From owner-freebsd-current@FreeBSD.ORG Sun Jun 13 20:33:03 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DF3FA16A4CE for ; Sun, 13 Jun 2004 20:33:03 +0000 (GMT) Received: from mxfep02.bredband.com (mxfep02.bredband.com [195.54.107.73]) by mx1.FreeBSD.org (Postfix) with ESMTP id A2EBA43D41 for ; Sun, 13 Jun 2004 20:32:58 +0000 (GMT) (envelope-from peter.schuller@infidyne.com) Received: from scode.mine.nu ([83.226.138.12] [83.226.138.12]) by mxfep02.bredband.com with ESMTP id <20040613203200.IFZD1450.mxfep02.bredband.com@scode.mine.nu> for ; Sun, 13 Jun 2004 22:32:00 +0200 Received: from localhost (localhost [127.0.0.1]) by scode.mine.nu (Postfix) with ESMTP id 1C515F8F32 for ; Sun, 13 Jun 2004 22:37:09 +0200 (CEST) From: Peter Schuller To: current@freebsd.org Date: Sun, 13 Jun 2004 22:37:08 +0200 User-Agent: KMail/1.6 MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <200406132237.08445.peter.schuller@infidyne.com> Subject: Page fault in kernel mode; unable to dump core; reproducable X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 13 Jun 2004 20:33:04 -0000 Hello, i am experiencing a reproducable 'page fault while in kernel mode' with CURRENT (from a couple of weeks ago aswell as one cvsuped today). It happens extremely early during boot right after the root filesystem is mounted. This does not happen with 5.2.1-RELEASE. I have tried setting 'dumpdev' appropriately (/dev/ad0s2b in my case), but no crash dumps are written (not automatically, and not in response to the 'panic' command in the kernel debugger). What should I do in order to provide the necessary information about this bug? The bug *may* be triggered by the fact that the root filesystem has been mounted read-write since the last crash that originally marked the file system dirty. I do this sometimes to get around the fact that the startup sequence won't defer the root fs for bgfsck until it's been mounted rw at least once since being marked dirty. If I boot into single user mount it will survive mounting the root filesystem ro. It has also survived, at least once, remounting rw, but then crashed when I did a 'sync'. On another occasion, I let it boot to single user mode, mounting ro, after which it crashed when I did 'sysctl -a | grep dumpdev'. So. I have kept the filesystem dirty, interrupting the bg fsck_ufs when booting with 5.2.1 in order to maintain the state which triggers the bug. I had meant to post a full stack trace but since I am unable to obtain a dump, I will at least include what's on the screen even though it's probably useless: == Memory modified after free 0xc1c08600(508) val=1000100 @ 0xc1c08600 Fatal trap 12: page fault while in kernel mode fault virtual address = 0x1000120 fault code = supervisor read, page not present instruction pointer = 0x8 :0xc063d63e stack pointer = 0x10 :0xd5469984 frame pointer = 0x10 :0xd54699a0 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 = 64 (sh) kernel: type 12 trap, code=0 Stopped at mtrash_ctor+0x3a: movl 0x20(%eax),%eax -- / Peter Schuller, InfiDyne Technologies HB PGP userID: 0xE9758B7D or 'Peter Schuller ' Key retrieval: Send an E-Mail to getpgpkey@scode.org E-Mail: peter.schuller@infidyne.com Web: http://www.scode.org