From owner-freebsd-stable@FreeBSD.ORG Wed Jun 28 23:54:04 2006 Return-Path: X-Original-To: freebsd-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 1607F16A47B for ; Wed, 28 Jun 2006 23:54:04 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2211A448E4 for ; Wed, 28 Jun 2006 22:57:59 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 4013246C00; Wed, 28 Jun 2006 18:57:58 -0400 (EDT) Date: Wed, 28 Jun 2006 23:57:58 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: User Freebsd In-Reply-To: <20060628193421.B43909@ganymede.hub.org> Message-ID: <20060628235640.A78211@fledge.watson.org> References: <20060628175839.F43909@ganymede.hub.org> <20060628232727.N78211@fledge.watson.org> <20060628193421.B43909@ganymede.hub.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-stable@freebsd.org Subject: Re: How to enter DDB through a terminal server / remote console ... ? 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: Wed, 28 Jun 2006 23:54:04 -0000 On Wed, 28 Jun 2006, User Freebsd wrote: > On Wed, 28 Jun 2006, Robert Watson wrote: > >> On Wed, 28 Jun 2006, User Freebsd wrote: >> >>> 'k, now that I'm up to 3 6-STABLE servers that are deadlocking, I'm >>> spending time with the remote tech today to get a serial console put >>> online ... how do I drop into DDB remotely, where the serial console is >>> going through a Portmaster Terminal server? issuing CTL-ALT-ESC, I doubt, >>> will work, will it? >> >> If configured to use a serial console (console="comconsole" in >> loader.conf), you can enter the debugger with BREAK_TO_DEBUGGER in the >> kernel config by sending a serial break. With my portmasters, I telnet to >> a TCP port to connect to the serial console, so I send a telnet break, >> using ^]send break. > > Have you ever had a problem with this warning: "(useful for remote > diagnostics, but also dangerous if you generate a spurious BREAK on the > serial port!)" in the handbook? Yes. It's unusual, but once in a while I get a nervous serial port. If you experience this, type "Cont" to continue, and then recompile your kernel with ALT_BREAK_TO_DEBUGGER but without BREAK_TO_DEBUGGER. Here's the notes entry: # Solaris implements a new BREAK which is initiated by a character # sequence CR ~ ^b which is similar to a familiar pattern used on # Sun servers by the Remote Console. options ALT_BREAK_TO_DEBUGGER I've not had problem a problem on any recent hardware except for my soekris. Robert N M Watson Computer Laboratory University of Cambridge