From owner-cvs-all@FreeBSD.ORG Tue Jan 20 20:08:51 2004 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4E3FA16A4CE; Tue, 20 Jan 2004 20:08:51 -0800 (PST) Received: from harmony.village.org (rover.bsdimp.com [204.144.255.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id A521A43D2F; Tue, 20 Jan 2004 20:08:47 -0800 (PST) (envelope-from imp@bsdimp.com) Received: from localhost (warner@rover2.village.org [10.0.0.1]) by harmony.village.org (8.12.10/8.12.9) with ESMTP id i0L48iET087194; Tue, 20 Jan 2004 21:08:44 -0700 (MST) (envelope-from imp@bsdimp.com) Date: Tue, 20 Jan 2004 21:08:41 -0700 (MST) Message-Id: <20040120.210841.22504092.imp@bsdimp.com> To: rwatson@FreeBSD.org From: "M. Warner Losh" In-Reply-To: References: <200401210307.i0L37s7E060437@gw.catspoiler.org> X-Mailer: Mew version 3.3 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: wpaul@FreeBSD.org cc: src-committers@FreeBSD.org cc: phk@FreeBSD.org cc: bde@zeta.org.au cc: cvs-src@FreeBSD.org cc: truckman@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/alpha/alpha support.s src/sys/i386/i386 swtch.s src/sys/kern kern_shutdown.c src/sys/sys systm.h X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Jan 2004 04:08:51 -0000 In message: Robert Watson writes: : : On Tue, 20 Jan 2004, Don Lewis wrote: : : > It would be extremely helpful to preserve the panic message and : > (optionally) the backtrace across the reboot. Crash dumps may not : > always be possible for any number of reasons (swap smaller than RAM, : > /var/crash too small or overflowing with previous crash dumps, crash : > dump takes too long ...). This is especially true in cases where the : > machine crashes and reboots unattended. : : Actually, I was having a very similar conversation with Bill Paul this : afternoon. We were discussing dropping a copy of the kernel message : buffer onto the header of swap space on panic, if possible, and then : dropping them in /var/log/crash.log for management by newsyslog. Then the : natural response to "My machine spontaneously reboots" becomes "Look for : something recent in /var/log/crash.log", as opposed to "You'll need to : enable crash dumps, set up a serial console", etc. It's also something we : could turn on by default, as opposed to crash dumps, which would otherwise : consume of alot of disk space. I assume you are talking about reading them out of swap space on boot so you'd see something like the following in your logs: foo: first reboot after kernel panic Right? Then the message would be zeroed out, so you don't get it on a normal reboot, right? Warner