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Thu, 10 Apr 2025 14:48:37 +0000 (GMT) Message-ID: Date: Thu, 10 Apr 2025 20:18:36 +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] block: don't grab elevator lock during queue initialization To: Ming Lei Cc: Christoph Hellwig , Jens Axboe , linux-block@vger.kernel.org, syzbot+4c7e0f9b94ad65811efb@syzkaller.appspotmail.com References: <03ba309d-b266-4596-83aa-1731c6cc1cfb@linux.ibm.com> <5c2274c0-fd82-4752-b735-32e52de2a80f@linux.ibm.com> <917201e2-acac-4ab0-982e-04635806304c@linux.ibm.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 9PNRk16WkKR_wNB2gtxE73DX-TZz2hoK X-Proofpoint-ORIG-GUID: 9PNRk16WkKR_wNB2gtxE73DX-TZz2hoK X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-10_03,2025-04-10_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 impostorscore=0 priorityscore=1501 mlxlogscore=948 lowpriorityscore=0 spamscore=0 clxscore=1015 suspectscore=0 mlxscore=0 adultscore=0 bulkscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2502280000 definitions=main-2504100105 On 4/10/25 7:53 PM, Ming Lei wrote: > > I just sent out the whole patchset, which did one thing basically: move kobject > & debugfs & cpuhp out of queue freezing, then no any lockdep is observed in my > test VM after running blktests of './check block/'. Sure, I think our emails crossed over. I will review your changes. > > So the point is _not_ related with elevator lock or its order with > freeze lock. What matters is actually "do not connect freeze lock with > other subsystem(debugfs, sysfs, cpuhp, ...)", because freeze_lock relies > on fs_reclaim directly with commit ffa1e7ada456, but other subsystem easily > depends on fs_reclaim again. > > I did have patches to follow your idea to reorder elevator lock vs. freeze > lock, but it didn't make difference, even though after I killed most of > elevator_lock. > > Finally I realized the above point. Ok great:) Thanks, --Nilay