diff --git a/mm/mremap.c b/mm/mremap.c
index 7c368440fafe..058dd66fe1d7 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1275,7 +1275,8 @@ static int copy_vma_and_data(struct vma_remap_struct *vrm,
 	PAGETABLE_MOVE(pmc, NULL, NULL, vrm->addr, vrm->new_addr, vrm->old_len);
 
 	new_vma = copy_vma(&vma, vrm->new_addr, vrm->new_len, new_pgoff,
-			   new_anon_pgoff, &pmc.need_rmap_locks);
+			   new_anon_pgoff, &pmc.need_rmap_locks,
+			   vrm->flags & MREMAP_DONTUNMAP);
 	if (!new_vma) {
 		vrm_uncharge(vrm);
 		*new_vma_ptr = NULL;
@@ -1335,6 +1336,9 @@ static void dontunmap_complete(struct vma_remap_struct *vrm,
 	unsigned long old_start = vma->vm_start;
 	unsigned long old_end = vma->vm_end;
 
+	/* Self-merge is disallowed. */
+	VM_WARN_ON_ONCE(new_vma == vma);
+
 	/* We always clear VMA_LOCKED[ONFAULT]_BIT on the old VMA. */
 	vma_clear_flags_mask(vma, VMA_LOCKED_MASK);
 
@@ -1342,7 +1346,7 @@ static void dontunmap_complete(struct vma_remap_struct *vrm,
 	 * anon_vma links of the old vma is no longer needed after its page
 	 * table has been moved.
 	 */
-	if (new_vma != vma && start == old_start && end == old_end) {
+	if (start == old_start && end == old_end) {
 		const pgoff_t pgoff_unfaulted = vma->vm_start >> PAGE_SHIFT;
 
 		unlink_anon_vmas(vma);
diff --git a/mm/vma.c b/mm/vma.c
index 6cde67883fb0..d8308c319daa 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -1943,7 +1943,7 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
  */
 struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 	unsigned long addr, unsigned long len, pgoff_t pgoff,
-	pgoff_t anon_pgoff, bool *need_rmap_locks)
+	pgoff_t anon_pgoff, bool *need_rmap_locks, bool keep_source)
 {
 	struct vm_area_struct *vma = *vmap;
 	unsigned long old_vma_start = vma->vm_start;
@@ -1981,6 +1981,21 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 	vmg.pgoff = pgoff;
 	vmg.anon_pgoff = anon_pgoff;
 	vmg.next = vma_iter_next_rewind(&vmi, NULL);
+
+	/*
+	 * If the original VMA is kept (MREMAP_DONTUNMAP), the source and
+	 * destination VMA must be treated distinctly.
+	 *
+	 * A merge violates this, so in this case disallow a self-merge.
+	 */
+	if (can_self_merge && keep_source) {
+		if (vmg.prev == vma)
+			vmg.prev = NULL;
+		if (vmg.next == vma)
+			vmg.next = NULL;
+		can_self_merge = false;
+	}
+
 	new_vma = vma_merge_copied_range(&vmg);
 
 	if (new_vma) {
diff --git a/mm/vma.h b/mm/vma.h
index 024fabe63560..39514fac72fc 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -535,7 +535,7 @@ void unlink_file_vma_batch_add(struct unlink_vma_file_batch *vb,
 
 struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 	unsigned long addr, unsigned long len, pgoff_t pgoff,
-	pgoff_t anon_pgoff, bool *need_rmap_locks);
+	pgoff_t anon_pgoff, bool *need_rmap_locks, bool keep_source);
 
 struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma);
 
diff --git a/tools/testing/vma/tests/vma.c b/tools/testing/vma/tests/vma.c
index c8ef7b8cd46b..e973e0a6d1a8 100644
--- a/tools/testing/vma/tests/vma.c
+++ b/tools/testing/vma/tests/vma.c
@@ -40,7 +40,7 @@ static bool test_copy_vma(void)
 	vma = alloc_and_link_vma(&mm, 0x1000, 0x2000, 1, vma_flags);
 	vma_set_anonymous(vma);
 	vma_orig = vma;
-	vma_new = copy_vma(&vma, 0x2000, 0x1000, 1, 1, &need_locks);
+	vma_new = copy_vma(&vma, 0x2000, 0x1000, 1, 1, &need_locks, false);
 	ASSERT_EQ(vma_new, vma_orig);
 	ASSERT_EQ(vma, vma_orig);
 	ASSERT_EQ(vma_new->vm_start, 0x1000);
@@ -53,7 +53,7 @@ static bool test_copy_vma(void)
 	vma = alloc_and_link_vma(&mm, 0x2000, 0x3000, 2, vma_flags);
 	vma_set_anonymous(vma);
 	vma_orig = vma;
-	vma_new = copy_vma(&vma, 0x1000, 0x1000, 2, 2, &need_locks);
+	vma_new = copy_vma(&vma, 0x1000, 0x1000, 2, 2, &need_locks, false);
 	ASSERT_EQ(vma_new, vma_orig);
 	ASSERT_EQ(vma, vma_orig);
 	ASSERT_EQ(vma_new->vm_start, 0x1000);
@@ -71,7 +71,7 @@ static bool test_copy_vma(void)
 	vma = alloc_and_link_vma(&mm, 0x3000, 0x4000, 3, vma_flags);
 	vma_set_anonymous(vma);
 	vma_orig = vma;
-	vma_new = copy_vma(&vma, 0x2000, 0x1000, 3, 3, &need_locks);
+	vma_new = copy_vma(&vma, 0x2000, 0x1000, 3, 3, &need_locks, false);
 	ASSERT_NE(vma_new, vma_orig);
 	ASSERT_EQ(vma_new, vma);
 	ASSERT_EQ(vma_new->vm_start, 0x1000);
@@ -82,7 +82,7 @@ static bool test_copy_vma(void)
 	/* Move backwards and do not merge. */
 
 	vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, vma_flags);
-	vma_new = copy_vma(&vma, 0, 0x2000, 0, 3, &need_locks);
+	vma_new = copy_vma(&vma, 0, 0x2000, 0, 3, &need_locks, false);
 	ASSERT_NE(vma_new, vma);
 	ASSERT_EQ(vma_new->vm_start, 0);
 	ASSERT_EQ(vma_new->vm_end, 0x2000);
@@ -95,7 +95,7 @@ static bool test_copy_vma(void)
 
 	vma = alloc_and_link_vma(&mm, 0, 0x2000, 0, vma_flags);
 	vma_next = alloc_and_link_vma(&mm, 0x6000, 0x8000, 6, vma_flags);
-	vma_new = copy_vma(&vma, 0x4000, 0x2000, 4, 4, &need_locks);
+	vma_new = copy_vma(&vma, 0x4000, 0x2000, 4, 4, &need_locks, false);
 	vma_assert_attached(vma_new);
 
 	ASSERT_EQ(vma_new, vma_next);