From owner-freebsd-current@freebsd.org Sat Jun 4 19:02:46 2016 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 97C4BB6ABB9 for ; Sat, 4 Jun 2016 19:02:46 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 162111A8A; Sat, 4 Jun 2016 19:02:45 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id u54J2bst091957 (version=TLSv1 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Sat, 4 Jun 2016 22:02:38 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua u54J2bst091957 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id u54J2bmB091956; Sat, 4 Jun 2016 22:02:37 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 4 Jun 2016 22:02:37 +0300 From: Konstantin Belousov To: Michael Butler Cc: Matthew Macy , "freebsd-current@freebsd.org" , alc@freebsd.org Subject: Re: repeatable panic on pageout with 945GM Message-ID: <20160604190237.GD38613@kib.kiev.ua> References: <2490f1c7-8153-ece3-49ed-4b3886564fd7@protected-networks.net> <205d4423-b834-9a21-785f-fa15d44c78ec@protected-networks.net> <1551419a1db.12929035f45012.326107747932338888@nextbsd.org> <939f9d2b-e925-e8e0-0ff3-8d90623728c6@protected-networks.net> <1551c5dbd86.c68532b5123717.566503881838650848@nextbsd.org> <20160604174745.GB38613@kib.kiev.ua> <88ad4228-2583-8a91-1751-d16f7a51de91@protected-networks.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <88ad4228-2583-8a91-1751-d16f7a51de91@protected-networks.net> User-Agent: Mutt/1.6.1 (2016-04-27) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Jun 2016 19:02:46 -0000 On Sat, Jun 04, 2016 at 02:59:01PM -0400, Michael Butler wrote: > On 06/04/16 13:47, Konstantin Belousov wrote: > > [ .. snip .. ] > > > I believe that this is a bug in amd64 pmap. Fictitious pages are not > > promoted, in particular, the pv_table array does not span over the > > dynamically registered fictitious ranges. As result, pa_to_pvh() returns > > garbage and pvh must not be accessed in the case of 'small_mappings' in > > several pmap functions. It is typically not accessed, except in case > > when we have to drop and reacquire pv lock, to avoid LOR with pmap. > > > > i386 does not have the issue, due to pvh_global_lock. > > > > Below is the supposed fix (not tested). > > [ .. snip .. ] > > Is this something I should test and, should it not introduce any other > issues, might get committed? Would be nice to test. I expect that this patch is going to be committed, after the review.