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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 C0FEEC4CEC9 for ; Tue, 17 Sep 2019 18:32:51 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 8802D2171F for ; Tue, 17 Sep 2019 18:32:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="yLz0Vc5U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8802D2171F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 3FE92B59; Tue, 17 Sep 2019 18:32:51 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id E03B2B50 for ; Tue, 17 Sep 2019 18:32:49 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-io1-f65.google.com (mail-io1-f65.google.com [209.85.166.65]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 3B57876D for ; Tue, 17 Sep 2019 18:32:49 +0000 (UTC) Received: by mail-io1-f65.google.com with SMTP id q1so10090202ion.1 for ; Tue, 17 Sep 2019 11:32:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=qNIe53zrgCg2gFdQMfvAbWjy6VVymIDFBP+9g5s+/5Y=; b=yLz0Vc5U1aO7M/ZcTpzpUb/M/FylLyeSzNkhWs6+dhbqe4TpVMHfVrI2BRMs0Pq6U7 T0p85T4alWTjJHm0Xojwq4P7cWFxs+OjlB/YaiWj9o1pcjKvw51aDzuO+VWqs+BA+wQK g9lwNzve5rdMUpYV5maaStxNBFaPM5sWl/dYLUjnPElt1jnpHrgX22V303IvfbYEr16x JYKGWb8xjTouEglYkck+LANfX05kEhv+ekMY0ASfwzk0ECLjdzzl36QZEZRz7m6H+qdf AmS3EVhaPjmF2ETJuekkDS2DGOIQYelXgQCX8dBScQJBoG/YgoFkJWoq3qe2EROuqzq0 KF2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=qNIe53zrgCg2gFdQMfvAbWjy6VVymIDFBP+9g5s+/5Y=; b=TyQOXnEMc2bgwYUBRSisROiyO3JczVKtfPUH7pMUrFOj5FnOfIJh7jQhanszGcN5Rr feadpg8/p29YECeHeVdpdTDqXQNAV0srUZnEzclC8PdHF1i4BP6q77FxB1AcD1bLtrz4 Yh+0JHF8ecZpPu/w9oDvMu7HtIaf+6Byjnph+9Wx9dL6jwNe953ZPnxRdTbQRF61LGj3 lUVwd8KYHj/lqXIOO0Z8cRpYJbrAztDNY8KYm+EIOFu2nw53dsHp6B0gDj4b1bzLAEkx kpmpnA7l3HAy9Vl7KNp8vSMESFFUTlGp8vS1UM4R78MD+33J/xYmFo3VCKCHoGFOiFRX O/pg== X-Gm-Message-State: APjAAAXPhsj9VRzHZEH5HPdQ+1MmLEZLJxlnCfHoY0Kf5jMN/59TkF5K MSHxxrEqmJWf/8YwosL5Pl8bzpkD5Z9vbA== X-Google-Smtp-Source: APXvYqxWUls28UFYxnGhX2kD5xZyHA3aFDkbk+EhHIwX49f2ds+U5AnNAiD7AeluDxPN3kHHkCXu0w== X-Received: by 2002:a6b:b487:: with SMTP id d129mr112912iof.223.1568745168066; Tue, 17 Sep 2019 11:32:48 -0700 (PDT) Received: from [192.168.1.50] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id m9sm890768ion.65.2019.09.17.11.32.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Sep 2019 11:32:47 -0700 (PDT) Subject: Re: [bug] __blk_mq_run_hw_queue suspicious rcu usage To: David Rientjes , Christoph Hellwig , Keith Busch References: <20190905060627.GA1753@lst.de> From: Jens Axboe Message-ID: <4cd700ef-f2fc-2bb5-35d2-0b2194accc45@kernel.dk> Date: Tue, 17 Sep 2019 12:32:45 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Cc: Tom Lendacky , Brijesh Singh , x86@kernel.org, linux-kernel@vger.kernel.org, Ming Lei , iommu@lists.linux-foundation.org, Peter Gonda , Jianxiong Gao X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On 9/17/19 12:23 PM, David Rientjes wrote: > On Mon, 16 Sep 2019, David Rientjes wrote: > >> Brijesh and Tom, we currently hit this any time we boot an SEV enabled >> Ubuntu 18.04 guest; I assume that guest kernels, especially those of such >> major distributions, are expected to work with warnings and BUGs when >> certain drivers are enabled. >> >> If the vmap purge lock is to remain a mutex (any other reason that >> unmapping aliases can block?) then it appears that allocating a dmapool >> is the only alternative. Is this something that you'll be addressing >> generically or do we need to get buy-in from the maintainers of this >> specific driver? >> > > We've found that the following applied on top of 5.2.14 suppresses the > warnings. > > Christoph, Keith, Jens, is this something that we could do for the nvme > driver? I'll happily propose it formally if it would be acceptable. No, this is not going to be acceptable, I'm afraid. This tells blk-mq that the driver always needs blocking context for queueing IO, which will increase latencies for the cases where we'd otherwise issue IO directly from the context that queues it. -- Jens Axboe _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu