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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1777457504; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hQnZQYLrTlNYy1jc1rXnnTon8LpqLdCTjRpZns17oGo=; b=xEM+oNRWB3iEUl7EvR41PZcCxwM+tlM71BYBVb0m6mTHUTUlRsZy9GVgnWzfYDsO7wLdvx qqqBFWU0yQ8IgsOppvyiVpGtZRPXqj5d1PS22xkgYBQtdQrPjdRNGC6Ec9FZq1PHvHQCTe D5/aom5/W69PK8yAlF8NAp+unM5fxYc= From: Usama Arif To: Muchun Song Cc: Usama Arif , Oscar Salvador , Miaohe Lin , Muchun Song , Vishal Verma , Ying Huang , Dan Williams , Naoya Horiguchi , linux-mm@kvack.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, David Hildenbrand , Greg Kroah-Hartman , Rafael J Wysocki , Danilo Krummrich , Andrew Morton Subject: Re: [PATCH v2 3/3] drivers/base/memory: fix locking for poison accounting lookup Date: Wed, 29 Apr 2026 03:11:33 -0700 Message-ID: <20260429101134.1358607-1-usama.arif@linux.dev> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-HE-Meta: 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 2j8orTUn URi4jmBhLrFCjgtK/+6J2joEF8iHes9vNCtQHSmfGjfuVhPMQaKbQV1fPhO8ifjkCJtz/uhjIFkw4pu5ndwHIpa/jEUqaf/qIK1FokYcPu4hvsjOq2Lal0S9lRxwhnM7qZMiJwv/dRLzNKip9/75diPbZHAMPa34tlAYzo1mnOfxRr2lMGbK8+y6KumI0t/D5mxu4RTR00i8DbDlL6n+7G4qon+b9IRt720IuBqD9x3Qa0j6ejF9Dr1ubCeFxrKnj5S4/36S6J+Rh6O1cB0aFMB/BOq89CSH5F4DrZKPazNW823EVtBqb6chRtOHkWcJ/m9P3j6X7RY1br6utGZiwGv56z1gNYqAk9WLq X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 69EAF1A0004 X-Stat-Signature: ma97fnr6guby9hdtbk6zmidfay4b63zc X-Rspam-User: X-HE-Tag-Orig: 1777457508-338704 X-HE-Tag: 1777458154-457503 X-HE-Meta: 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 DCm6r0ug muYpbxBpZJjmHYeYZa5EQlXg7IKzv+bWbJngs/+vs3se1AU6m4oYQnoQibEd+y0P8O5aJZrR0nZCGOk2fa6nDKA3757BsjL7VjDp2p4mZ2hii/v9F+zO7D3Fubn1UrX1NplS4MUaRtlTnxIeGp3sboAUBgkz/iXnveFsrEnfZpp79gpNosvMNLXKnWFV+NAWH/chPYZxNamJmqXv08FQWdkk7Ov2Wjxtw2P6sOJSSn+qdEo6qcUaPxmzWv4eoeeqPSOH/lBEGLS8/8VIoPlj3rTXnz4Rxo22GPI+w7374SmdgccyawXE/cvKE7JnGwEZ0mmfO9BSVzBrf4kA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, 29 Apr 2026 12:18:08 +0800 Muchun Song wrote: > > > > On Apr 29, 2026, at 11:32, Oscar Salvador wrote: > > > > On Wed, Apr 29, 2026 at 11:08:51AM +0800, Miaohe Lin wrote: > >> Right, I missed that. Thanks. But I'm still worried that there might be potential issues. > >> For example, this function could be called while lock_page is held. Acquiring lock_device_hotplug > >> while already holding lock_page might cause problems, though I haven't seen any specific issues yet. > >> Also there might be some other potential scenarios that haven't been considered. Hope I'm just > >> overthinking it. :) > > > > lock_device_hotplug is a mutex lock, and we already take other mutex locks while > > holding lock_folio in other paths, so I am not sure I see what should be special > > in this case. > > Hi Oscar and Miaohe, > > I saw sashiko's report [1] related to folio lock and lock_device_hotplug. > Seems it is possible. You can correct me if I am wrong. > > [1] https://sashiko.dev/#/patchset/20260428085219.1316047-1-songmuchun%40bytedance.com > > We could fix this by calling action_result() without holding folio lock. > What do you think? > Hello Muchun, You could end up in memblk_nr_poison_sub() while holding hugetlb_lock spin lock from get_huge_page_for_hwpoison(), right? Lockdep would flag this as sleeping while atomic when acquiring mutex I think.