[to-be-updated] tools-testing-selftests-mm-test-virtual-page-offset-merge-behaviour.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: tools/testing/selftests/mm: test virtual page offset merge behaviour
has been removed from the -mm tree.  Its filename was
     tools-testing-selftests-mm-test-virtual-page-offset-merge-behaviour.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: tools/testing/selftests/mm: test virtual page offset merge behaviour
Date: Mon, 20 Jul 2026 15:38:37 +0100

While maintaining virtual page offsets for VMAs has no impact for most
merge cases, it does impact MAP_PRIVATE-mapped file-backed mappings which
happen to have matching page offset but not matching virtual page offset.

Assert this behaviour by attempting to map an unfaulted MAP_PRIVATE-memfd
region with a faulted one with compatible file page offsets but
incompatible virtual page offsets.

Link: https://lore.kernel.org/20260720-b4-scalable-cow-virt-pgoff-v2-11-2d549757a76f@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Matthew Brost <matthew.brost@intel.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: Nico Pache <npache@redhat.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/merge.c |   57 +++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

--- a/tools/testing/selftests/mm/merge.c~tools-testing-selftests-mm-test-virtual-page-offset-merge-behaviour
+++ a/tools/testing/selftests/mm/merge.c
@@ -1305,6 +1305,63 @@ TEST_F(merge, merge_vmas_with_mseal)
 	ASSERT_EQ(procmap->query.vma_end, (unsigned long)ptr + 2 * page_size);
 }
 
+TEST_F(merge, virt_and_page_offset_mismatch_memfd)
+{
+	struct procmap_fd *procmap = &self->procmap;
+	unsigned int page_size = self->page_size;
+	char *carveout = self->carveout;
+	char *ptr, *ptr2;
+	int fd;
+
+	/* Create a 10 page memfd descriptor. */
+	fd = memfd_create("virt_page_offset_test", MFD_CLOEXEC);
+	ASSERT_NE(fd, -1);
+	ASSERT_EQ(ftruncate(fd, 10 * page_size), 0);
+
+	/* Map a region using the memfd at page offset 0. */
+	ptr = mmap(carveout, 5 * page_size, PROT_READ | PROT_WRITE,
+		   MAP_FIXED | MAP_PRIVATE, fd, 0);
+	ASSERT_NE(ptr, MAP_FAILED);
+
+	/*
+	 * Map another separately, and fault in, at page offset 5:
+	 *
+	 * |-----------|           |---------|
+	 * | unfaulted |           | faulted |
+	 * |-----------|           |---------|
+	 */
+	ptr2 = mmap(&carveout[10 * page_size], 5 * page_size,
+		    PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE,
+		    fd, 5 * page_size);
+	ASSERT_NE(ptr2, MAP_FAILED);
+	ptr2[0] = 'x';
+
+	/*
+	 * Now move it in place:
+	 *
+	 *                   |----------|
+	 *                   |          |
+	 *                   v          |
+	 * |-----------|           |---------|
+	 * | unfaulted |           | faulted |
+	 * |-----------|           |---------|
+	 *
+	 * Because virtual page offset of the faulted region is now
+	 * &carveout[10 * page_size], despite the two regions being mergeable
+	 * due to file page offset, they are NOT mergeable due to virtual page
+	 * offset.
+	 */
+	ptr2 = sys_mremap(ptr2, 5 * page_size, 5 * page_size,
+			  MREMAP_MAYMOVE | MREMAP_FIXED,
+			  &carveout[5 * page_size]);
+	ASSERT_NE(ptr2, MAP_FAILED);
+
+	/* Assert that they did not merge. */
+	ASSERT_TRUE(find_vma_procmap(procmap, ptr));
+	ASSERT_EQ(procmap->query.vma_start, (unsigned long)ptr);
+	ASSERT_EQ(procmap->query.vma_end, (unsigned long)ptr + 5 * page_size);
+}
+
 TEST_F(merge_with_fork, mremap_faulted_to_unfaulted_prev)
 {
 	struct procmap_fd *procmap = &self->procmap;
_

Patches currently in -mm which might be from ljs@kernel.org are

x86-mm-pat-acquire-init_mm-write-lock-on-collapse-to-avoid-uaf.patch
x86-mm-pat-acquire-init_mm-read-lock-on-attribute-change-to-avoid-uaf.patch
x86-mm-pat-allocate-split-page-tables-as-kernel-page-tables.patch
mm-introduce-vma_flags_can_grow-and-vma_can_grow.patch
mm-vma-update-do_mmap-to-use-vma_flags_t.patch
mm-convert-__get_unmapped_area-to-use-vma_flags_t.patch
mm-update-generic_get_unmapped_area-to-use-vma_flags_t.patch
mm-prefer-mm-def_vma_flags-in-mm-logic.patch
mm-vma-convert-vm_pgprot_modify-to-use-vma_flags_t-and-rename.patch
mm-vma-rename-vma_get_page_prot-to-vma_flags_to_page_prot.patch
mm-introduce-vma_get_page_prot-and-use-it.patch
mm-vma-update-create_init_stack_vma-to-use-vma_flags_t.patch
mm-vma-convert-miscellaneous-uses-of-vma-flags-in-core-mm.patch
mm-mlock-convert-mlock-code-to-use-vma_flags_t.patch
mm-mprotect-convert-mprotect-code-to-use-vma_flags_t.patch
mm-mremap-convert-mremap-code-to-use-vma_flags_t.patch
mm-mseal-remove-superfluous-comments-fix-confusion-around-mm.patch
mm-mseal-limit-scope-of-mseal-address-zero-to-address-zero.patch
mm-mseal-remove-further-superfluous-comments-do_mseal.patch
mm-vma-only-permit-map_private-dev-zero-to-be-mapped-anonymous.patch
mm-vma-make-map_private-mapped-dev-zero-mappings-truly-anonymous.patch
tools-testing-vma-add-test-to-assert-map_private-dev-zero-is-anon.patch
tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch
mm-add-some-missing-includes-to-mm-local-headers.patch