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=-6.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 2B26DC433E0 for ; Thu, 30 Jul 2020 18:29:35 +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 EBBDE20829 for ; Thu, 30 Jul 2020 18:29:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="o8sSf9Ib" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBBDE20829 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org 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 1k1DIm-0004Ua-RO; Thu, 30 Jul 2020 18:29:12 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1DIl-0004UV-6A for xen-devel@lists.xenproject.org; Thu, 30 Jul 2020 18:29:11 +0000 X-Inumbo-ID: 8f80f134-d292-11ea-ab04-12813bfff9fa Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 8f80f134-d292-11ea-ab04-12813bfff9fa; Thu, 30 Jul 2020 18:29:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:References:Cc:To:From:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=Q4jCjAO8LHhj2w0cFfnko4lzoObkmN5toQK4yl73xGc=; b=o8sSf9IbWuy2BII5b7rbhHlzEO FzSvAWdrcuSRp86jcdwedoZuqzgEBvoiZbbBLFgImofhiLvVgg8smP0J4xpZuw6hdoNeQ0HaQ/iEr vnxnGMpOIHjrn7J/kpKX64yCmDCMOMoNnBHpYYwTg46mReYhVYVcb1VrPj/evsQIiKTg=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1DIi-000834-D9; Thu, 30 Jul 2020 18:29:08 +0000 Received: from 54-240-197-226.amazon.com ([54.240.197.226] helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1k1DIi-0007FT-2l; Thu, 30 Jul 2020 18:29:08 +0000 Subject: Re: [PATCH] xen/spinlock: move debug helpers inside the locked regions From: Julien Grall To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <20200729111330.64549-1-roger.pau@citrix.com> <16dd0f04-598b-8b84-8a25-6b89af9214d7@xen.org> <20200729135045.GD7191@Air-de-Roger> Message-ID: <1e48ae9c-c335-69cc-1d26-ac4a0b74c4e8@xen.org> Date: Thu, 30 Jul 2020 19:29:05 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB 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: Igor Druzhinin , Stefano Stabellini , Wei Liu , Andrew Cooper , Ian Jackson , George Dunlap , Jan Beulich , xen-devel@lists.xenproject.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 29/07/2020 15:57, Julien Grall wrote: > Hi Roger, > > On 29/07/2020 14:50, Roger Pau Monné wrote: >> On Wed, Jul 29, 2020 at 02:37:44PM +0100, Julien Grall wrote: >>> Hi Roger, >>> >>> On 29/07/2020 12:13, Roger Pau Monne wrote: >>>> Debug helpers such as lock profiling or the invariant pCPU assertions >>>> must strictly be performed inside the exclusive locked region, or else >>>> races might happen. >>>> >>>> Note the issue was not strictly introduced by the pointed commit in >>>> the Fixes tag, since lock stats where already incremented before the >>>> barrier, but that commit made it more apparent as manipulating the cpu >>>> field could happen outside of the locked regions and thus trigger the >>>> BUG_ON. >>> >>>  From the wording, it is not entirely clear which BUG_ON() you are >>> referring >>> to. I am guessing, it is the one in rel_lock(). Am I correct? >> >> Yes, that's right. Expanding to: >> >> "...  and thus trigger the BUG_ON in rel_lock()." would be better. > > Looks good to me. With that: > > Reviewed-by: Julien Grall > > I am happy to do the update on commit if there is no more comments. Committed. Thank you! Cheers, -- Julien Grall