From owner-freebsd-questions Fri Oct 18 17:47:29 2002 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 89D9A37B401 for ; Fri, 18 Oct 2002 17:47:27 -0700 (PDT) Received: from mail.dubium.com (h24-78-225-134.vn.shawcable.net [24.78.225.134]) by mx1.FreeBSD.org (Postfix) with ESMTP id 80A8C43E65 for ; Fri, 18 Oct 2002 17:47:25 -0700 (PDT) (envelope-from joe-dated-1035420567.6ba3af@dubium.com) Received: (qmail 68641 invoked from network); 19 Oct 2002 00:49:27 -0000 Received: from localhost (HELO fafner.dubium.com) ([127.0.0.1]) (envelope-sender ) by 0 (qmail-ldap-1.03) with SMTP for ; 19 Oct 2002 00:49:27 -0000 Content-Type: text/plain; charset="us-ascii" To: freebsd-questions@FreeBSD.ORG Subject: Trying to write a crash dump -> Trying to debug a kernel panic Date: Fri, 18 Oct 2002 17:48:04 -0700 X-Mailer: KMail [version 1.4] MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: <200210181748.04434.joe@dubium.com> From: Joe Sotham X-Delivery-Agent: TMDA/0.62 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG I am trying to debug a boot time kernel panic. This is completely new territory for me and I need some help. I'm taking this one step at a time, the first step is to get a crash dump. This is a repeateable panic which occurs when I boot from my windows partition to my FreeBSD partition. Once the panic occurs, booting again clears the problem. Following the documentation in -http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html has gotten me so far, but I am stuck. I can trap and get dumped into the debugger (I think it's the debugger, the prompt is "db>"). However I am trying to get a core dump written and that's where I am having no success. 1) I've added the kernel debugging options -- options DDB #Debug Support makeoptions DEBUG=-g options KTRACE ---------------- 2) made and installed the kernel, 3) added the following params to the rc.conf file -- dumpdir="/var/crash" dumpdev="/dev/ad0s2b" ------------- where dumpdev corresponds to the swap device the fstab entry corresponds below. ---- /dev/ad0s2b none swap sw 0 0 ------------ 4) executed the command "dumpon -v /dev/ad0s2b" 5) rebooted to wwindows 6) rebooted to freeBSD -> panic -> "db> prompt" 7) At this point I examined a few commands, (e.g. trace, show reg) and finished with the "panic" command which according to the documentation at http://www.freebsd.org/doc/en_US.ISO8859-1/ \ books/developers-handbook/x9854.html "This will cause your kernel to dump core and reboot, so you can later analyze the core on a higher level with gdb. " 8) At which the system rebooted and came up, but with no core file -------------------------------------------------------- Joe Sotham -------------------------------------------------------- Christianity got over the difficulty of furious opposites by keeping them both and keeping them furious. - G.K. Chesterton To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message