Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 31 Mar 2022 19:24:16 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc:     Wenchao Hao <haowenchao@huawei.com>,
        syzkaller-bugs@googlegroups.com, axboe@kernel.dk,
        jejb@linux.ibm.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
        martin.petersen@oracle.com,
        syzbot+f08c77040fa163a75a46@syzkaller.appspotmail.com,
        linfeilong@huawei.com
Subject: Re: [PATCH] scsi: sd: call device_del() if device_add_disk() fails
Message-ID: <20220331162416.GI12805@kadam>
References: <20220329154948.10350-1-fmdefrancesco@gmail.com>
 <fdebdbd3-575b-b30e-d37f-dcc6d53a4f53@huawei.com>
 <20220331134210.GF12805@kadam>
 <1787706.atdPhlSkOF@leap>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1787706.atdPhlSkOF@leap>
User-Agent: Mutt/1.9.4 (2018-02-28)
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?iM2eOEd2BZ2UeUDvbJFYY86sstJ/sNEVN5dfU6tU+E+obINabc7d9bV1IIzY?=
 =?us-ascii?Q?v6fuzSc0x+LZlK+XZkWx7lvaV8FOk6eJLDCQEDe78cQvndwrp3FEdpDiaDgN?=
 =?us-ascii?Q?zQsB6JCh7nXwNKw7CYTnqaH+Xl1irUXqxTJ7r/POzDrBtmKzj1WKy03srAj/?=
 =?us-ascii?Q?d5pgqUssdZjSWnUcS1lcybqdwKV2TIUSF0Cio1kVq3PZVSGp2N0RrjXU2GUy?=
 =?us-ascii?Q?mKskQIB+Pp5S6Mz/ASdGP4KAsAVWijBpLNkq3HLhM/NjXHsfVYeUNhuKNKOv?=
 =?us-ascii?Q?jS2b5AQDMLTDqN1vN8LO3JxuAb9Gs1Y7Ll/lkg9X0KBjGL7UgtvzEqJ0OhMM?=
 =?us-ascii?Q?Dywg30Di/TXQ49w/joolLVZDHR4FjOX1zsyeMvHXArdP6tDv47kitrPWDaOF?=
 =?us-ascii?Q?/xb+f6DNGcKf73jgN8q1pfxfQVrsIb4UBURXp0iMYHlzDgIRfnMtDdR9iEt6?=
 =?us-ascii?Q?ecafZ1BnNvqFFy1rvkSlB7hSywoN22mrBjJu4ZEDZlRzk77M5BcrA6CfYbc+?=
 =?us-ascii?Q?SQIaWQ/eeMgbTifowmg5n7Y7Mcm6CjdQ7iAWQ1jqvV1pEjaWkTxUkl4ix69W?=
 =?us-ascii?Q?LbLl3LBpHbcW6z/67YPQCkQ9sWIXgXVR+i7ATlhsKbCudfHF+H5v9+Lecjco?=
 =?us-ascii?Q?L+GS/TDCIDHILt8k7LTV9ZZnjC4Z4tTvXVR1Y0TP3uIwQ4x+fgHZ4zhLaUR+?=
 =?us-ascii?Q?7Y2iGRIsPwxpHfMJwXmaXHg9URQCBg7csIxHAE0appISEpmVrkMYza0bcYAC?=
 =?us-ascii?Q?PgEnCCqRxv4bjockm7VU5Pzl+1/srdZu2FqoIosP/lrPFHtaLH3Fjv6C0qQv?=
 =?us-ascii?Q?8/LjyIqNUut3Et5EIoYnU2B1ZrsnVxEorRK8G6RbD46tAmRoM8m4s27MOr6L?=
 =?us-ascii?Q?rOcJf0e3qekXlvaIbsvpXZKKZSO90S0UHKwH/f3ineWRysvVCu6UuyPMhP1v?=
 =?us-ascii?Q?7OxSfr2CUBQIG3flPS4ZWk6D+LG7T6xqRwFhLH73e6TvbBkcisPIINQZ2lQp?=
 =?us-ascii?Q?fnzwcovpMcQyBLziMEIZKwpItCw3K6S978aUEGHfM8zHZ5oSoyGfctn19TJ9?=
 =?us-ascii?Q?DQhX76TlOnoYXoQFOdj+htJs04RvMBB3J1dp+9yJalw9aLJTWjZB4yJgUbjf?=
 =?us-ascii?Q?/BN6KJHlpkt8pMXdNFUD0PcjuaTJuRWIDN9i/ymy71hSZfAIUC7k+e0c2eIa?=
 =?us-ascii?Q?1kPZtxibZi5FxcZVDnGt/72c12+Gh/w86URg63Yzft4SXoOYGiCyeS+I6MIP?=
