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 CAAA73876B3; Fri, 4 Sep 2026 05:07:24 +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=1788498447; cv=none; b=PEYvg9S+8lFbhzMVQGvL6tfddBQSi6bXKCK6YYlQLdt2f17Pmqw8xmcZHrB93J1FBSoeB1tc2MPhqd1OUOtaVLE5rEeSVb4tfQBnamyxENgCzSbk4azocdxIb6WYytqGWVftLQk+c6GGU2DTcOy8OrHfsbulYXBWo3A5IUzrQPs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788498447; c=relaxed/simple; bh=ZjE06zKzGtlFYe5hMdYp4ZpTk11T75wbL23+6Cfy1LM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HEeNalgYDj9FVdbMRkE91GZGJ59I1wJlrgQ68WIB9x/3vIWiQVBcx+kmBNwYntJOy6S9OcpnikzsrUGaR2YOrgWfnrQ3CFGvnGHZN5MD4UPEwYZx361lOgZvfoyyo7QyZ3Qtkk/8fyjlGTtBFpuhLYFQeWc/Ok37GXulZMrOEgE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sSrwxrgh; 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="sSrwxrgh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C50B1F00A3D; Fri, 4 Sep 2026 05:07:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788498444; bh=OxK+8sCo/121dy7eG6dM8MfnDK438sor41q5iB7R+04=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sSrwxrghTAjBEnQPNCV2f+sYKPxgHgsXFdQY9rBAnYdWz/DbxuB+UnSqUP+wDHte7 Rqbo1Mgwi3cVuzPBa1v2geAIjVIzeT1hsSoNfROe3rdg6U5ahJv3dJXrlnHSGbou+P LbZg8DqlpgYxPYIZlnP3KFoedJahHFZemJyvdZb0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, 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 , =?UTF-8?q?Junichi=20 Nick =20Nomura?= , 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 Subject: [PATCH 7.2 064/713] mm/rmap: use huge_ptep_get() in try_to_unmap_one() Date: Fri, 4 Sep 2026 06:50:32 +0200 Message-ID: <20260904045805.274508298@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dev Jain commit f5407e9b697c940e78b27ff63c6e14d8d171adc3 upstream. 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: Greg Kroah-Hartman --- include/linux/hugetlb.h | 2 ++ mm/rmap.c | 16 ++++++++++------ 2 files changed, 12 insertions(+), 6 deletions(-) --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -1262,6 +1262,8 @@ static inline void hugetlb_count_sub(lon { } +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) { --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2095,14 +2095,19 @@ static bool try_to_unmap_one(struct foli /* 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 foli } subpage = folio_page(folio, pfn - folio_pfn(folio)); - address = pvmw.address; anon_exclusive = folio_test_anon(folio) && PageAnonExclusive(subpage);