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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 0F41BC43461 for ; Mon, 17 May 2021 14:13:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9361613DD for ; Mon, 17 May 2021 14:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236950AbhEQOOy (ORCPT ); Mon, 17 May 2021 10:14:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:50832 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238408AbhEQOMX (ORCPT ); Mon, 17 May 2021 10:12:23 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1621260665; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EHKWqf4XFF6yDcLUh1zTWK08SLSurVXp3htCEcxP5vE=; b=E/smndzrybtZpCiCz9AUTl7jnNh2pkguz/VZt6nPJHhKIgSHg5e+tw9ARnJDn1EcyK2+cn lFybTRXBH2ocNsv/+wp+GGviqEPear+M6xfRObO9q4jdTFrboawxEbyCMWSdUqoavyooLm QhEcb3OMdpcAQwB8NU5o7YmQaot/KFs= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id B3985B226; Mon, 17 May 2021 14:11:05 +0000 (UTC) Subject: Re: [PATCH 4/8] xen/blkfront: don't trust the backend response data blindly To: Juergen Gross Cc: Konrad Rzeszutek Wilk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Boris Ostrovsky , Stefano Stabellini , Jens Axboe , xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210513100302.22027-1-jgross@suse.com> <20210513100302.22027-5-jgross@suse.com> From: Jan Beulich Message-ID: <315ad8b9-8a98-8d3e-f66c-ab32af2731a8@suse.com> Date: Mon, 17 May 2021 16:11:05 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210513100302.22027-5-jgross@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 13.05.2021 12:02, Juergen Gross wrote: > @@ -1574,10 +1580,16 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) > spin_lock_irqsave(&rinfo->ring_lock, flags); > again: > rp = rinfo->ring.sring->rsp_prod; > + if (RING_RESPONSE_PROD_OVERFLOW(&rinfo->ring, rp)) { > + pr_alert("%s: illegal number of responses %u\n", > + info->gd->disk_name, rp - rinfo->ring.rsp_cons); > + goto err; > + } > rmb(); /* Ensure we see queued responses up to 'rp'. */ I think you want to insert after the barrier. > @@ -1680,6 +1707,11 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) > spin_unlock_irqrestore(&rinfo->ring_lock, flags); > > return IRQ_HANDLED; > + > + err: > + info->connected = BLKIF_STATE_ERROR; > + pr_alert("%s disabled for further use\n", info->gd->disk_name); > + return IRQ_HANDLED; > } Am I understanding that a suspend (and then resume) can be used to recover from error state? If so - is this intentional? If so in turn, would it make sense to spell this out in the description? Jan