From owner-freebsd-current@freebsd.org Wed Dec 14 19:49:26 2016 Return-Path: Delivered-To: freebsd-current@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 BB321C8081D for ; Wed, 14 Dec 2016 19:49:26 +0000 (UTC) (envelope-from kargl@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "troutmask", Issuer "troutmask" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 9DFDD15F7; Wed, 14 Dec 2016 19:49:26 +0000 (UTC) (envelope-from kargl@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (localhost [127.0.0.1]) by troutmask.apl.washington.edu (8.15.2/8.15.2) with ESMTPS id uBEJnQrf001176 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 14 Dec 2016 11:49:26 -0800 (PST) (envelope-from kargl@troutmask.apl.washington.edu) Received: (from kargl@localhost) by troutmask.apl.washington.edu (8.15.2/8.15.2/Submit) id uBEJnQDF001175; Wed, 14 Dec 2016 11:49:26 -0800 (PST) (envelope-from kargl) Date: Wed, 14 Dec 2016 11:49:26 -0800 From: "Steven G. Kargl" To: freebsd-current@freebsd.org, markj@freebsd.org, kib@freebsd.org Subject: Revision 309657 to stack_machdep.c renders unbootable system Message-ID: <20161214194848.GA881@troutmask.apl.washington.edu> Reply-To: kargl@uw.edu MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.6.1 (2016-04-27) X-Mailman-Approved-At: Thu, 15 Dec 2016 00:53:51 +0000 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 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: Wed, 14 Dec 2016 19:49:26 -0000 Well, after 3 days of bisection, I finally found the commit that renders my system unbootable. The system does not panic. It simply gets stuck in some state. Nonfunctional keyboard, so can't break into debugger. No serial console available. The verbose dmesg.boot for a working kernel from revision 309656 is at http://troutmask.apl.washington.edu/~kargl/freebsd/dmesg.309656.txt The kernel config file is at http://troutmask.apl.washington.edu/~kargl/freebsd/SPEW.txt In looking at /usr/src/UPDATING, there is no warning that one can create a boat anchor by upgrading to 309657. If compiling a kernel with 'options DDB' is no longer supported, this should be stated in UPDATING. Or, UPDATING should state that 'options DDB' requires 'options STACK'. Or, 'options DDB' should simply to the right thing and pull in whatever 'option STACK' does. -- Steve http://troutmask.apl.washington.edu/~kargl/ https://www.youtube.com/watch?v=6hwgPfCcpyQ