Date: Fri, 18 Oct 2002 17:48:04 -0700 From: Joe Sotham <joe-dated-1035420567.6ba3af@dubium.com> To: freebsd-questions@FreeBSD.ORG Subject: Trying to write a crash dump -> Trying to debug a kernel panic Message-ID: <200210181748.04434.joe@dubium.com>
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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
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