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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D7C29C4707D for ; Fri, 21 May 2021 20:00:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3CBF613EA for ; Fri, 21 May 2021 20:00:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230062AbhEUUCC (ORCPT ); Fri, 21 May 2021 16:02:02 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:43962 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229808AbhEUUCA (ORCPT ); Fri, 21 May 2021 16:02:00 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 14LJwXmS104437; Fri, 21 May 2021 20:00:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=to : cc : subject : from : message-id : references : date : in-reply-to : content-type : mime-version; s=corp-2020-01-29; bh=HEzZYQOQNs/EemiuBbuqHRFmDacodgmX7QI+zctPI/4=; b=hj/qAeDwZJY4LFoaTF7IrRCrY/XbvSzKQ9526ShPnlT4nTy6nP2IOC/qqBByvejv40At fdySdnx2/m6rwglH/QFFEq83yYHwYc6nwOlqZhmH0WABOpPxuItGclvKxjOnIsor6Yqf zGbss3xKQlpgC2TVmH6eN/NV8uVijJD6inw80DKIKn0SDNmG6vJ6PWuihtWRHvHRTR3F qI2poY3ZAuITOYIsVFm6cjq+ZZTsPPfl6145Rki/wqtKfTrRD1YXI7x9SUF0yzfPasLf s/ZKRNNjws0iI2EFKdGGct/P55PA6fnv8SPHszyDXCGoe+e/5Xn2snq8fU3sSaqmGRW7 uw== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2130.oracle.com with ESMTP id 38j3tbrqje-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 21 May 2021 20:00:32 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 14LK0Lhl097039; Fri, 21 May 2021 20:00:32 GMT Received: from nam10-mw2-obe.outbound.protection.outlook.com (mail-mw2nam10lp2102.outbound.protection.outlook.com [104.47.55.102]) by aserp3020.oracle.com with ESMTP id 38nry3prf1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 21 May 2021 20:00:31 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=XxnpKjUxzqkAW4BOepNDtjrItluaBbZlDtolJd+aLQqXYslcSsMwzCeYsUlXt/gXXYZ4KcQMrcyICSou7wmp76tAHlsAxV5xo0s2JKRQ8IpNDVXfUqMvxihJDwz0eq73FInjDDSAvG3I3CTw3f4HjjlO6KELisfGt5AIkIvQoDkUo5qlD/bF/c1sIZGsPrN4/dCAMJHNbw/8v+bXhvg+vC+dXte14ENWAyRg5iuZOTYXTkmo1WMJOI3IjlyyZVkiCJ7T9KfUb5vfyZnrP5rPCbUsuNOUomMO45B3DKbYNSlKUguP3MwJ/++l1SXRAcLotxdAZKK3HveLtBaphCPB8w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=HEzZYQOQNs/EemiuBbuqHRFmDacodgmX7QI+zctPI/4=; b=BVAw6iu39SruoUJ1nanV+wHsBcxUi0W0c7lifcsCknlWUmU5Mu6a7koik3uzwjgvqdrGL3CA1jV0ixccBvJDBnu106/veO9c6fjAJo6qtp/KWllhPpwTFnl9uI1R/8t9lyya1zCtUuJtCaTcNUBpR1wCJxBCItdaq/r+DrIybkkOMpgwro3PPRrfFHANi8vbOKZcjq0ZUIRAow/otptp278U4ToEPcJx89VdYv+Xcw7i5vCboPAsIFMfJ0TswOFc1yZ9nD9S7kmDpg4LYpBddxGxbp/6YUhv8AmtNwhbko/YTovhjp8sIpz/ywti9rIggd3zrsqJT0VxUSJ/QqCCzw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=HEzZYQOQNs/EemiuBbuqHRFmDacodgmX7QI+zctPI/4=; b=FCv1E0BfrNOO8gIl6jvrKZlSsjXlUe7rMLGIEwjG3+btDjMzNg7Aezr3ynoWMgSqwowaC+Le8p1Apdyzfs5Rn4/EBm0fsMP+DUPB/hW8D/wwGRT/GgyLRXUv5grL9+J/P+Md2CjZMtGtr8FDCaroLD96If5m8aMaTNdOlSWE0NM= Authentication-Results: philpotter.co.uk; dkim=none (message not