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Thu, 18 Dec 2025 14:20:04 +0000 (GMT) Message-ID: Date: Thu, 18 Dec 2025 19:50:03 +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 v5 02/13] blk-wbt: fix possible deadlock to nest pcpu_alloc_mutex under q_usage_counter To: Yu Kuai , axboe@kernel.dk, linux-block@vger.kernel.org, tj@kernel.org, ming.lei@redhat.com References: <20251214101409.1723751-1-yukuai@fnnas.com> <20251214101409.1723751-3-yukuai@fnnas.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20251214101409.1723751-3-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=V/JwEOni c=1 sm=1 tr=0 ts=69440d99 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=wP3pNCr1ah4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=tJLSzyRPAAAA:8 a=VnNF1IyMAAAA:8 a=NL1F5aIbUArUtQSLZB8A:9 a=QEXdDO2ut3YA:10 a=H0xsmVfZzgdqH4_HIfU3:22 X-Proofpoint-GUID: 8sC0XLhsqr_Z2YRGVR4ZBop1fgGu2MW6 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjEzMDAyMyBTYWx0ZWRfX1dvt1rYvFJ7g GA1gYhGMoZ4+p17oRONlQpaKzaIM+RPRH0b5uX5Nz+Q5vFy93odSelUuPfhT3C4Yr1hJa+UajDq yP1k0a5YJ+x38J+PRGdRmsRPe5wqtjTrf8/yb+Oh+zTAdmXbvG59sfBY5bArf2Tr73D4tPTUHGq DLWC1kDDvHtz6usjRipephsnHPnj9lHjnjKB/6QaY2EUoa7bdGemHvrDI8bhQQFpYDjkEnIDjG+ /nIj0d5k9Rn2ySH8tgKEVFwuH41ii3WglylBEKM1/zrI5vR1LGSVdmmXZTivqSjlZP7JzV9rwjG uE9jNx1EFDpyIK8KYrPBmWyn3+h7srqPXYK7MUcC/bWUKoZZi8wxPZVNiiBacIZezUXJyx3iS60 gf9zmJ67+R3t9zWLdwyNmbWZe1z46Q== X-Proofpoint-ORIG-GUID: 8sC0XLhsqr_Z2YRGVR4ZBop1fgGu2MW6 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=2025-12-18_02,2025-12-17_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 suspectscore=0 priorityscore=1501 malwarescore=0 clxscore=1015 bulkscore=0 spamscore=0 lowpriorityscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2512130023 On 12/14/25 3:43 PM, Yu Kuai wrote: > If wbt is disabled by default and user configures wbt by sysfs, queue > will be frozen first and then pcpu_alloc_mutex will be held in > blk_stat_alloc_callback(). > > Fix this problem by allocating memory first before queue frozen. > > Signed-off-by: Yu Kuai Looks good to me: Reviewed-by: Nilay Shroff