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 BB9AD4AA1D2 for ; Thu, 3 Sep 2026 12:46:35 +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=1788439597; cv=none; b=L6CR82rQMYuqaBBFJMtME0PhBQ9EBKtWr+LvFHHnKzwSPW0BKSiOCCgON/jwPDp+AICmLJK/CzUWFP1N2TkckEwDNuTjXDjv8h/pCoaidF5Q3z+zxPKJC1ocFVDyrJd+tIdH+PT1HoUqnnkU6Gd/1P+I329E2EBTLgjPebhmjwI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788439597; c=relaxed/simple; bh=YCjgC3L9lF0Ee5+6EBXDprdAlTTbfZ3/cxjmXOKvd/A=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=jvimNaUBMh6JLLqEG/mA0NtXJCnK0eUEreDxGw8Kj0bBlmdLx/Z/7OZmWZ+TvJfSiEooJXiaJKgh8ebGZMG7gt/fxOZis/6sNplKyA7DLlrVNqdwVXiAMXMWwwxxt/3naU+ulobjIgmYSuEC18wNHpcPdcnpG6PUUI9qNJs2uhg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CGEFqUd5; 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="CGEFqUd5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0F071F000E9; Thu, 3 Sep 2026 12:46:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788439595; bh=YI56GSNyKP1U/B+VkLDgRoZdyaNjb2Nbat6uAmypCrg=; h=Subject:To:Cc:From:Date; b=CGEFqUd53rEB0r9OQGcI8fVdB/kWet/9ifoFP3fFSbiAnrg3lfjm9duZtOz00BQE3 sSGpc5p2G8JgBeGHJCAuHjEO6e05tqDJpL/WBMkq3dBbSQbtZLrV2YRjlFL0TXnmf2 R4yWiG1oiTUg24qTm6Y3TvnI00f//wJqhzvPB0k4= Subject: FAILED: patch "[PATCH] mm/rmap: use huge_ptep_get() in try_to_unmap_one()" failed to apply to 6.6-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 12:49:46 +0200 Message-ID: <2026090346-wildfire-tapered-9281@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 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x f5407e9b697c940e78b27ff63c6e14d8d171adc3 # git commit -s git send-email --to '' --in-reply-to '2026090346-wildfire-tapered-9281@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f5407e9b697c940e78b27ff63c6e14d8d171adc3 Mon Sep 17 00:00:00 2001 From: Dev Jain Date: Fri, 3 Jul 2026 11:41:55 +0000 Subject: [PATCH] mm/rmap: use huge_ptep_get() in try_to_unmap_one() Patch series "Fix incorrect access of hugetlb pte entries", v3. There are various places which use ptep_get() to get the pte entry corresponding to a hugetlb folio. Some arches (like s390) have special handling to compute the pteval, so they provide huge_ptep_get(). Use this helper consistently. Additionally, some code paths may provide huge_ptep_get with an unaligned address. This is a problem on arm64 (I checked other arches and it looks fine for them), which is fixed in patch 1. The fix is made to be backport-friendly: the cleaner fix would be to perhaps pass the hstate to huge_ptep_get() - that is wider churn and we can do that later. This patch (of 5): try_to_unmap_one() handles hugetlb folios when memory failure needs to replace a poisoned hugetlb mapping with a hwpoison entry. In that case 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. Just use huge_ptep_get() for dereferencing a huge pte pointer. Link: https://lore.kernel.org/20260703114202.365553-1-dev.jain@arm.com Link: https://lore.kernel.org/20260703114202.365553-3-dev.jain@arm.com Fixes: c7ab0d2fdc84 ("mm: convert try_to_unmap_one() to use page_vma_mapped_walk()") Signed-off-by: Dev Jain Reported-by: David Hildenbrand Reviewed-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/include/linux/hugetlb.h b/include/linux/hugetlb.h index 817b8b4223fa..95b1b6ee1f96 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -1270,6 +1270,8 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm) { } +pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep); + static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { diff --git a/mm/rmap.c b/mm/rmap.c index 408e542649b5..e0d7b33ceee4 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2095,14 +2095,19 @@ static bool try_to_unmap_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); @@ -2110,7 +2115,6 @@ static bool try_to_unmap_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);