From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793306217; b=5i0oEPFeJ0ercMb5b+EBimYHRfVIMnb0tSGtJUlK/VleTpBG4iWm7Os7CGGCjSJP6T/1 qwDknJwnBVuP6hTR5w0tg89bXJSwlj6u+IwUBPI5dBAMw2M3QKOGNRiAlrbR1iMp0OkXf 0oqKTwNxHIV7/jY/Q8q4Gbl4GFZgk98Bd/nIus0tuGkwZmpgwcbBjw7Xo6b9SeaEjZzpn MtbbV8rL1tQ363bhkxJzkx2yVS61e81tJfgZxiIQsnvMlUn6lSNw7m7GqkoRWZu7dHX8F LSQaXBWTpu+fhQLiyG3J+ppjqczaYmvN3REoxz8/1qD73ZhfAGJqxoi9saOokEnIoAg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793306217; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=39sO4eVWOAhWIFY7dwmw5wDLBZR1O1Wkdyg2pyVIaSw=; b=cybTkaxjpRO/Lt6ygiMagtHK4sFUS/Omqa1a2nvQ2bkfyENzXpGBTXHjXsQKBq4NIyoR UllgkOklJHMQ9oTMPShmX1TCyO6CS+QDtGZjbBREq1QUtaXsND8R/iIFBIzCjGBQqekLl iaXPvw+LOscDIMLP8oBYoOFN4zZbvrkmrOQsIW1c4sxKq6PMhGRvGEmL+5GgNIfsl1IDE BplWblBwBisWYVVbfESYk01+2T+KCW8aN5/GOjhDyDRGQThbcuOI7wfZx5O8zcrnnPN6S akYldFBUg/TcyEohPzezfN3QR7h87e/0zCL7uixmxxoOg23Hp2jhG5H0RjxMwFQB8Bw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="hLIyzFr/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5969C606A335; Thu, 29 Oct 2026 20:36:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=hLIyzFr/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6E0E1F01828; Thu, 29 Oct 2026 20:36:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793306217; bh=39sO4eVWOAhWIFY7dwmw5wDLBZR1O1Wkdyg2pyVIaSw=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=hLIyzFr/V/VvcGfnmQExxQg7IIwVIxjs2CWLB1sCab5pSvGmM4huLIGWjFbTIQt/g LvIjs//slU9Pq4A2SJLgO204tjYJlgMOO2JybMj7kVGc2TG/vohe/X3Zz7FeCoRLRc nrf/oQie/gYaRI5uDKW3ey8ucpkNlAPAQfa6wQ9bTo3VzjDmA6sP4x+IV/OttkAqd3 JyWct3e8oJ1K9D8M52trvZOLS6s+qHpCPGamQ5HJ5Fz9lHdo495ySJkjCRlFWivA2z btGsxZgoULfAhGK6RKAeYV19UJkhbRKtCZuqzEA68xNrUH7XyrReQRSJ+prYoLs7a3 fqpJE+V6bRCdQ== From: "David Hildenbrand (Arm)" Date: Thu, 29 Oct 2026 21:33:09 +0100 Subject: [PATCH v2 14/47] mm/huge_memory: fix zapping migration entries for device-private THPs X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261029-fixes_core-v2-14-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> In-Reply-To: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> To: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, Chris Mason , stable@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1532; i=david@kernel.org; h=from:subject:message-id; bh=I7I0jhaFoDQ+nBqhpxvpT0b9yhPeTYbK2Z2XhTeg/TA=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLIer21bu2tt8uaHDhHRMpPkLUTW16ivZ94sK3hdWn5lQ 8L31aqJHaUsDGIcDLJiiixBwfcNXr5cV1vtxscMM4eVCWQIAxenAEzkghUjw3rfBSFaX+RXSHif D2cU2Dqz50GT77tKx0VZSuXaaz3ahRj+KTklP/0QL6kglxAToL0i5/q5rtPBtyrT2i1fVd2MMHv HAQA= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A From: Chris Mason A PMD migration entry can refer to a device-private folio. zap_huge_pmd_folio() checks the folio type instead of the entry type, so it treats such a migration entry as a device-private entry. Installing the migration entry already removed the reverse mapping and dropped the mapping reference. Zapping it must not repeat those operations. Concurrent MADV_DONTNEED during migration back to system memory can trigger this. Check the PMD entry type using pmd_is_device_private_entry(). Fix generated by an LLM and sent by Chris Mason in private. Fixes: 368076f52ebe ("mm/huge_memory: add device-private THP support to PMD operations") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify description ] Signed-off-by: David Hildenbrand (Arm) --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1d65c4f576f9..c5aa0a0a407c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2493,7 +2493,7 @@ static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) static void zap_huge_pmd_folio(struct mm_struct *mm, struct vm_area_struct *vma, pmd_t pmdval, struct folio *folio, bool is_present) { - const bool is_device_private = folio_is_device_private(folio); + const bool is_device_private = !is_present && pmd_is_device_private_entry(pmdval); if (folio_test_anon(folio)) { add_mm_counter(mm, MM_ANONPAGES, -HPAGE_PMD_NR); -- 2.43.0