From owner-freebsd-questions@freebsd.org Fri Nov 11 08:18:41 2016 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DB3A6C3BACE for ; Fri, 11 Nov 2016 08:18:41 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from mx01.qsc.de (mx01.qsc.de [213.148.129.14]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A514A1E01 for ; Fri, 11 Nov 2016 08:18:41 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from r56.edvax.de (port-92-195-250-109.dynamic.qsc.de [92.195.250.109]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx01.qsc.de (Postfix) with ESMTPS id E9E803CEAA; Fri, 11 Nov 2016 09:18:38 +0100 (CET) Received: from r56.edvax.de (localhost [127.0.0.1]) by r56.edvax.de (8.14.5/8.14.5) with SMTP id uAB8IcZp003261; Fri, 11 Nov 2016 09:18:38 +0100 (CET) (envelope-from freebsd@edvax.de) Date: Fri, 11 Nov 2016 09:18:38 +0100 From: Polytropon To: Mick mtn Cc: freebsd-questions@freebsd.org Subject: Re: Access to shell during or after kernel panic? Message-Id: <20161111091838.69e2ae06.freebsd@edvax.de> In-Reply-To: References: Reply-To: Polytropon Organization: EDVAX X-Mailer: Sylpheed 3.1.1 (GTK+ 2.24.5; i386-portbld-freebsd8.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Nov 2016 08:18:42 -0000 On Fri, 11 Nov 2016 00:18:39 -0700, Mick mtn wrote: > FreeBSD 11R on macbook pro. > does not see dvd, yet the system was installed via > FreeBSD-11.0-RELEASE-amd64-dvd1.iso > ---------------------------------------------------------------- > partial panic printout: > module visa failed to register: 17 > kbd0 at kbdmux0 > Panic Module_register_init > CPUID=0 > ... > ... > ... > #1 0 . . . kdb backtrace at 0x67 > #2 ... vpanic at 0x182 > #3 panic at 0x43 > #4 module_register_init at 0x11c > #5 mi_startup at 0x118 > #6 btext at 0x2c > > uptime 1s > ----------------------------------------------------------------- > I can see the files in the rescue directory, but can not move to that > directory or issue commands like rescue/vi -v boot/loader.conf After a kernel panic, you usually cannot access the shell anymore, not locally, not remotely. But you can press Ctrl+Alt+Esc to enter the kernel debugger (which probably won't be much help at this point). > ANY HINTS on possible keyboard combinations to force boot from dvd? > Holding "C" on boot is not getting the result i expected. Is pressing C at boot a Mac-specific action? When you can access the FreeBSD loader prompt, entering the command "boot -C" will usually try to boot from optical media. This is the same prompt where you can unload unwanted kernel modules, set a different kernel, or enter "boot -s" to continue into single user mode (where mounting / r/w and editing files using /rescue/vi would be possible). -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...