From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3828BC433DF for ; Fri, 15 May 2020 09:47:20 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 09C49206B6 for ; Fri, 15 May 2020 09:47:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 09C49206B6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jZWvE-0000lS-Dw; Fri, 15 May 2020 09:46:28 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jZWvC-0000lN-MB for xen-devel@lists.xenproject.org; Fri, 15 May 2020 09:46:26 +0000 X-Inumbo-ID: f1343dc0-9690-11ea-ae69-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id f1343dc0-9690-11ea-ae69-bc764e2007e4; Fri, 15 May 2020 09:46:25 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 26800AD31; Fri, 15 May 2020 09:46:27 +0000 (UTC) Subject: Re: [PATCH v2 4/6] x86/mem-paging: add minimal lock order enforcement to p2m_mem_paging_prep() To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <4af1f459-fe7a-cd61-43cb-fb3fa4f15c00@suse.com> <20200514162545.GI54375@Air-de-Roger> From: Jan Beulich Message-ID: <8b9fd4ce-177f-6f57-8d24-8468fea0c299@suse.com> Date: Fri, 15 May 2020 11:46:23 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200514162545.GI54375@Air-de-Roger> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: "xen-devel@lists.xenproject.org" , George Dunlap , Wei Liu , Andrew Cooper Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 14.05.2020 18:25, Roger Pau Monné wrote: > On Thu, Apr 23, 2020 at 10:38:44AM +0200, Jan Beulich wrote: >> While full checking is impossible (as the lock is being acquired/ >> released down the call tree), perform at least a lock level check. > > I'm slightly confused, doesn't alloc_domheap_page already have it's > own lock order checking? I don't see how it would, as it doesn't (and can't legitimately) include arch/x86/mm/mm-locks.h. Also maybe this comment in the header clarifies it: /* Page alloc lock (per-domain) * * This is an external lock, not represented by an mm_lock_t. However, * pod code uses it in conjunction with the p2m lock, and expecting * the ordering which we enforce here. * The lock is not recursive. */ Jan