From owner-cvs-src@FreeBSD.ORG Thu Sep 23 02:55:31 2004 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A003D16A4CE; Thu, 23 Sep 2004 02:55:31 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 25C8C43D2D; Thu, 23 Sep 2004 02:55:31 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [192.168.2.73] (cpe.125.wat.v126.packetworks.net [64.235.97.125] (may be forged)) (authenticated bits=0) by pooker.samsco.org (8.12.11/8.12.10) with ESMTP id i8N2tYni037548; Wed, 22 Sep 2004 20:55:34 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <41523ACB.8090707@samsco.org> Date: Wed, 22 Sep 2004 20:54:03 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.2) Gecko/20040831 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Alan Cox References: <200409220501.i8M51m8l009598@repoman.freebsd.org> In-Reply-To: <200409220501.i8M51m8l009598@repoman.freebsd.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=0.0 required=3.8 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on pooker.samsco.org cc: cvs-src@FreeBSD.org cc: src-committers@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/amd64/amd64 pmap.c src/sys/i386/i386 pmap.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Sep 2004 02:55:31 -0000 Alan Cox wrote: > alc 2004-09-22 05:01:48 UTC > > FreeBSD src repository > > Modified files: > sys/amd64/amd64 pmap.c > sys/i386/i386 pmap.c > Log: > Correct a long-standing error in _pmap_unwire_pte_hold() affecting > multiprocessors. Specifically, the error is conditioning the call to > pmap_invalidate_page() on whether the pmap is active on the current CPU. > This call must be unconditional. Regardless of whether the pmap is active > on the CPU performing _pmap_unwire_pte_hold(), it could be active on another > CPU. For example, a call to pmap_remove_all() by the page daemon could > result in a call to _pmap_unwire_pte_hold() with the pmap inactive on the > current CPU and active on another CPU. In such circumstances, failing to > call pmap_invalidate_page() results in a stale TLB entry on the other CPU > that still maps the now deallocated page table page. What happens next is > typically a mysterious panic in pmap_enter() by the other CPU, either > "pmap_enter: attempted pmap_enter on 4MB page" or "pmap_enter: pte vanished, > va: 0x%lx". Both occur because the former page table page has been recycled > and allocated to a new purpose. Consequently, it no longer contains zeroes. > > See also Peter's i386/i386/pmap.c revision 1.448 and the related e-mail > thread last year. > > Many thanks to the engineers at Sandvine for providing clear and concise > information until all of the pieces of the puzzle fell into place and > for testing an earlier patch. > > MT5 Candidate > > Revision Changes Path > 1.502 +6 -7 src/sys/amd64/amd64/pmap.c > 1.508 +5 -10 src/sys/i386/i386/pmap.c And thanks for your help too on this! Can I assume that this will be merged to RELENG_5? Scott