From owner-freebsd-hackers@FreeBSD.ORG Thu Sep 4 06:41:43 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2ABA416A4BF for ; Thu, 4 Sep 2003 06:41:43 -0700 (PDT) Received: from gandalf.online.bg (gandalf.online.bg [217.75.128.9]) by mx1.FreeBSD.org (Postfix) with SMTP id 6EE5643FCB for ; Thu, 4 Sep 2003 06:41:39 -0700 (PDT) (envelope-from roam@ringlet.net) Received: (qmail 12763 invoked from network); 4 Sep 2003 13:33:54 -0000 Received: from office.sbnd.net (HELO straylight.ringlet.net) (217.75.140.130) by gandalf.online.bg with SMTP; 4 Sep 2003 13:33:53 -0000 Received: (qmail 77469 invoked by uid 1000); 4 Sep 2003 13:12:45 -0000 Date: Thu, 4 Sep 2003 16:12:44 +0300 From: Peter Pentchev To: Don Bowman Message-ID: <20030904131244.GU556@straylight.oblivion.bg> Mail-Followup-To: Don Bowman , 'Mike Silbersack' , "'freebsd-hackers@freebsd.org'" References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="AkbCVLjbJ9qUtAXD" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.4i cc: "'freebsd-hackers@freebsd.org'" Subject: Re: non reliable nmi X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Sep 2003 13:41:43 -0000 --AkbCVLjbJ9qUtAXD Content-Type: text/plain; charset=windows-1251 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 04, 2003 at 09:16:23AM -0400, Don Bowman wrote: > > From: Mike Silbersack [mailto:silby@silby.com] > > On Thu, 28 Aug 2003, Don Bowman wrote: > >=20 > > > I have machdep.ddb_on_nmi=3D1. > > > I can drop into the debugger with the magic > > > key sequence. However, when i hit the NMI > > > jumper, i don't always go there. Sometimes > > > I do. > > > The system is 4-way SMP [2xHTT xeon processors] > > > with 4.7. > > > > > > Any suggestion on where my NMI might be going? > >=20 > > Is your NMI about 106K in size, and does it have the subjects=20 > > "Thank you", > > "Wicked screensaver" and others? If so, I think I know where it's > > going... >=20 > ? > it was actually a serious question. The nmi header on > my board goes into the ICH-3 of my chipset, but shorting the > jumper out doesn't always enter the debugger. It does > sometimes. If I set the NMI_NOW bit in the ICH-3 I always > enter the debugger. I was curious if anyone else had seen > this behaviour. I haven't kept quite up to date on my x86 hardware lately (read: in the past five to ten years), but I distinctly remember a time when everyone referred to x86's NMI as a joke: a non-maskable interrupt that anyone could mask using a simple CLI instruction. Not sure if this is still the case, others would have to say if today's processors still may get so wedged that a NMI request would simply be ignored. The other possibility is some kind of kernel mess-up, bad enough that an NMI does indeed reach the processor, the processor does invoke the NMI handler, yet the handler (DDB) is quite unable to actually do any useful work - messed up data structures and such. G'luck, Peter --=20 Peter Pentchev roam@ringlet.net roam@sbnd.net roam@FreeBSD.org PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553 This sentence no verb. --AkbCVLjbJ9qUtAXD Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) iD8DBQE/VzpM7Ri2jRYZRVMRAr7gAKC2n59BnE2gncwgQ0gGAKSOxNAxnwCgp4iE 2XLZcLw/PhsiWnJH/WxLurc= =wstU -----END PGP SIGNATURE----- --AkbCVLjbJ9qUtAXD--