+ mm-memory_failure-reject-unsupported-non-folio-compound-page.patch added to mm-hotfixes-unstable branch

+ mm-memory_failure-reject-unsupported-non-folio-compound-page.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

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The patch titled
     Subject: mm/memory_failure: reject unsupported non-folio compound page
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-memory_failure-reject-unsupported-non-folio-compound-page.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory_failure-reject-unsupported-non-folio-compound-page.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/memory_failure: reject unsupported non-folio compound page
Date: Wed, 4 Feb 2026 19:56:03 -0500

When !CONFIG_TRANSPARENT_HUGEPAGE, a non-folio compound page can appear in
a userspace mapping via either vm_insert_*() functions or
vm_operatios_struct->fault().  They are not folios, thus should not be
considered for folio operations like split.  Change memory_failure() and
soft_offline_page() to reject these non-folio compound pages as
EOPNOTSUPP.

Add PageNonFolioCompound() helper function.  This function is functionally
equivalent to folio_test_large() && !folio_test_large_rmappable(), but it
is supposed to be used on struct page.  So open code it instead.

Link: https://lkml.kernel.org/r/20260205005603.274383-1-ziy@nvidia.com
Fixes: 689b8986776c ("mm/memory-failure: improve large block size folio handling")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: 是参差 <shicenci@gmail.com>
Closes: https://lore.kernel.org/all/PS1PPF7E1D7501F1E4F4441E7ECD056DEADAB98A@PS1PPF7E1D7501F.apcprd02.prod.outlook.com/
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/page-flags.h |   16 ++++++++++++++++
 mm/memory-failure.c        |    9 ++++++---
 2 files changed, 22 insertions(+), 3 deletions(-)

--- a/include/linux/page-flags.h~mm-memory_failure-reject-unsupported-non-folio-compound-page
+++ a/include/linux/page-flags.h
@@ -1102,6 +1102,22 @@ static inline bool folio_contain_hwpoiso
 
 bool is_free_buddy_page(const struct page *page);
 
+static inline bool PageNonFolioCompound(const struct page *page)
+{
+	if (PageCompound(page)) {
+		const struct page *head = compound_head(page);
+
+		/*
+		 * Without CONFIG_TRANSPARENT_HUGEPAGE, PG_large_rmappable
+		 * should not be set/used.
+		 */
+		return !IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) ||
+		       !test_bit(PG_large_rmappable, &head[1].flags.f);
+	}
+
+	return false;
+}
+
 #ifdef CONFIG_MIGRATION
 /*
  * This page is migratable through movable_ops (for selected typed pages
--- a/mm/memory-failure.c~mm-memory_failure-reject-unsupported-non-folio-compound-page
+++ a/mm/memory-failure.c
@@ -2440,9 +2440,12 @@ try_again:
 
 	folio = page_folio(p);
 
-	/* filter pages that are protected from hwpoison test by users */
+	/*
+	 * filter pages that are protected from hwpoison test by users or
+	 * unsupported non folio compound ones
+	 */
 	folio_lock(folio);
-	if (hwpoison_filter(p)) {
+	if (hwpoison_filter(p) || PageNonFolioCompound(p)) {
 		ClearPageHWPoison(p);
 		folio_unlock(folio);
 		folio_put(folio);
@@ -2945,7 +2948,7 @@ retry:
 	ret = get_hwpoison_page(page, flags | MF_SOFT_OFFLINE);
 	put_online_mems();
 
-	if (hwpoison_filter(page)) {
+	if (hwpoison_filter(page) || PageNonFolioCompound(page)) {
 		if (ret > 0)
 			put_page(page);
 
_

Patches currently in -mm which might be from ziy@nvidia.com are

mm-memory_failure-reject-unsupported-non-folio-compound-page.patch