/kern/kern_mbuf.c
> @@ -162,7 +162,7 @@ sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
>         newnmbclusters = nmbclusters;
>         error = sysctl_handle_int(oidp, &newnmbclusters, 0, req);
>         if (error == 0 && req->newptr && newnmbclusters != nmbclusters) {
> -               if (newnmbclusters > nmbclusters &&
> +               if (newnmbclusters > 0 && newnmbclusters > nmbclusters &&
>                     nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 +
> nmbjumbo16) {
>                         nmbclusters = newnmbclusters;
>                         nmbclusters = uma_zone_set_max(zone_clust, 
nmbclusters);

1) If you fix this one you need to fix the other handlers in this file (all 
the jumbo ones, etc.)

2) Shouldn't the 'newnmbclusters > nmbclusters' check catch this already?  
That should fail right?  Might be worth figuring out why it isn't.

-- 
John Baldwin