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Fri, 10 Jul 2026 12:36:14 +0000 (GMT) Received: from [9.43.74.81] (unknown [9.43.74.81]) by smtpav05.wdc07v.mail.ibm.com (Postfix) with ESMTP; Fri, 10 Jul 2026 12:36:13 +0000 (GMT) Message-ID: Date: Fri, 10 Jul 2026 18:06:12 +0530 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V4 2/9] null_blk: register configfs subsystem after creating default devices To: Zizhi Wo , axboe@kernel.dk, dlemoal@kernel.org, kch@nvidia.com, johannes.thumshirn@wdc.com, kbusch@kernel.org, bvanassche@acm.org, linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org, yangerkun@huawei.com, chengzhihao1@huawei.com, wozizhi@huawei.com References: <20260709100452.3520482-1-wozizhi@huaweicloud.com> <20260709100452.3520482-3-wozizhi@huaweicloud.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20260709100452.3520482-3-wozizhi@huaweicloud.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=VebH+lp9 c=1 sm=1 tr=0 ts=6a50e744 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=ND1QlC8BqVg7SnU7v08A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: A2wz0WQxyEvBbhrsfpFql1uy89s518zY X-Proofpoint-ORIG-GUID: A2wz0WQxyEvBbhrsfpFql1uy89s518zY X-Proofpoint-Spam-Info: AW1haW4tMjYwNzEwMDEyMiBTYWx0ZWRfXwARQ/hrf+6GW jodV0851kSIzzwsp6YDu2h84u0Rvn9sG/VTF0DsqQFFVtnVQp0KrHFOcWGZRPAtaY8zGGo5XEdv OF1BYszHdcZG17oaApdvgEVeFeQoaDw= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzEwMDEyMiBTYWx0ZWRfX5YNj8Cxpd0bM 3Xth27nIeXHNltPXI3dgpcPBEUHgs28MXawIaWZzEonuU1RwRB1QnNsu6OcTgFKOr8KuZNbmUdN CEIufHz9BXay/XbOBn+W0cQz5Q/1PmoHFO+QsOVVendRhkRWirN5fSLt6n1/6CldcYVZZ0CRgmr oAZ6QoMQD87a1wIDxjB6eiK5EB3c1NoNICCMOcq1FggP+IlgAe+adlES8BZGdXPgvbkR3lr2ZIP R5HKGC+0rpJQVih3QWAo0Yaey4FZ/tEZQ3EPQ1ZAahkDlufddBm7rMPf+KHYCwDuH411FZzY4z4 SnJsNoAK6E7qoKJ0ju4qtSEjCN5dLseSgmsLav9Ta4fp4swOPmSw3ziNShTz4O5i/I44wsafDca 364pPHy+YnPmiKVYr5UJT+QEKywHDdUDF4KEEWIP9F0Cgj7P7dn0gAP9yrAXHWfCcZAzGUs+SfZ mGd9WkRJEwCj8XAMm/A== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-10_03,2026-07-09_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 suspectscore=0 clxscore=1015 malwarescore=0 impostorscore=0 phishscore=0 lowpriorityscore=0 adultscore=0 spamscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607100122 On 7/9/26 3:34 PM, Zizhi Wo wrote: > In null_init(), configfs_register_subsystem() currently runs before > register_blkdev(), so when null_blk is built as a module, a racing mkdir() > + poweron from userspace can reach null_add_dev() while null_major is still > 0. __add_disk() then hits WARN_ON(disk->minors) (major=0 with minors!=0) > and fails: Looks good to me. Reviewed-by: Nilay Shroff