From owner-freebsd-hackers@FreeBSD.ORG Thu May 20 06:00:07 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5742B16A4CE for ; Thu, 20 May 2004 06:00:07 -0700 (PDT) Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1360E43D3F for ; Thu, 20 May 2004 06:00:07 -0700 (PDT) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.12.10/8.12.10) with ESMTP id i4KD04qM018895 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 20 May 2004 09:00:04 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.12.9p2/8.12.9/Submit) id i4KCxwtM028135; Thu, 20 May 2004 08:59:58 -0400 (EDT) (envelope-from gallatin) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16556.43982.226708.375607@grasshopper.cs.duke.edu> Date: Thu, 20 May 2004 08:59:58 -0400 (EDT) To: Nick Strebkov In-Reply-To: <20040519133442.GA90053@nord.interexc.com> References: <20040519133442.GA90053@nord.interexc.com> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid cc: hackers@freebsd.org Subject: Re: obtaining a kernel crash dump X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 May 2004 13:00:07 -0000 Nick Strebkov writes: > May 19 16:17:00 devel /kernel: > May 19 16:17:00 devel /kernel: syncing disks... 60 3 2 > > [dd boot kernel messages] Try disabling sync-on-panic. It almost always causes problems for me when trying to get dumps. % cat /etc/sysctl.conf kern.sync_on_panic=0 If you are running a newer version of FreeBSD with the DDB_TRACE options, you want to enable DDB and DDB_TRACE. This will get you a stack trace on console, which is a heck of a lot better than nothing if your crashdumps don't work. options DDB #Enable the kernel debugger options DDB_TRACE Sometimes I have problems getting a dump on 5.x if I've dropped into ddb, so I use the following to prevent the system from dropping to a DDB prompt at panic: options DDB_UNATTENDED Drew