From owner-freebsd-bugs@FreeBSD.ORG Sun Jan 9 02:10:05 2011 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 431541065679 for ; Sun, 9 Jan 2011 02:10:05 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 03D448FC1A for ; Sun, 9 Jan 2011 02:10:05 +0000 (UTC) Received: from freefall.freebsd.org (localhost [127.0.0.1]) by freefall.freebsd.org (8.14.4/8.14.4) with ESMTP id p092A4I6008048 for ; Sun, 9 Jan 2011 02:10:04 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.4/8.14.4/Submit) id p092A4Sh008047; Sun, 9 Jan 2011 02:10:04 GMT (envelope-from gnats) Resent-Date: Sun, 9 Jan 2011 02:10:04 GMT Resent-Message-Id: <201101090210.p092A4Sh008047@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Nick Sayer Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1BF2A1065696 for ; Sun, 9 Jan 2011 02:09:32 +0000 (UTC) (envelope-from nsayer@quack.kfu.com) Received: from quack.kfu.com (kfu-1-pt.tunnel.tserv4.nyc4.ipv6.he.net [IPv6:2001:470:1f06:e09::2]) by mx1.freebsd.org (Postfix) with ESMTP id 9E1E88FC1B for ; Sun, 9 Jan 2011 02:09:31 +0000 (UTC) Received: from quack.kfu.com (localhost [127.0.0.1]) by quack.kfu.com (8.14.4/8.14.4) with ESMTP id p0929SYt003110 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 8 Jan 2011 18:09:30 -0800 (PST) (envelope-from nsayer@quack.kfu.com) Received: (from nsayer@localhost) by quack.kfu.com (8.14.4/8.14.4/Submit) id p0929Ref003109; Sat, 8 Jan 2011 18:09:27 -0800 (PST) (envelope-from nsayer) Message-Id: <201101090209.p0929Ref003109@quack.kfu.com> Date: Sat, 8 Jan 2011 18:09:27 -0800 (PST) From: Nick Sayer To: FreeBSD-gnats-submit@FreeBSD.org X-Send-Pr-Version: 3.113 Cc: Subject: kern/153804: boot from zfs kernel.old recovery undocumented/impossible X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Nick Sayer List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 09 Jan 2011 02:10:05 -0000 >Number: 153804 >Category: kern >Synopsis: boot from zfs kernel.old recovery undocumented/impossible >Confidential: no >Severity: critical >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: doc-bug >Submitter-Id: current-users >Arrival-Date: Sun Jan 09 02:10:04 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Nick Sayer >Release: FreeBSD 8.2-RC1 amd64 >Organization: Just me >Environment: System: FreeBSD quack.kfu.com 8.2-RC1 FreeBSD 8.2-RC1 #5: Sat Jan 8 16:14:48 PST 2011 root@quack.kfu.com:/usr/obj/usr/src/sys/QUACK amd64 Disk configured for gptzfsboot, root on ZFS >Description: After creating an unbootable kernel, the steps necessary to boot kernel.old are unclear. The problem is that under normal circumstances, /boot/zfs/zpool.cache is loaded in some magic way - this is evidenced by breaking into the loader (by pressing "6") and doing an lsmod. If you attempt to unload, then manually load kernel and zfs.ko, the zpool.cache file is not loaded. Attempting to load zpool.cache with the load command fails, and there is no alternative command to do so. Attempting to boot the kernel without the zpool.cache loaded results in an irrecoverable failure to mount root. >How-To-Repeat: Set up a zfsroot system. boot. hit '6' at the loader menu, then "unload", "load kernel" and "load zfs.ko", then "boot". >Fix: Either loading zfs.ko needs to perform whatever magic is necessary to fetch zpool.cache, or a command needs to be added (like load_geli) to fetch the zpool cache. >Release-Note: >Audit-Trail: >Unformatted: