From owner-freebsd-current Thu Feb 24 17:39:43 2000 Delivered-To: freebsd-current@freebsd.org Received: from sabre.velocet.net (sabre.velocet.net [198.96.118.66]) by hub.freebsd.org (Postfix) with ESMTP id 3395737BAA3 for ; Thu, 24 Feb 2000 17:39:37 -0800 (PST) (envelope-from dgilbert@velocet.ca) Received: from velocet.ca (trooper.velocet.net [216.126.82.226]) by sabre.velocet.net (Postfix) with ESMTP id 86164137FC5; Thu, 24 Feb 2000 20:39:26 -0500 (EST) Received: (from dgilbert@localhost) by velocet.ca (8.9.3/8.9.3) id UAA35457; Thu, 24 Feb 2000 20:39:47 -0500 (EST) (envelope-from dgilbert) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14517.56675.102218.408699@trooper.velocet.net> Date: Thu, 24 Feb 2000 20:39:47 -0500 (EST) To: Matthew Dillon Cc: Bruce Evans , David Gilbert , freebsd-current@FreeBSD.ORG Subject: Patch to try (was Re: Wierd AMD panics caused by VMWare?) In-Reply-To: <200002250033.QAA43662@apollo.backplane.com> References: <200002242105.NAA42378@apollo.backplane.com> <200002250033.QAA43662@apollo.backplane.com> X-Mailer: VM 6.75 under 20.4 "Emerald" XEmacs Lucid Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >>>>> "Matthew" == Matthew Dillon writes: Matthew> Please try the following patch and tell me if the crashes Matthew> still occur. If this fixes the problem then I'm homing in on Matthew> the bug. Matthew> I am beginning to suspect that there is a case where a Matthew> pmap can get cleared without the tlb being flushed, causing Matthew> origpte to be 0 when the new pte is later created again at Matthew> the same spot. When the new page is allocated and added to Matthew> the pmap later on, it fails to flush the tlb entry in Matthew> pmap_enter() because it believes it does not have to. Matthew> This would explain why messing with the pmap_remove_all() Matthew> case does not do what we expect -- I suspect that routine is Matthew> not being called at all in certain cases. Matthew> I have not found the case where the pmap gets cleared Matthew> without being flushed yet but when I force the flush in Matthew> pmap_enter(), it seems to stop the crashes (but I can't be Matthew> 100% sure because I had to mess around with that file Matthew> descriptor program to get it to crash the first time). So... to get this straight, you'd like us to back out that other patch and apply this one? I have to be honest that the machine that we have is only doing this once a month because we kept adding RAM to it until it stopped exhibiting the symptoms often. If it helps, it appears to us that 3.0 didn't have the problem and 3.2 did. Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://www.velocet.net/~dgilbert | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message