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Wed, 28 Jan 2026 10:41:53 +0800 (CST) Received: from dggemv706-chm.china.huawei.com (unknown [10.3.19.33]) by mail.maildlp.com (Postfix) with ESMTPS id 956094056D; Wed, 28 Jan 2026 10:45:21 +0800 (CST) Received: from kwepemq500010.china.huawei.com (7.202.194.235) by dggemv706-chm.china.huawei.com (10.3.19.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 28 Jan 2026 10:45:21 +0800 Received: from [10.173.125.37] (10.173.125.37) by kwepemq500010.china.huawei.com (7.202.194.235) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 28 Jan 2026 10:45:20 +0800 Subject: Re: [PATCH] mm/page_alloc: Fix freeing of failed-split poisoned compound pages To: Jiaqi Yan , Boudewijn van der Heide , CC: , , , , , , , , , References: <20260116141157.29578-1-boudewijn@delta-utec.com> From: Miaohe Lin Message-ID: <3ec3f4de-2c38-5ec4-4b4a-d7a801efe558@huawei.com> Date: Wed, 28 Jan 2026 10:45:20 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.173.125.37] X-ClientProxiedBy: kwepems500001.china.huawei.com (7.221.188.70) To kwepemq500010.china.huawei.com (7.202.194.235) X-Rspam-User: X-Rspamd-Queue-Id: 8CDB4100006 X-Rspamd-Server: rspam07 X-Stat-Signature: ci7thtez5prpfsoynoiejbfekne7ezom X-HE-Tag: 1769568326-634856 X-HE-Meta: U2FsdGVkX18u9p3diJ+kyoMsgoA56NL7okeaB3GoNtIk7S8aXGvxdmRSzV+tVQHwyus3XZMTJEmKR7cXNeO9/zN3oDWLJLjtpQ1q7Mner4MSVAxih25q8K7z3dJDNXZWBxgBRIzPEyqsK3pvlsPjZZkhqMePG0ZHKnTaoLkB13kSnccQKl5SBerYpiOBH+ZCQynbWZu0BLYLIUYADBdF8PHoiRQwA1aRnhlqQxSnTzW2XQrlQsz1xFdotAf++QFzT2yPi3UcDTHRcEag2iVuykkNh2DrEaT8SgeTnQNf1SDN6jGViSiKhzxlghrfoktuPhcgi8sXtbWE6IlO7QBo3a/d2ABdBuLx4GjuL+N/HOhv0hgQmW/RR8yvvwAWL/RJbhIi+92ODGkf0Xzff0bIimLAd0SIORwaKF4YGxD/yV/fZtTQxCrLSgpo3LdkmJacglBuzIjLUVYePV1t8vnw625uSKx9Q5cmDpbK98PuMGEVidi0CIywI42/A54GtVxWCyL3nDf0FTIreEbuP72ArGhHwrgdN82aoDUhQlV7KhR8DoEAUaRWjUgVEbUEVLvVfqPQPbDSngxEbzObPlnGL/HqNQy/0/Mpp5r/bWa46iuFsFddqJutCma7Z/tXqUQRIKgKc36UBOYrqFPoDbcpH+YD4wWpgUlbaUSoHs8dj5a5sZNM3wyQ+lL1m64J9s/mgGShr8VowX3rQtkXDoGr+hJrXn7pKnk5n27CkPzcgmekVdjGO7BxCUiJZJ++C73Ggy/0sUszqTh6NQDfzFCT0/tz3g2ZbaJ0XRAiFQd5X9hKBHAVIl7Zb4IDIODXsvIu2ddBoxkWWGt7pCxzVzyZt6536o5qvHNwj7dEQyLs20RXWyYs+Ip6u83Or/adr8Ttj+rHw2o+KSPhYsrkecrdFT2rWV0Wln8T5zUjLM0FFBzRiFbHal1goh4pRnV/6eyyffM8IixGWMnvCfSH2PB qI1Jszcj cpSAzlE+g6McwXyg7RHcbGIm+U/NQGyvkdUAOHwsBjpTE7V10jxrMN49LRaocHievi/Vt1S7WNHgPg5OjKk3gJEWND3x+0255/ha4A8DYLyVVKfpCI3BbdSks0Uz/bYGDAJv/s0gNS9jKkeIj3ETyDNsUxie20TWHkINX2PUN374iDu5Okr2WaWcFvBq0ocvNMA9dhIjewffWQmlUxq4cS06x25pZQqSyei3DW0Q0F6bNjRtKSXtxLT8AHBY/YveaDXQqXK1ip/KiQENi874eR8SIj0Bmkwvzael2LnECoCCD/WrIda220vAQFI2w6xq7S4Xawi5RXVBtM8eJGZ2x60AZg1RNjVJYLff+YAdnXM48qOdS9QVzRHH71Zgk51N73xlqSVDQlLVu2gIBiOYjnwiwgBbkORZ3aURLJdYfVJVPsRibmdi1X87jweshUOHlx55hNH5NJ/BhUDG+r10J/2Oo2NWpeXCVbLLE X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/1/24 12:42, Jiaqi Yan wrote: > On Fri, Jan 16, 2026 at 6:12 AM Boudewijn van der Heide > wrote: >> >> Thanks Jiaqi for the feedback, that is very helpful. >> (and thanks Miaohe for connecting the issues.) >> >> After going through the memory_failure(), >> I can see it indeed puts the PG_HWPoison flag on the specific subpage pointer, >> and therefore my fix won't work as-is. >> >>>> >>>> Yes, this is also a problematic scenario for Hugetlb HugePage. And Jiaqi works on >>>> it now [1]. I think Jiaqi's patches might apply to THP scenario too. Add @Jiaqi to >>>> verify this. >>> >>> Yep, I think my work will also help solve the concern when >>> try_to_split_thp_page() fails. >> >> Your fix makes a lot of sense for hugetlb, >> as it linearly scans through all the pages. >> From my understanding, >> your fix also provides the perfect architecture for also checking THP, >> though it doesn't yet cover the in-use THP case outlined. > > Oh, sorry I went ahead myself and assumed the split-failed folio would > eventually be released to the buddy allocator at some point when > userspace processes who owns/maps this THP are killed or exited. > > Zi and Miaohe, am I right about this? or do we need explicitly handle > in-use and split-failed THP? IMHO, it's enough to handle poisoned sub-pages when in-use or split-failed THP eventually be released to the buddy. Thanks. .