From owner-svn-src-head@freebsd.org  Thu Jan 25 00:16:32 2018
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 80935ECEBC5;
 Thu, 25 Jan 2018 00:16:32 +0000 (UTC)
 (envelope-from srs0=ghjn=eu=freebsd.org=kp@codepro.be)
Received: from venus.codepro.be (venus.codepro.be [IPv6:2a01:4f8:162:1127::2])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256
 bits))
 (Client CN "*.codepro.be", Issuer "Gandi Standard SSL CA 2" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id 1F52D7F269;
 Thu, 25 Jan 2018 00:16:31 +0000 (UTC)
 (envelope-from srs0=ghjn=eu=freebsd.org=kp@codepro.be)
Received: from [192.168.228.1] (unknown [138.44.250.147])
 (Authenticated sender: kp)
 by venus.codepro.be (Postfix) with ESMTPSA id 24399BC69;
 Thu, 25 Jan 2018 01:16:27 +0100 (CET)
From: "Kristof Provost" <kp@FreeBSD.org>
To: "Gleb Smirnoff" <glebius@FreeBSD.org>
Cc: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: Re: svn commit: r328313 - head/sys/netpfil/pf
Date: Thu, 25 Jan 2018 11:16:23 +1100
X-Mailer: MailMate (2.0BETAr6103)
Message-ID: <F461DD1E-DBA0-4E5B-8725-FE1ED775F9AB@FreeBSD.org>
In-Reply-To: <20180125001310.GJ8113@FreeBSD.org>
References: <201801240429.w0O4THIl059440@repo.freebsd.org>
 <20180125001310.GJ8113@FreeBSD.org>
MIME-Version: 1.0
Content-Type: text/plain; format=flowed; markup=markdown
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.25
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 25 Jan 2018 00:16:32 -0000

On 25 Jan 2018, at 11:13, Gleb Smirnoff wrote:
> On Wed, Jan 24, 2018 at 04:29:17AM +0000, Kristof Provost wrote:
> K> Author: kp
> K> Date: Wed Jan 24 04:29:16 2018
> K> New Revision: 328313
> K> URL: https://svnweb.freebsd.org/changeset/base/328313
> K>
> K> Log:
> K>   pf: States have at least two references
> K>
> K>   pf_unlink_state() releases a reference to the state without 
> checking if
> K>   this is the last reference. It can't be, because 
> pf_state_insert()
> K>   initialises it to two. KASSERT() that this is always the case.
> K>
> K>   CID:	1347140
> K>

> K> +	last = refcount_release(&s->refs);
> K> +	KASSERT(last == 0, ("Incorrect state reference count"));
> K>
> K>  	return (pf_release_state(s));
> K>  }
>
> IMHO, we shouldn't emit extra code to please Coverity. We can mark it
> as a false positive in the interface. It may make sense to add a 
> comment
> for a human to explain why return isn't checked here.
>
I find the KASSERT() to be a good way of verifying that this assumption 
is in fact correct.
You do have a good point about the comment.

Regards,
Kristof