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Mon, 3 Aug 2026 06:51:24 +0000 (GMT) Message-ID: <431ed2f9-9fde-4ff7-9db7-51a56bec17c0@linux.ibm.com> Date: Mon, 3 Aug 2026 12:21:23 +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 0/4] blk-cgroup: fix blkg list and policy data races To: Yu Kuai , tj@kernel.org, axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, zhengqixing@huawei.com, hch@lst.de, yizhou.tang@shopee.com, yukuai@fygo.io References: <20260802112525.3933753-1-yukuai@kernel.org> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20260802112525.3933753-1-yukuai@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwODAzMDA1OCBTYWx0ZWRfX9MHQGnu/s4Cl feHILuCk4a9d61q8JmfX8UZm7xT/2iBXeOyI7M8TJ7oqf38EA9to/WbADbtmsEFtJOtN4mlnvNA QPrrcdGM6K1bfG8s3nMNNG7tkdsoGAI= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODAzMDA1OCBTYWx0ZWRfXwJH1TJPrgzhe AtbIKo8sVOo4RzleYBy/PdaDhsqfgjjsewtf+YXDSdt28Plk4/8Hskxx4CIjogl+wbgrASf2C0j HwoJ1dpHl3LBoEaL/jlDljWvyXfjXQKZTz9ztGTJVpAzZTJsDa6LkZJa3dzMQ0vvyanbgPNR1Km 0cL3y/FQXE76cKFeZTrihJDIA+Qc8Pen+xzVelEMFPxtlMMCJomsD0uorI+VIz4QtvPIjZQyQKn ZJdnWj5FIQMA5114iGwoWqIwQ78b88jrSkuntN8nVrDQML/A7b3nEJ2DzDzkSwch0e2i4Hhhxny EIATasrfw0S0m9asWKY86Lo1Oe7pE+EfdFxaawMhbDTnEoRTEB11kEwuQ3tawlDfw+Siy8EMxvb jN0nUPqkb0lWWGFrMOf/pV1Z86rImzWd2cU6EmfJeMbHufb1TrCqv5h6DQuRhh6pNpe68cXjO3l 7GShgTLd+Q/fX9Ss9pA== X-Authority-Analysis: v=2.4 cv=SI1ykuvH c=1 sm=1 tr=0 ts=6a703a72 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=OXP71DqVsUOFssmpANUA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: CAJPe-0nk7ZcBOl9jkiVMryB_qLI2SHO X-Proofpoint-GUID: CAJPe-0nk7ZcBOl9jkiVMryB_qLI2SHO 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=2026-08-02_06,2026-07-30_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 bulkscore=0 suspectscore=0 impostorscore=0 spamscore=0 phishscore=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608030058 On 8/2/26 4:55 PM, Yu Kuai wrote: > From: Yu Kuai > > This set fix some problems that are reported long time ago with minimal changes, > the blkcg_mutex refactor I'm working on can fix these problems as well, but it's > complicated and may not land in this merge window. So I think this set should land > in this merge window first. > > Patch 1 protects blkg_destroy_all()'s q->blkg_list walk with > blkcg_mutex. > > Patches 2-3 fix races between blkcg_activate_policy() and concurrent > blkg destruction. > > Patch 4 factors the policy data teardown loop into a helper after the > race fixes. > This series looks good to me, however as I recall, we discussed about protecting blkg_create() as well using ->blkcg_mutex. I remember the blkg_create() is not protected with ->blkcg_mutex under each call path, so would you to also cover that change in this patchset? Thanks, --Nilay