 =?us-ascii?Q?mYHw4jnF1vJtSdwsS/00QFwTBhp/ERnRnTnfRuiTPiCJoddeafxoa8+s5rDT?=
 =?us-ascii?Q?lGsyDcXRzDHS0Gg2+yS8YiTKYWnGMNqUu8xqJY42UjmWl65ulisftZoCYM0l?=
 =?us-ascii?Q?AeTqvi6QU3TgSQCsd7yqzERJKDEbG7GhzCnY5WCOh6BF5VGhOW5j7NnUfP1O?=
 =?us-ascii?Q?Fmmyz5u6dnp1ArWn9/NUKtIoBJm3DfgNQY5fkA+xBty/YBxnPA3+UUQll74j?=
 =?us-ascii?Q?4crRFqqwHWxnbQvC9Q4itQAFw0vRIRC2OtYCvDcAqyJwOgw2LxC/6d+Hz8Kc?=
 =?us-ascii?Q?zR9Q+R87UPPVAY0YCta1Wqr8Xpq4FdB85ccm/RV2h04NQADozWFsGwRZ4CQQ?=
 =?us-ascii?Q?8wjZlpeXfbX69s/+28tpvjuu0NmkSz4gZC5j3WjA9kysYNYgSS2XI6QW0/M6?=
 =?us-ascii?Q?9NmLBFbZxD9VDyccz2oj8qn+AzwWV992LDYvVHCBv16Vb+7Y0hVS96IttzEG?=
 =?us-ascii?Q?eJZ9IE/dT/kvXvPdkCN944njYIInMXM=3D?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 6ac9266e-f168-4390-ad3c-08da1332f614
X-MS-Exchange-CrossTenant-AuthSource: MWHPR1001MB2365.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 Mar 2022 16:24:42.9657
 (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: c9VWKN9ggo+HbWnGZp2zUazhcc36W2YNBPk35Fk6Ax8R0Np0KXh3EJ4GjiLWFO95q9yO3Zd4OwUrU7hVyOWTOPPxAi6H4uVWMzwwBTuuKrE=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR10MB5870
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.425,18.0.850
 definitions=2022-03-31_05:2022-03-30,2022-03-31 signatures=0
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxlogscore=999
 phishscore=0 malwarescore=0 bulkscore=0 suspectscore=0 adultscore=0
 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2202240000 definitions=main-2203310090
X-Proofpoint-GUID: EP6NiaObFWaMerlAqXFDaT492otoLsy4
X-Proofpoint-ORIG-GUID: EP6NiaObFWaMerlAqXFDaT492otoLsy4
X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,
        T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Mar 31, 2022 at 06:14:27PM +0200, Fabio M. De Francesco wrote:
> On gioved? 31 marzo 2022 15:42:10 CEST Dan Carpenter wrote:
> > Wenchao Hao, what you're saying makes a lot of sense but it raises a lot
> > of questions in turn.
> > 
> > Fabio, did you test your patch?
> 
> Yes, I did, Dan. I tested it the usual way with the "#syz test:" command.
> Obviously I have not the hardware to test code on it.
> 

Yeah.  What a nightmare.  You posted a link to the first test.  It said
passed but definitely introduced some use after frees but how was anyone
supposed to know?

No way we would have figured this out.  I'm working to make Smatch
understand device_put() better but this one is way difficult.

Sorry that you went through this.

regards,
dan carpenter