signed) header.d=none;philpotter.co.uk; dmarc=none action=none header.from=oracle.com; Received: from PH0PR10MB4759.namprd10.prod.outlook.com (2603:10b6:510:3d::12) by PH0PR10MB4776.namprd10.prod.outlook.com (2603:10b6:510:3f::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4150.23; Fri, 21 May 2021 20:00:14 +0000 Received: from PH0PR10MB4759.namprd10.prod.outlook.com ([fe80::4c61:9532:4af0:8796]) by PH0PR10MB4759.namprd10.prod.outlook.com ([fe80::4c61:9532:4af0:8796%7]) with mapi id 15.20.4150.023; Fri, 21 May 2021 20:00:14 +0000 To: Phillip Potter Cc: jejb@linux.ibm.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] scsi: sd: skip checks when media is present if sd_read_capacity reports zero From: "Martin K. Petersen" Organization: Oracle Corporation Message-ID: References: <20210506073610.33867-1-phil@philpotter.co.uk> Date: Fri, 21 May 2021 16:00:10 -0400 In-Reply-To: <20210506073610.33867-1-phil@philpotter.co.uk> (Phillip Potter's message of "Thu, 6 May 2021 08:36:10 +0100") Content-Type: text/plain X-Originating-IP: [138.3.200.58] X-ClientProxiedBy: SA0PR11CA0092.namprd11.prod.outlook.com (2603:10b6:806:d1::7) To PH0PR10MB4759.namprd10.prod.outlook.com (2603:10b6:510:3d::12) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from ca-mkp.ca.oracle.com (138.3.200.58) by SA0PR11CA0092.namprd11.prod.outlook.com (2603:10b6:806:d1::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4150.23 via Frontend Transport; Fri, 21 May 2021 20:00:13 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 10b7bd28-3fea-420a-7bf8-08d91c930c3b X-MS-TrafficTypeDiagnostic: PH0PR10MB4776: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR10MB4759.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(396003)(366004)(39860400002)(376002)(136003)(346002)(8676002)(16526019)(36916002)(2906002)(66556008)(66946007)(66476007)(4744005)(478600001)(26005)(7696005)(966005)(956004)(52116002)(5660300002)(86362001)(186003)(8936002)(6916009)(38100700002)(55016002)(38350700002)(316002)(4326008)(83380400001)(99710200001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?Ey1TDn/dSe6t0fudbIzb58FvMtkuLDJ9ZL056ZrEmp/2MlIkDd3JOzE+Qap3?= =?us-ascii?Q?ITzAe3d4fOosmgxnX+RFvQ9x3anU6g6IxC6F70DDKMO5QX3OMPADyUpMJanb?= =?us-ascii?Q?kzV9+TISl1jx4V4LHZRkeB7864zdOqIT9gJ5oWiTOOLFBRgV6uepGl56yWZJ?= =?us-ascii?Q?hBs5boom6ZeLYeEsOnt8l4JYP0R5BSXLNSmn8hjMp3haU1WQDSVzYiOQjTGU?= =?us-ascii?Q?MozSMONj3Kcdg469ST78ve25YCd7Wg4WFIZzTiUGZEhUMQUeDqTly/GTNt6v?= =?us-ascii?Q?LzkQXRumFC9LbavcbRIORCSNbZFZdglXWIoughV8GKC1XugSiIqjUzyVcPD0?= =?us-ascii?Q?SPWo1E3KrddC6hCiW/fawOCDNDTayj5lC1dIpag1apXrZVLCRV/626Lbcfx3?= =?us-ascii?Q?IgS1fqgKLcrZWFbi4DhUpeIgNe2LHf3OlzKoTd+MI2zIjb3e8T+fql9z1XY+?= =?us-ascii?Q?Zn8LMwsTuzDh+JFnWmkn/6WPW1ZjnCt5RNNz8mJimn/rhmaPuSRKyJ53diVw?= =?us-ascii?Q?u8J/WFm/2GFIhDWTMkjTm+CLA9gTE0RBly+CiyZHfnt7WYp9C1ju0ar7pGtv?= =?us-ascii?Q?A6xgC8R6Pe+KBVv1uzervDN47sj3I6p2ppnl/JxnCEn/1v3ylUKm2Iwf1edj?