From owner-freebsd-ia64@FreeBSD.ORG Wed Jul 8 11:49:32 2009 Return-Path: Delivered-To: freebsd-ia64@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3764C1065672; Wed, 8 Jul 2009 11:49:32 +0000 (UTC) (envelope-from mexas@bristol.ac.uk) Received: from dirj.bris.ac.uk (dirj.bris.ac.uk [137.222.10.78]) by mx1.freebsd.org (Postfix) with ESMTP id E2C9E8FC0C; Wed, 8 Jul 2009 11:49:31 +0000 (UTC) (envelope-from mexas@bristol.ac.uk) Received: from seis.bris.ac.uk ([137.222.10.93]) by dirj.bris.ac.uk with esmtp (Exim 4.69) (envelope-from ) id 1MOVeQ-0000SK-EK; Wed, 08 Jul 2009 12:49:30 +0100 Received: from mech-cluster238.men.bris.ac.uk ([137.222.187.238]) by seis.bris.ac.uk with esmtp (Exim 4.67) (envelope-from ) id 1MOVeP-0002D6-OX; Wed, 08 Jul 2009 12:49:26 +0100 Received: from mech-cluster238.men.bris.ac.uk (localhost.men.bris.ac.uk [127.0.0.1]) by mech-cluster238.men.bris.ac.uk (8.14.3/8.14.3) with ESMTP id n68BnPFQ019876; Wed, 8 Jul 2009 12:49:25 +0100 (BST) (envelope-from mexas@bristol.ac.uk) Received: (from mexas@localhost) by mech-cluster238.men.bris.ac.uk (8.14.3/8.14.3/Submit) id n68BnPq0019875; Wed, 8 Jul 2009 12:49:25 +0100 (BST) (envelope-from mexas@bristol.ac.uk) X-Authentication-Warning: mech-cluster238.men.bris.ac.uk: mexas set sender to mexas@bristol.ac.uk using -f Date: Wed, 8 Jul 2009 12:49:25 +0100 From: Anton Shterenlikht To: Marcel Moolenaar Message-ID: <20090708114925.GA19854@mech-cluster238.men.bris.ac.uk> References: <20090707094808.GA93317@mech-cluster238.men.bris.ac.uk> <20090707095058.GC7827@rink.nu> <20090707124405.GA46091@mech-cluster238.men.bris.ac.uk> <20090707133611.GA66072@rink.nu> <93B562A8-9FE7-44D5-91E4-C9AB1A25BD2A@mac.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <93B562A8-9FE7-44D5-91E4-C9AB1A25BD2A@mac.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-Spam-Score: -1.4 X-Spam-Level: - Cc: freebsd-current@freebsd.org, freebsd-ia64@freebsd.org Subject: Re: buildworld panic on ia64 X-BeenThere: freebsd-ia64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the IA-64 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Jul 2009 11:49:32 -0000 On Tue, Jul 07, 2009 at 05:29:06PM -0700, Marcel Moolenaar wrote: > > On Jul 7, 2009, at 6:36 AM, Rink Springer wrote: > >> I tried to reproduce the error, got this on the way: > >> > >> # XXX: bogusly disabled high FP regs > > > > I get this message quite often as well; I intend to figure out what's > > going on. Marcel, if you have any idea, please let me know. > > It's a race condition. The high FP registers are lazily > context-switched and this error is emitted when a thread > wants to use the high FP registers when they are disabled > and the CPU onto which the thread is running has the high > FP registers corresponding to that thread in registers. > In that scenario the high FP registers should not even be > disabled. > > In the above case the kernel simply enables the high FP > registers and continues the thread. For the most part the > condition is harmless, but I've been looking at a panic > that's the result of inconsistency in the high FP state, > so the race is potentially fatal. > > BTW: I never got the error when doing a buildworld. I > think Anton's non-standard compiler options make GCC much > more FP intensive and thus prone to causing the race. Marcel, sorry, I probably misunderstood "compiler options" in the previous reply. Did you mean -j option in make -j10 buildworld? -- Anton Shterenlikht Room 2.6, Queen's Building Mech Eng Dept Bristol University University Walk, Bristol BS8 1TR, UK Tel: +44 (0)117 928 8233 Fax: +44 (0)117 929 4423