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Tue, 28 Oct 2025 13:06:21 +0000 (GMT) Message-ID: <544b60be-376c-4891-95a4-361b4a207b8a@linux.ibm.com> Date: Tue, 28 Oct 2025 18:36:20 +0530 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REPORT] Possible circular locking dependency on 6.18-rc2 in blkg_conf_open_bdev_frozen+0x80/0xa0 To: Bart Van Assche , David Wei , linux-block@vger.kernel.org, cgroups@vger.kernel.org Cc: hch@lst.de, hare@suse.de, ming.lei@redhat.com, dlemoal@kernel.org, axboe@kernel.dk, tj@kernel.org, josef@toxicpanda.com, gjoyce@ibm.com, lkp@intel.com, oliver.sang@intel.com References: <63c97224-0e9a-4dd8-8706-38c10a1506e9@davidwei.uk> <5b403c7c-67f5-4f42-a463-96aa4a7e6af8@linux.ibm.com> <5c29fa84-3a2c-44be-9842-f0230e7b46dd@acm.org> Content-Language: en-US From: Nilay Shroff In-Reply-To: <5c29fa84-3a2c-44be-9842-f0230e7b46dd@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=fIQ0HJae c=1 sm=1 tr=0 ts=6900bfd4 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=PGCdswBLe-Oi2NptYxEA:9 a=QEXdDO2ut3YA:10 a=zZCYzV9kfG8A:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: 2BwY0Bm3qfLhk62aaeYB__bxQ_OJEtHC X-Proofpoint-GUID: 2BwY0Bm3qfLhk62aaeYB__bxQ_OJEtHC X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDI1MDAyNCBTYWx0ZWRfXwDiLLcg2bSMH 1glaaqGVuuVKUNkV+BE1FT5PB0yPDM5d32LRdRMFHIMry5p++gYI3NeObdvIxaJZPUNJKBW+tHf CsO3BzoDscLKZ17EDtH9x479Zn+UKxN6VhRMmI2mXda6A5ALpg5Bz1dNdrDPF06c3vaT0XJIdTb qYd45Mo5X/IiUi6ScPP2n2Vhy/llBYHcieGCR+atx79EndKf6aaHuEL2H3+57IlWPgeCdUoOOwo WncBl26n8fa9mHOpBR7XNNioeikBLmjkJ61bpchHicXdb9579XDCGncHo4dssifK3osN2QEgL+8 dgsyosQvQYidXb49zP97agmFM57Z28EXLUNu1hlWiazByqNUq20pQk3ffjcb8Ostg6r22CpQxIS osfqvBfyZbxSBFdGPxLNSZjVqul2VQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-28_04,2025-10-22_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 priorityscore=1501 adultscore=0 suspectscore=0 spamscore=0 clxscore=1015 bulkscore=0 lowpriorityscore=0 phishscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510020000 definitions=main-2510250024 On 10/28/25 2:00 AM, Bart Van Assche wrote: > On 10/23/25 9:54 PM, Nilay Shroff wrote: >> IMO, we need to make lockdep learn about this differences by assigning separate >> lockdep key/class for each queue's q->debugfs_mutex to avoid this false positive. >> As this is another report with the same false-positive lockdep splat, I think we >> should address this. >> >> Any other thoughts or suggestions from others on the list? > > Please take a look at lockdep_register_key() and > lockdep_unregister_key(). I introduced these functions six years ago to > suppress false positive lockdep complaints like this one. > Thanks Bart! I'll send out patch with the above proposed fix. Thanks, --Nilay