= =?us-ascii?Q?gUG/w22/r2UG+wtX3lC3tVIm/VKGvENXW7YvWPHAjPljr7sO+xuOsA/M2dLY?= =?us-ascii?Q?HnsIJFTEHJlGhAlM6z4Xs27w6nAqzvpVgAdlkGrLpwZv9ijBUpIctflyRTtc?= =?us-ascii?Q?PZej+n/Zfg9s0nqz3Gs8/UC4UCNvJnaYEijJ4BuqUle7hsn52K7L2MFTo665?= =?us-ascii?Q?CkxtZE1jXAwMIclFbMjLTP29iwtMWShvrWQiH/mdkEeH9Rt/dioDF1GdAMS0?= =?us-ascii?Q?Cc2jTnZK5LrWNZI0Lb29EyJjPN6NAs6dfLwe2KZ9r3r5VqsJWPFEbAKZTsU1?= =?us-ascii?Q?rjpPbuVPXTLsDFuVquPKXhRq9QRCn+2Dh4JEuTUyeYcL63Ya4uxzIBwpj3Q/?= =?us-ascii?Q?kKDOALoO99HBeXYPn5EbYRmNLQoioSnb7FHGJgW78WZQt/kl83VvUz+tCT0j?= =?us-ascii?Q?1jVJ56osb6PbFKefgEV+ZTagV2ksMctNnK/G8/k0sY3mRqd3RVg8wD8aoT6Q?= =?us-ascii?Q?Grs2e0SmWNpT7k+toAwSR7F3MDHLXEVNbCSKaI5HmbHBV6qm4CJoXTSxOTk3?= =?us-ascii?Q?6TIQdyYMEMfn9yKfgspA2d2NcvrolC56RgQy7oHK7kUci7r8DIDmJ4hL4zeZ?= =?us-ascii?Q?GwWPRi9PWmIppsfOkap7+ObAmnSle7f/anWKUzlO5dprlmU65LUOuY5TEhT7?= =?us-ascii?Q?T86rJc/yMFpXYYCVPEhd/ZqW?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 10b7bd28-3fea-420a-7bf8-08d91c930c3b X-MS-Exchange-CrossTenant-AuthSource: PH0PR10MB4759.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 May 2021 20:00:14.1417 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 4EIvMs8IkJCIYebvS3uhzg1FLhP9t4FdCJp9X0YIm9ApaXMzhqrnpsSVx5GLGbS+PsbiLspUoWJbIKE7rmXslo9KDcukcm6SJM9jNfgEpQQ= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR10MB4776 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9991 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 suspectscore=0 malwarescore=0 mlxlogscore=999 adultscore=0 mlxscore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105210107 X-Proofpoint-ORIG-GUID: J3t4oxWIIqHT7bAZaS5LRwBmQsxO7hmu X-Proofpoint-GUID: J3t4oxWIIqHT7bAZaS5LRwBmQsxO7hmu X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9991 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 malwarescore=0 spamscore=0 priorityscore=1501 suspectscore=0 mlxlogscore=999 mlxscore=0 impostorscore=0 adultscore=0 clxscore=1011 phishscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105210107 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hello Phillip! > In sd_revalidate_disk, if sdkp->media_present is set, then sdkp->capacity > should not be zero. Therefore, jump to end of if block and skip remaining > checks/calls. Fixes a KMSAN-found uninit-value bug reported by syzbot at: > https://syzkaller.appspot.com/bug?id=197c8a3a2de61720a9b500ad485a7aba0065c6af The reported read of an uninitialized value is in scsi_mode_sense() while inspecting a buffer returned from sending a MODE SENSE command to the device. The buffer in question is memset() before executing the MODE SENSE command. And we only look at the buffer contents if the MODE SENSE operation was successful. As far as I can tell the only way to end up reading uninitialized data is if the device successfully completes the command but fails to transfer the data buffer. But maybe I'm missing something? -- Martin K. Petersen Oracle Linux Engineering