From owner-freebsd-ia64 Tue Jan 7 1:24:48 2003 Delivered-To: freebsd-ia64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6247F37B401 for ; Tue, 7 Jan 2003 01:24:47 -0800 (PST) Received: from herring.nlsystems.com (mailgate.nlsystems.com [62.49.251.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4F24843E4A for ; Tue, 7 Jan 2003 01:24:46 -0800 (PST) (envelope-from dfr@nlsystems.com) Received: from herring.nlsystems.com (herring.nlsystems.com [10.0.0.2]) by herring.nlsystems.com (8.12.6/8.12.6) with ESMTP id h079OgOR008677; Tue, 7 Jan 2003 09:24:42 GMT (envelope-from dfr@nlsystems.com) Content-Type: text/plain; charset="iso-8859-1" From: Doug Rabson To: Marcel Moolenaar , Arun Sharma Subject: Re: unaligned fault in pmap_find_vhpt Date: Tue, 7 Jan 2003 09:24:42 +0000 User-Agent: KMail/1.4.3 Cc: freebsd-ia64@FreeBSD.ORG References: <200301032303.gBQJBOs00863@unix-os.sc.intel.com> <20030104043524.GA2059@dhcp01.pn.xcllnt.net> In-Reply-To: <20030104043524.GA2059@dhcp01.pn.xcllnt.net> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Message-Id: <200301070924.42508.dfr@nlsystems.com> X-Spam-Status: No, hits=-7.7 required=6.0 tests=IN_REP_TO,QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_00_01, USER_AGENT,USER_AGENT_KMAIL version=2.41 Sender: owner-freebsd-ia64@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Saturday 04 January 2003 4:35 am, Marcel Moolenaar wrote: > On Fri, Jan 03, 2003 at 03:03:14PM -0800, Arun Sharma wrote: > > I saw a kernel mode unaligned fault during a compilation workload > > yesterday on an SMP 5.0-RC1 kernel. The fault happened here: > > > > 0xe000000000aad660 : > > > > More info below. It looks like the pte_chain is getting corrupted > > somehow. What is the locking scheme being used to protect pte > > collision chains on an SMP kernel ? > > We don't really have a consistent locking scheme. We walk and > update the VHPT from IVA interrupt code as well. Under high > load, a SMP kernel corrupts process space. I haven't seen the > unaligned fault you mention. The IVA only updates the contents of the VHPT head entry (which is=20 always a copy of some element of the pte_chain). It never edits the=20 chain but I can see it getting confused if someone else edits the chain=20 while the IVA is walking it. --=20 Doug Rabson=09=09=09=09Mail: dfr@nlsystems.com =09=09=09=09=09Phone: +44 20 8348 6160 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-ia64" in the body of the message