From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C04B3CB54D for ; Thu, 3 Sep 2026 19:00:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788462056; cv=none; b=oFaMpYIhacDXVzjb5n8+T+v95pwNRh0cvS/2/0H2DvBd7irOgD0LmHy/Ii1DaB8FAShBYdDsXtx8GZ5GuXNyPyFXKQ+pIJuwbgu3OMJ+nPQF3Bw4m7bydPmTD+pS64MAFdYKi3+DfXxtY18qvF6sRIqLV5Dj/i8gtFrAnQBgNQ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788462056; c=relaxed/simple; bh=+UzAMDt9on0h4lHLhZr+KtNI1s6q4CzZfQOSs/zHGt8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YsHwGIIX9BGHz4jgRH6/Dy7Gtn3g5ER0pOGqoMoPYQspV6iz3dt9MqrWyezwgEcUeOeH2pvSwbFjMWjSR5NS0O8VuSOovAgmv6thOmSzMmtSL4vN8A/6USexPjd2ACiFN/Q+1sbtM9Zb0zuOTXe4hmxZ6j7BsEFqxjiZGyYk1KE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FEmKSM/Z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FEmKSM/Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A63B1F00A3F; Thu, 3 Sep 2026 19:00:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788462026; bh=77zLKgCat7VRA2FUKJUXA6HIWCC8tb7xY7F3ncSX6FA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FEmKSM/ZZsjZNZwn2P7sUE/ANdSaZaGnA1evbu297Qwi5vj1Hcx3SOqs8dwRmHX7+ xSbaJ35iFfVTG7cp5DepL5sMJWRO1IbpXqDhoWF4LtiUu1BZL8IPAEz16DJ8ddDX8I IPYhK2msXKbJbU2FhdZexFhKCZjYO08pZDZapy5ce7NMWXU1/BdAT7Z7Lm8VQbVcvR xeGfvG9nf3gVo8LdS60lKQ8OhphjM5ihVpCywxBzgLt1OU8oPl7lk1V4jHkgNbfNrb oJ6R7ZBigindUtSDR4vwZH9m2Jv60diUrpxXgNx2/2gWFdwvmYGXqwc2ZrsseiApO5 hceJIR7vOaTqg== From: Sasha Levin To: stable@vger.kernel.org Cc: Dev Jain , Muchun Song , "David Hildenbrand (Arm)" , Alistair Popple , Andi Kleen , Anshuman Khandual , Byungchul Park , Catalin Marinas , Dave Hansen , Gregory Price , Harry Yoo , "Huang, Ying" , Jann Horn , Josh Poimboeuf , Joshua Hahn , Kiryl Shutsemau , Lance Yang , "Liam R. Howlett" , Lorenzo Stoakes , Matthew Brost , Mel Gorman , Naoya Horiguchi , Oscar Salvador , Pedro Falcato , Rakie Kim , Ralph Campbell , Rik van Riel , Ryan Roberts , Vlastimil Babka , Will Deacon , Zi Yan , Andrew Morton , Sasha Levin Subject: [PATCH 6.6.y 2/2] mm/migrate: use huge_ptep_get() in remove_migration_pte() Date: Thu, 3 Sep 2026 15:00:19 -0400 Message-ID: <20260903190019.1523110-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260903190019.1523110-1-sashal@kernel.org> References: <2026090332-posh-plaster-8398@gregkh> <20260903190019.1523110-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Dev Jain [ Upstream commit ac1ec50d71b953524100ddc09057ee61a3dfaff3 ] remove_migration_pte() converts migration entries back to present PTEs after folio migration completes. For hugetlb folios, page_vma_mapped_walk() returns the pte pointer to the hugetlb folio in pvmw.pte, but the code reads it with ptep_get(). On arches which provide their own huge_ptep_get() to dereference a huge pte pointer, accessing via ptep_get() would cause pte_pfn(), pte_present() etc to misbehave. It is not clear whether this has a trivially visible effect to userspace. Use huge_ptep_get() to dereference a huge pte pointer. Link: https://lore.kernel.org/20260703114202.365553-5-dev.jain@arm.com Fixes: 290408d4a250 ("hugetlb: hugepage migration core") Signed-off-by: Dev Jain Acked-by: Muchun Song Acked-by: David Hildenbrand (Arm) Cc: Alistair Popple Cc: Andi Kleen Cc: Anshuman Khandual Cc: Byungchul Park Cc: Catalin Marinas Cc: Dave Hansen Cc: Gregory Price Cc: Harry Yoo Cc: "Huang, Ying" Cc: Jann Horn Cc: Josh Poimboeuf Cc: Joshua Hahn Cc: Jun'ichi "Nick" Nomura Cc: Kiryl Shutsemau Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Brost Cc: Mel Gorman Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Pedro Falcato Cc: Rakie Kim Cc: Ralph Campbell Cc: Rik van Riel Cc: Ryan Roberts Cc: Vlastimil Babka Cc: Will Deacon Cc: Zi Yan Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- mm/migrate.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index 64f6ee8b7fbde..afa21182a7ab7 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -221,7 +221,11 @@ static bool remove_migration_pte(struct folio *folio, continue; } #endif - old_pte = ptep_get(pvmw.pte); + if (folio_test_hugetlb(folio)) + old_pte = huge_ptep_get(vma->vm_mm, pvmw.address, + pvmw.pte); + else + old_pte = ptep_get(pvmw.pte); if (rmap_walk_arg->map_unused_to_zeropage && try_to_map_unused_to_zeropage(&pvmw, folio, old_pte, idx)) continue; -- 2.53.0