From owner-freebsd-questions@FreeBSD.ORG Wed Apr 9 08:01:01 2003 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4099B37B401 for ; Wed, 9 Apr 2003 08:01:01 -0700 (PDT) Received: from smtp3.libero.it (smtp3.libero.it [193.70.192.127]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3E74343FA3 for ; Wed, 9 Apr 2003 08:01:00 -0700 (PDT) (envelope-from ml.ventu@flashnet.it) Received: from soth.ventu (151.42.126.110) by smtp3.libero.it (6.7.015) id 3E44E967016EF4D7 for freebsd-questions@FreeBSD.ORG; Wed, 9 Apr 2003 17:00:58 +0200 Received: from mailer (xanatar.ventu [10.1.2.6]) by soth.ventu (8.12.6p2/8.12.6) with SMTP id h39F4pOe003043 for ; Wed, 9 Apr 2003 17:04:51 +0200 (CEST) (envelope-from ml.ventu@flashnet.it) Message-Id: <200304091504.h39F4pOe003043@soth.ventu> To: freebsd-questions@FreeBSD.ORG Priority: Normal X-Mailer: Post Road Mailer for OS/2 (Green Edition Ver 3.0) Date: Wed, 9 Apr 2003 17:04:51 EST From: Andrea Venturoli Subject: Re: bpf -> kernel panic X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Andrea Venturoli List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Apr 2003 15:01:01 -0000 ** Reply to note from Giorgos Keramidas Tue, 18 Mar 2003 21:46:43 +0200 > > > Can you try building yourself a kernel with debugging information > > > and get a crash dump from the panic? > > > > I'll have a try. > > What should I do after I have a crash dump? > > Follow the instructions at > http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html > > Especially the first section: ``Debugging a Kernel Crash Dump with gdb''. Ok. It's been long time since this thread was put on hold... :) I've been able to build a debug kernel, install it, run it and happen to experience a crash in umount while shutting down to single user mode. Now I have this dump, I tried examining it, but I could not come to any useful conclusion. Before I produce a crash on purpose launching e.g. tcpdump, I'd like to understand the whole thing a little better, practising on this dump I have. (btw it's not the first time the machine dump on umount either). I'm a long time C/C++/Assembler programmer and I'm quite accustomed to basic gdb use, but of course that doesn't mean I'm able to understand at a glance code others have written, and I'm no FreeBSD kernel guru. So, I do I go about it? Is there anyone or any doc that can help me? Some sort of tutorial? Does anyone thinks he can get some useful information with a quick look at the whole stack backtrace? One things that puzzles me is that, in a few frames, the functions name is replaced with ???. If this is not the right place to ask, which is? Altough this is by no mean an urgent matter, I'd like to deal with it completely sooner or later bye & Thanks a lot av.