From owner-freebsd-current@FreeBSD.ORG Thu May 2 16:39:38 2013 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 9A93F13B; Thu, 2 May 2013 16:39:38 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) by mx1.freebsd.org (Postfix) with ESMTP id 754201813; Thu, 2 May 2013 16:39:38 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id C8DFFB993; Thu, 2 May 2013 12:39:37 -0400 (EDT) From: John Baldwin To: "Robert N. M. Watson" Subject: Re: panic: in_pcblookup_local (?) Date: Thu, 2 May 2013 12:08:39 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p25; KDE/4.5.5; amd64; ; ) References: <20130502005704.GB1623@glenbarber.us> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201305021208.39287.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Thu, 02 May 2013 12:39:37 -0400 (EDT) Cc: Ian FREISLICH , Glen Barber , freebsd-current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 May 2013 16:39:38 -0000 On Thursday, May 02, 2013 5:27:39 am Robert N. M. Watson wrote: > > On 2 May 2013, at 01:57, Glen Barber wrote: > > > So, I am admittedly not too familiar with DDB. In fact, I just now > > realize the kernel is built without DDB... > > DDB is a very powerful tool in that it's been custom-developed to help debug common kernel panics. It lacks some of the flexibility, and especially the data-type awareness of GDB, but GDB is a less well-suited tool when investigating common crash patterns. I'll usually start out debugging in DDB, and find that 90% of my in-development panics can be debugged with it, resorting to GDB for post-mortem analyses in production or particularly hard debugging cases (usually where DDB's pretty printers for data types fall short). I've wanted, for a long time, to teach DDB how to pretty-print arbitrary types using DTrace's CTF meta-data, which would address the most significant major case where I turn to GDB. Mind you, the limitations I see in GDB are made up for in most part by John's GDB scripts :-). Heh, I prefer DDB for active development as well, but after being forced to work in an environment where I had to largely do post-mortem analysis, I had to get a gdb environment that was close to as functional. Also, using kgdb on a live system to obtain info is less invasive than ddb (doesn't halt the system), and you can easily add new scripts to generate useful reports without having to recompile or reboot. -- John Baldwin