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 0B47C46EF79 for ; Fri, 4 Sep 2026 11:25:34 +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=1788521136; cv=none; b=rObS+bhDgciy0UqnLhuxW3YjEe7XFsGop6bKiU3rONXHpx8aXp6Bfda8z92e8olEnpr7lggsjOYbZRWuTCNL5+FL3GMaS3ObQnc+D6JBMeNUmjqLqJd0JJk4478ee86YhGN1Gtt35NZOZ8erNExKB9TeGN0OsKDl1OisPX921X4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788521136; c=relaxed/simple; bh=3zg+m78oCq8FoH2C82UwCzwEn3UK9Vr3p+x83043AL8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Zf0W3URwwHy2krT0TKfK1vgKb0g6rpoBmO+j8ipQf+N3f/rX+96yFsF8b9tM4G2wfurrSmTpMAKgWH9hEo8d58DuwLxoR6i0sZX0p1eFa0Tc9OzZ3KLS/mNoclKmUST5jDPOiRDWUJbK1Pt9WvX86o/1M9L1gx3ryVPgRlqc9Sc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kd79Fxta; 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="kd79Fxta" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B80111F00A3D; Fri, 4 Sep 2026 11:25:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788521133; bh=DZcVpMP5HDdYhlgu1ccm04lVVHYWmo0zsg7abG483AI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kd79FxtaVQ1PBKwG37ufIvIRkeNC4zEdJaxACGHH/fO56TW8qH3XcYUDOeCsJoPZd hQ7PMSZsdWwZ2CvnOUYondB8hLXu9DqJJ36cqVbj3be2vGkUXvCiv9oyXK8LQg0rz5 PjbISAAv1F9t1biNtMdAKN/bbymAZf070uxxV6SRAonN0fdo1AdrJu0F96EZwopHwp FgncJo6ghOUNUnHjV9PFtD+eAbtd+zjsmDO673YjhntR0wQUZoDs9AoA8Ia6NfLj82 1EHmK81qqSvHFn1J3tIlTdqwQ/jd3/aQP9EmZVtP+XruzBptPGyaAgSTWb5qjChB27 099FTDHsUuXcQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Dev Jain , David Hildenbrand , Muchun Song , 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 6.1.y] mm/rmap: use huge_ptep_get() in try_to_unmap_one() Date: Fri, 4 Sep 2026 07:25:29 -0400 Message-ID: <20260904112529.3415033-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090346-evaluator-pointless-7f22@gregkh> References: <2026090346-evaluator-pointless-7f22@gregkh> 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 f5407e9b697c940e78b27ff63c6e14d8d171adc3 ] 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 Signed-off-by: Sasha Levin --- include/linux/hugetlb.h | 2 ++ mm/rmap.c | 7 ++++++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 6b78a0f457d95..aa089e58bc41f 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -1199,6 +1199,8 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm) { } +pte_t huge_ptep_get(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 886000da89a6f..4c8afa9ffb7ba 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1527,8 +1527,13 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, break; } + if (folio_test_hugetlb(folio)) + pteval = huge_ptep_get(pvmw.pte); + else + pteval = ptep_get(pvmw.pte); + subpage = folio_page(folio, - pte_pfn(*pvmw.pte) - folio_pfn(folio)); + pte_pfn(pteval) - folio_pfn(folio)); address = pvmw.address; anon_exclusive = folio_test_anon(folio) && PageAnonExclusive(subpage); -- 2.53.0