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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 5B77DC47247 for ; Thu, 30 Apr 2020 15:20:09 +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 2F35B20661 for ; Thu, 30 Apr 2020 15:20:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F35B20661 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 1jUAyi-0007sy-Fl; Thu, 30 Apr 2020 15:19:56 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jUAyh-0007st-1v for xen-devel@lists.xenproject.org; Thu, 30 Apr 2020 15:19:55 +0000 X-Inumbo-ID: 0a7cdab8-8af6-11ea-ae69-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 0a7cdab8-8af6-11ea-ae69-bc764e2007e4; Thu, 30 Apr 2020 15:19:53 +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 A26AFAF01; Thu, 30 Apr 2020 15:19:51 +0000 (UTC) Subject: Re: [PATCH 2/3] xen/sched: fix theoretical races accessing vcpu->dirty_cpu To: xen-devel@lists.xenproject.org References: <20200430151559.1464-1-jgross@suse.com> <20200430151559.1464-3-jgross@suse.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: <2bc16586-4937-9019-795d-9e54ea3e2c21@suse.com> Date: Thu, 30 Apr 2020 17:19:51 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200430151559.1464-3-jgross@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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: Stefano Stabellini , Julien Grall , Wei Liu , Andrew Cooper , Ian Jackson , George Dunlap , Jan Beulich , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 30.04.20 17:15, Juergen Gross wrote: > The dirty_cpu field of struct vcpu denotes which cpu still holds data > of a vcpu. All accesses to this field should be atomic in case the > vcpu could just be running, as it is accessed without any lock held > in most cases. > > There are some instances where accesses are not atomically done, and > even worse where multiple accesses are done when a single one would > be mandated. > > Correct that in order to avoid potential problems. > > Add some assertions to verify dirty_cpu is handled properly. > > Signed-off-by: Juergen Gross Please ignore this one, just realized it doesn't build for ARM. Juergen