From owner-freebsd-hackers Fri Mar 14 14:09:12 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id OAA14762 for hackers-outgoing; Fri, 14 Mar 1997 14:09:12 -0800 (PST) Received: from rocky.mt.sri.com (rocky.mt.sri.com [206.127.76.100]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id OAA14754 for ; Fri, 14 Mar 1997 14:09:09 -0800 (PST) Received: (from nate@localhost) by rocky.mt.sri.com (8.7.5/8.7.3) id PAA07831; Fri, 14 Mar 1997 15:08:47 -0700 (MST) Date: Fri, 14 Mar 1997 15:08:47 -0700 (MST) Message-Id: <199703142208.PAA07831@rocky.mt.sri.com> From: Nate Williams MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: Bakul Shah Cc: hackers@freebsd.org Subject: Re: kernel remote debugging using gdb In-Reply-To: <199703142053.PAA00554@chai.plexuscom.com> References: <199703142053.PAA00554@chai.plexuscom.com> Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > What I did: > > - recompiled the boot program to always use COM1 as console and > installed it on the primary disk on the test machine (called TEST). > > - used the following options in the TEST config file: > options COMCONSOLE You don't need COMCONSOLE for this to work, as a matter of fact you really don't want it due to the problems you've outlined below. > There are two problems: > > - Sendind a break in multiuser mode (before or after attaching gdb) > does not seem to drop the kernel in the debugger. This seems to > work occasionally but I haven't as yet figured out under what > conditions. I suspect the break is lost. If you aren't using the COMCONSOLE, do it on the real console. > - In single user mode when gdb is attached, you can not type anything > on the console nor can you see any printf() output[1]. That's because trying to MUX the gdb connection and the console is not a good idea. Serial debugging should not be attempted for remote connections simply because you can hang yourself. Nate