From owner-freebsd-arch@FreeBSD.ORG  Sat Feb  9 08:51:51 2013
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: freebsd-arch@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id B015DA74
 for <freebsd-arch@freebsd.org>; Sat,  9 Feb 2013 08:51:51 +0000 (UTC)
 (envelope-from christoph.mallon@gmx.de)
Received: from mout.gmx.net (mout.gmx.net [212.227.15.18])
 by mx1.freebsd.org (Postfix) with ESMTP id 37A83EB8
 for <freebsd-arch@freebsd.org>; Sat,  9 Feb 2013 08:51:50 +0000 (UTC)
Received: from mailout-de.gmx.net ([10.1.76.35]) by mrigmx.server.lan
 (mrigmx001) with ESMTP (Nemesis) id 0M38or-1UtioD0o47-00srxa for
 <freebsd-arch@FreeBSD.org>; Sat, 09 Feb 2013 09:51:50 +0100
Received: (qmail invoked by alias); 09 Feb 2013 08:51:46 -0000
Received: from p5B132F8B.dip.t-dialin.net (EHLO rotluchs.lokal) [91.19.47.139]
 by mail.gmx.net (mp035) with SMTP; 09 Feb 2013 09:51:46 +0100
X-Authenticated: #1673122
X-Provags-ID: V01U2FsdGVkX1+XsO9v6R2XFN3z8J8TXtMYdJ94IeLHfxJ9EX48/d
 Z1zxNQSI/LH3N+
Message-ID: <51160E06.1070404@gmx.de>
Date: Sat, 09 Feb 2013 09:51:18 +0100
From: Christoph Mallon <christoph.mallon@gmx.de>
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64;
 rv:17.0) Gecko/20130129 Thunderbird/17.0.2
MIME-Version: 1.0
To: Andriy Gapon <avg@FreeBSD.org>
Subject: Re: Proposal: Unify printing the function name in panic messages()
References: <51141E33.4080103@gmx.de> <511426B8.2070800@FreeBSD.org>
In-Reply-To: <511426B8.2070800@FreeBSD.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
X-Y-GMX-Trusted: 0
Cc: Kirk McKusick <mckusick@mckusick.com>, freebsd-arch@FreeBSD.org
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-arch>,
 <mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
 <mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 09 Feb 2013 08:51:51 -0000

On 07.02.2013 23:12, Andriy Gapon wrote:
> on 07/02/2013 23:35 Christoph Mallon said the following:
>> panic("just a message");
> 
> This seems perfect.
> Panic without at least a stack trace or preferably a crash dump is practically
> useless in most cases.  A stack trace already has all the function names.
> So a function name in a message seems to be redundant.

This is nice in theory, but infeasible in practice.
More than half of the panic() calls include the correct function name in a way or another.
I estimate, that another quarter show a wrong name.
It is hard to get this number mechanically, because, well, the names are wrong.
So most calls include the name (or try to).
Having no function name is a minority.
I plan to correct and unify this hotchpotch.
Also, if stack traces are disabled, you at least can reliably determine, where the panic came from.
Finally, you can turn the names on and off with one central switch.

	Christoph