From owner-freebsd-stable@FreeBSD.ORG Fri Jun 23 15:29:37 2006 Return-Path: X-Original-To: stable@freebsd.org Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 309C616A47C for ; Fri, 23 Jun 2006 15:29:37 +0000 (UTC) (envelope-from gavin.atkinson@ury.york.ac.uk) Received: from mail-gw4.york.ac.uk (mail-gw4.york.ac.uk [144.32.128.249]) by mx1.FreeBSD.org (Postfix) with ESMTP id CA71343D77 for ; Fri, 23 Jun 2006 15:29:27 +0000 (GMT) (envelope-from gavin.atkinson@ury.york.ac.uk) Received: from buffy.york.ac.uk (buffy-128.york.ac.uk [144.32.128.160]) by mail-gw4.york.ac.uk (8.13.6/8.13.6) with ESMTP id k5NFT0E6014228; Fri, 23 Jun 2006 16:29:00 +0100 (BST) Received: from buffy.york.ac.uk (localhost [127.0.0.1]) by buffy.york.ac.uk (8.13.6/8.13.6) with ESMTP id k5NFSoiq070765; Fri, 23 Jun 2006 16:28:55 +0100 (BST) (envelope-from gavin.atkinson@ury.york.ac.uk) Received: (from ga9@localhost) by buffy.york.ac.uk (8.13.6/8.13.6/Submit) id k5NFSoke070764; Fri, 23 Jun 2006 16:28:50 +0100 (BST) (envelope-from gavin.atkinson@ury.york.ac.uk) X-Authentication-Warning: buffy.york.ac.uk: ga9 set sender to gavin.atkinson@ury.york.ac.uk using -f From: Gavin Atkinson To: David Wolfskill In-Reply-To: <20060615232240.GX32476@bunrab.catwhisker.org> References: <20060615232240.GX32476@bunrab.catwhisker.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Fri, 23 Jun 2006 16:28:49 +0100 Message-Id: <1151076529.62769.17.camel@buffy.york.ac.uk> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 FreeBSD GNOME Team Port X-York-MailScanner: Found to be clean X-York-MailScanner-From: gavin.atkinson@ury.york.ac.uk Cc: stable@freebsd.org Subject: Re: Help? 6.1-S: Fatal trap 12: page fault while in kernel mode X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Jun 2006 15:29:37 -0000 On Thu, 2006-06-15 at 16:22 -0700, David Wolfskill wrote: > I had one of these a couple of weeks ago or so; I had been distracted by > some more urgent matters that came up (the panic was on a machine under > test; the more urgent matters were little things like needing to deploy > a handful of resolvers on our network because existing ones were running > on systems that had provided evidence of being prone to imminent > failure). > > Anyway: I updated the 2 boxen under test to 6.1-STABLE as of this > morning, and finally(!) had a chance to re-try the failing operation. > > It went "kaboom!" again. :-{ (Well, there's something to be said for > consistency. :-}) > > It seems to run OK (albeit slowly) for a couple of minutes; then the > serial console reports: > > Fatal trap 12: page fault while in kernel mode > cpuid = 0; apic id = 06 > fault virtual address = 0x0 > fault code = supervisor read, page not present > instruction pointer = 0x20:0x0 > stack pointer = 0x28:0xf09b3b98 > frame pointer = 0x28:0xf09b3bcc > code segment = base 0x0, limit 0xfffff, type 0x1b > = DPL 0, pres 1, def32 1, gran 1 > processor eflags = interrupt enabled, resume, IOPL = 0 > current process = 23782 (ecelerity) > [thread pid 23782 tid 100120 ] > Stopped at 0: *** error reading from address 0 *** > db> trace > Tracing pid 23782 tid 100120 td 0xcc445180 > db> OK, seeing as nobody has offered any advice, I'll have a go. Have you got a debug kernel? If so, get a kernel dump. Load it into kgdb. Chances are "bt" won't work as the instruction pointer is zero, so instead you need to display the stack directly: (kgdb) x/80xw 0xf09b3b98 Look for any addresses in the 0xc0xxxxxx range - these will probably be pointers to kernel functions. Drop out of kgdb, and try to find out which functions these belong to: addr2line 0xc0639bd6 -e kernel.debug /usr/src/sys/kern/tty.c:1653 You can build up a backtrace and knowledge of atguments given to functions this way. Gavin