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=-7.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 1103EC43381 for ; Mon, 8 Feb 2021 14:48:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4DA864E6C for ; Mon, 8 Feb 2021 14:48:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233082AbhBHOr7 (ORCPT ); Mon, 8 Feb 2021 09:47:59 -0500 Received: from mail.xenproject.org ([104.130.215.37]:51080 "EHLO mail.xenproject.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232255AbhBHOgQ (ORCPT ); Mon, 8 Feb 2021 09:36:16 -0500 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; bh=aivOqaGOcSxpvU6conwQTcZ0h2NZKR4vLEU5lBoBLnM=; b=TpQqFHUGQ309Z3JMnbU0rIfpjj ASrKoC0dMPhuUjLk3ViAyPeqvknYbyMrlu/ppcR+upMwaNIxtxB5uhfH28LHUOellFyF5th0KdgHs jKTAv2UPTPD50GHhHJfMLTxTwKrTdbDlgJtHRIu8230PgEIb7ppiHtcCI8fRvPRQBvDo=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l97dF-0005YS-Lb; Mon, 08 Feb 2021 14:35:17 +0000 Received: from [54.239.6.177] (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 1l97dF-0007Co-Df; Mon, 08 Feb 2021 14:35:17 +0000 Subject: Re: [PATCH 0/7] xen/events: bug fixes and some diagnostic aids From: Julien Grall To: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-scsi@vger.kernel.org Cc: Boris Ostrovsky , Stefano Stabellini , stable@vger.kernel.org, Konrad Rzeszutek Wilk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Jens Axboe , Wei Liu , Paul Durrant , "David S. Miller" , Jakub Kicinski References: <20210206104932.29064-1-jgross@suse.com> <7aaeeb3d-1e1b-6166-84e9-481153811b62@suse.com> <6f547bb5-777a-6fc2-eba2-cccb4adfca87@xen.org> <0d623c98-a714-1639-cc53-f58ba3f08212@suse.com> <28399fd1-9fe8-f31a-6ee8-e78de567155b@xen.org> <1831964f-185e-31bb-2446-778f2c18d71b@suse.com> <199b76fd-630b-a0c6-926b-3e662103ec42@suse.com> <063eff75-56a5-1af7-f684-a2ed4b13c9a7@xen.org> <4279cab9-9b36-e83d-bd7a-ff7cd2832054@suse.com> <279b741b-09dc-c6af-bf9d-df57922fa465@xen.org> Message-ID: <9f07dae5-050c-da2c-edc1-e1587dbae9c4@xen.org> Date: Mon, 8 Feb 2021 14:35:14 +0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <279b741b-09dc-c6af-bf9d-df57922fa465@xen.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/02/2021 14:20, Julien Grall wrote: >>>> I believe this will be the case before our "lateeoi" handling is >>>> becoming active (more precise: when our IRQ handler is returning to >>>> handle_fasteoi_irq()), resulting in the possibility of the same race we >>>> are experiencing now. >>> >>> I am a bit confused what you mean by "lateeoi" handling is becoming >>> active. Can you clarify? >> >> See above: the next call of the handler should be allowed only after >> xen_irq_lateeoi() for the IRQ has been called. >> >> If the handler is being called earlier we have the race resulting >> in the WARN() splats. > > I feel it is dislike to understand race with just words. Can you provide Sorry I meant difficult rather than dislike. Cheers, -- Julien Grall