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 2847F4AA401 for ; Thu, 3 Sep 2026 12:46:55 +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=1788439617; cv=none; b=ZspbkrmfgGRvR4ab3DsEnyrlAS6EZ9WeCDerLacY8U5WMk1qirlcASBCd4MGsTogdV3Gt9XDB6O89UmxlN/9Fofu4cV7li09bZW91eNBs3tonzEGRJJFifhN/CRkURmjPRvPr02QBzR0sfDU63xfcxbLy60ZEOKpaQqP2u8G/hg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788439617; c=relaxed/simple; bh=fzAkp73paOnkvevsD49DswAL3zi5DrOVOW/j4RMZMXs=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=sY8vEcdJJqXn49/PGjq6DnapOytPWH6KW1QrsF+jGlQo4WmR6NqU2S7HpccGGzkZeoGrBve06LYFq4FkXAPGwMSlwfYloVI4FGekz8MI/vBXaxFUwooBH7Cs73GvN4PqCb4wMPxsQLh84nI9SVsBdP/kYNzpYXR4GyyD8IRL3yY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=w/+VYir7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="w/+VYir7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 525C71F000E9; Thu, 3 Sep 2026 12:46:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788439615; bh=AAGrloPGhEu2wcXlDDTY4HouvX8+HUv0Y5nvCBrugYw=; h=Subject:To:Cc:From:Date; b=w/+VYir7iEoGwcjVuKE49D9ErMl/t7no4Tqg9Q6faefCZtKkHih5ef50Bi2W+eIUd 6kBokLQiGHYSnT9G6E/DMyDuO+9o+xlXtXD4TvFCM7nEVuSXl+in6Hq27+GgEjf8oA o2b7lJdXmEMPJGzUo2H/XrzXeCTkCt1MVmrQ7ABg= Subject: FAILED: patch "[PATCH] mm/rmap: use huge_ptep_get() in try_to_migrate_one()" failed to apply to 5.15-stable tree To: dev.jain@arm.com,ak@linux.intel.com,akpm@linux-foundation.org,anshuman.khandual@arm.com,apopple@nvidia.com,byungchul@sk.com,catalin.marinas@arm.com,dave.hansen@intel.com,david@kernel.org,gourry@gourry.net,harry@kernel.org,j-nomura@ce.jp.nec.com,jannh@google.com,joshua.hahnjy@gmail.com,jpoimboe@kernel.org,kas@kernel.org,lance.yang@linux.dev,liam@infradead.org,ljs@kernel.org,matthew.brost@intel.com,mel@csn.ul.ie,muchun.song@linux.dev,nao.horiguchi@gmail.com,osalvador@suse.de,pfalcato@suse.de,rakie.kim@sk.com,rcampbell@nvidia.com,riel@surriel.com,ryan.roberts@arm.com,stable@vger.kernel.org,vbabka@kernel.org,will@kernel.org,ying.huang@linux.alibaba.com,ziy@nvidia.com Cc: From: Date: Thu, 03 Sep 2026 12:50:00 +0200 Message-ID: <2026090300-awry-struggle-b110@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 9be12ffa78cd087d41086f937a156435d4e588e9 # git commit -s git send-email --to '' --in-reply-to '2026090300-awry-struggle-b110@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 9be12ffa78cd087d41086f937a156435d4e588e9 Mon Sep 17 00:00:00 2001 From: Dev Jain Date: Fri, 3 Jul 2026 11:41:56 +0000 Subject: [PATCH] mm/rmap: use huge_ptep_get() in try_to_migrate_one() try_to_migrate_one() is used by folio migration to replace a present mapping with a migration entry. For hugetlb folios, page_vma_mapped_walk() returns the pte pointer to the hugetlb folio in pvmw.pte, but the code reads the huge pte entry 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. Commit a98a2f0c8ce1 copied the bug from try_to_unmap_one into try_to_migrate_one. [akpm@linux-foundation.org: coding-style cleanups] Link: https://lore.kernel.org/20260703114202.365553-4-dev.jain@arm.com Fixes: a98a2f0c8ce1 ("mm/rmap: split migration into its own function") 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 diff --git a/mm/rmap.c b/mm/rmap.c index e0d7b33ceee4..9939400e77c7 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2500,14 +2500,18 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, /* Unexpected PMD-mapped THP? */ VM_BUG_ON_FOLIO(!pvmw.pte, folio); - /* - * Handle PFN swap PTEs, such as device-exclusive ones, that - * actually map pages. - */ - pteval = ptep_get(pvmw.pte); + address = pvmw.address; + if (folio_test_hugetlb(folio)) + pteval = huge_ptep_get(mm, address, pvmw.pte); + else + pteval = ptep_get(pvmw.pte); if (likely(pte_present(pteval))) { pfn = pte_pfn(pteval); } else { + /* + * Handle PFN swap PTEs, such as device-exclusive ones, + * that actually map pages. + */ const softleaf_t entry = softleaf_from_pte(pteval); pfn = softleaf_to_pfn(entry); @@ -2515,7 +2519,6 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, } subpage = folio_page(folio, pfn - folio_pfn(folio)); - address = pvmw.address; anon_exclusive = folio_test_anon(folio) && PageAnonExclusive(subpage);