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Sun, 4 Jan 2026 16:39:31 +0000 (GMT) Message-ID: <550b4282-9850-48b3-8428-4519c68ca5af@linux.ibm.com> Date: Sun, 4 Jan 2026 22:09:30 +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 v7 11/16] blk-wbt: fix incorrect lock order for rq_qos_mutex and freeze queue To: Yu Kuai , axboe@kernel.dk, linux-block@vger.kernel.org, tj@kernel.org, ming.lei@redhat.com References: <20251231085126.205310-1-yukuai@fnnas.com> <20251231085126.205310-12-yukuai@fnnas.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20251231085126.205310-12-yukuai@fnnas.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=QbNrf8bv c=1 sm=1 tr=0 ts=695a97c8 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=tJLSzyRPAAAA:8 a=VnNF1IyMAAAA:8 a=sVn0Sq3BUQtChHf1ZOIA:9 a=QEXdDO2ut3YA:10 a=ZXulRonScM0A:10 a=H0xsmVfZzgdqH4_HIfU3:22 X-Proofpoint-ORIG-GUID: Y1yDetNcfr3Gg7pP3U8jRIytjo97cbE0 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTA0MDE1MSBTYWx0ZWRfX48gL8UbJ+T1x FneRQEs4FGCiw5ikjXx1v9ZlhtdEQHsPOMPucqcU3E7YFECY7TaF7TIRJWBboaX1zGMI8DZu0qD fvDFX21f+AuviIN10zxnh5BR4RwFwJHX87uk/UC+XjDiYztLA8Vw9GsAHKXMuNUlhiHhcOIPjn2 /nssUhjkb/mOkFjjs1VPgAvksy6TXwINmeec3X+tMmgLD6mhPc+C+BEesPKreFU2wujNSfH+pvi cy6++GyP8Mq89ylHT1tpWiuWx7OcgqrbMVXM1rW9B/4ps1Q3y63j2sCDcB+dtgLxo/1LigUxdvk iUVvLwNR/5WUJpaQtQNLTXfF1YxRJ5ZefIIbDHEd/y3iOGm+iRWNX6M0VMssnGLqhQAPFB9nxdz T2WP4d8aFx+SFzHZVZ1Ehe/TyimQ2inL6Xwst/yel/f4uxM1k9k2GWurubopW7JV4cYzkEqBAPm O7rZTu+DFauoJhsu5Ow== X-Proofpoint-GUID: Y1yDetNcfr3Gg7pP3U8jRIytjo97cbE0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2026-01-04_05,2025-12-31_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 bulkscore=0 suspectscore=0 priorityscore=1501 adultscore=0 lowpriorityscore=0 impostorscore=0 phishscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2512120000 definitions=main-2601040151 On 12/31/25 2:21 PM, Yu Kuai wrote: > wbt_init() can be called from sysfs attribute and > wbt_init_enable_default(), however queue_wb_lat_store() can freeze queue > first, and then wbt_init() will hold rq_qos_mutex. > > Fix this problem by converting to use new helper rq_qos_add_frozen() in > wbt_init(), and freeze queue before calling wbt_init() from > wbt_init_enable_default(). > > Fixes: a13bd91be223 ("block/rq_qos: protect rq_qos apis with a new lock") > Signed-off-by: Yu Kuai Looks good to me: Reviewed-by: Nilay Shroff