[PATCH v4 7/9] tools/testing/vma: add VMA sticky userland tests

18 Nov 2025

Modify existing merge new/existing userland VMA tests to assert that
sticky VMA flags behave as expected.
We do so by generating every possible permutation of VMAs being
manipulated being sticky/not sticky and asserting that VMA flags with this
property retain are retained upon merge.
Signed-off-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com
---
 tools/testing/vma/vma.c | 89 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 79 insertions(+), 10 deletions(-)

diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
index fd37ce3b2628..be79ab2ea44b 100644
--- a/tools/testing/vma/vma.c
+++ b/tools/testing/vma/vma.c
@@ -48,6 +48,8 @@ static struct anon_vma dummy_anon_vma;
 #define ASSERT_EQ(_val1, _val2) ASSERT_TRUE((_val1) == (_val2))
 #define ASSERT_NE(_val1, _val2) ASSERT_TRUE((_val1) != (_val2))
+#define IS_SET(_val, _flags) ((_val & _flags) == _flags)
+
 static struct task_struct __current;
struct task_struct *get_current(void)
@@ -442,7 +444,7 @@ static bool test_simple_shrink(void)
    return true;
 }
-static bool test_merge_new(void)
+static bool __test_merge_new(bool is_sticky, bool a_is_sticky, bool b_is_sticky, bool c_is_sticky)
 {
    vm_flags_t vm_flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
    struct mm_struct mm = {};
@@ -470,23 +472,32 @@ static bool test_merge_new(void)
    struct vm_area_struct *vma, *vma_a, *vma_b, *vma_c, *vma_d;
    bool merged;
+	if (is_sticky)
+		vm_flags |= VM_STICKY;
+
    /*
     * 0123456789abc
     * AA B       CC
     */
    vma_a = alloc_and_link_vma(&mm, 0, 0x2000, 0, vm_flags);
    ASSERT_NE(vma_a, NULL);
+	if (a_is_sticky)
+		vm_flags_set(vma_a, VM_STICKY);
    /* We give each VMA a single avc so we can test anon_vma duplication. */
    INIT_LIST_HEAD(&vma_a->anon_vma_chain);
    list_add(&dummy_anon_vma_chain_a.same_vma, &vma_a->anon_vma_chain);
vma_b = alloc_and_link_vma(&mm, 0x3000, 0x4000, 3, vm_flags);
    ASSERT_NE(vma_b, NULL);
+	if (b_is_sticky)
+		vm_flags_set(vma_b, VM_STICKY);
    INIT_LIST_HEAD(&vma_b->anon_vma_chain);
    list_add(&dummy_anon_vma_chain_b.same_vma, &vma_b->anon_vma_chain);
vma_c = alloc_and_link_vma(&mm, 0xb000, 0xc000, 0xb, vm_flags);
    ASSERT_NE(vma_c, NULL);
+	if (c_is_sticky)
+		vm_flags_set(vma_c, VM_STICKY);
    INIT_LIST_HEAD(&vma_c->anon_vma_chain);
    list_add(&dummy_anon_vma_chain_c.same_vma, &vma_c->anon_vma_chain);
@@ -521,6 +532,8 @@ static bool test_merge_new(void)
    ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 3);
+	if (is_sticky || a_is_sticky || b_is_sticky)
+		ASSERT_TRUE(IS_SET(vma->vm_flags, VM_STICKY));
/*
     * Merge to PREVIOUS VMA.
@@ -538,6 +551,8 @@ static bool test_merge_new(void)
    ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 3);
+	if (is_sticky || a_is_sticky)
+		ASSERT_TRUE(IS_SET(vma->vm_flags, VM_STICKY));
/*
     * Merge to NEXT VMA.
@@ -557,6 +572,8 @@ static bool test_merge_new(void)
    ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 3);
+	if (is_sticky) /* D uses is_sticky. */
+		ASSERT_TRUE(IS_SET(vma->vm_flags, VM_STICKY));
/*
     * Merge BOTH sides.
@@ -575,6 +592,8 @@ static bool test_merge_new(void)
    ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 2);
+	if (is_sticky || a_is_sticky)
+		ASSERT_TRUE(IS_SET(vma->vm_flags, VM_STICKY));
/*
     * Merge to NEXT VMA.
@@ -593,6 +612,8 @@ static bool test_merge_new(void)
    ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 2);
+	if (is_sticky || c_is_sticky)
+		ASSERT_TRUE(IS_SET(vma->vm_flags, VM_STICKY));
/*
     * Merge BOTH sides.
@@ -610,6 +631,8 @@ static bool test_merge_new(void)
    ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 1);
+	if (is_sticky || a_is_sticky || c_is_sticky)
+		ASSERT_TRUE(IS_SET(vma->vm_flags, VM_STICKY));
/*
     * Final state.
@@ -638,6 +661,20 @@ static bool test_merge_new(void)
    return true;
 }
+static bool test_merge_new(void)
+{
+	int i, j, k, l;
+
+	/* Generate every possible permutation of sticky flags. */
+	for (i = 0; i < 2; i++)
+		for (j = 0; j < 2; j++)
+			for (k = 0; k < 2; k++)
+				for (l = 0; l < 2; l++)
+					ASSERT_TRUE(__test_merge_new(i, j, k, l));
+
+	return true;
+}
+
 static bool test_vma_merge_special_flags(void)
 {
    vm_flags_t vm_flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
@@ -974,9 +1011,11 @@ static bool test_vma_merge_new_with_close(void)
    return true;
 }
-static bool test_merge_existing(void)
+static bool __test_merge_existing(bool prev_is_sticky, bool middle_is_sticky, bool next_is_sticky)
 {
    vm_flags_t vm_flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+	vm_flags_t prev_flags = vm_flags;
+	vm_flags_t next_flags = vm_flags;
    struct mm_struct mm = {};
    VMA_ITERATOR(vmi, &mm, 0);
    struct vm_area_struct *vma, *vma_prev, *vma_next;
@@ -989,6 +1028,13 @@ static bool test_merge_existing(void)
    };
    struct anon_vma_chain avc = {};
+	if (prev_is_sticky)
+		prev_flags |= VM_STICKY;
+	if (middle_is_sticky)
+		vm_flags |= VM_STICKY;
+	if (next_is_sticky)
+		next_flags |= VM_STICKY;
+
    /*
     * Merge right case - partial span.
     *
@@ -1001,7 +1047,7 @@ static bool test_merge_existing(void)
     */
    vma = alloc_and_link_vma(&mm, 0x2000, 0x6000, 2, vm_flags);
    vma->vm_ops = &vm_ops; /* This should have no impact. */
-	vma_next = alloc_and_link_vma(&mm, 0x6000, 0x9000, 6, vm_flags);
+	vma_next = alloc_and_link_vma(&mm, 0x6000, 0x9000, 6, next_flags);
    vma_next->vm_ops = &vm_ops; /* This should have no impact. */
    vmg_set_range_anon_vma(&vmg, 0x3000, 0x6000, 3, vm_flags, &dummy_anon_vma);
    vmg.middle = vma;
@@ -1019,6 +1065,8 @@ static bool test_merge_existing(void)
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_TRUE(vma_write_started(vma_next));
    ASSERT_EQ(mm.map_count, 2);
+	if (middle_is_sticky || next_is_sticky)
+		ASSERT_TRUE(IS_SET(vma_next->vm_flags, VM_STICKY));
/* Clear down and reset. */
    ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
@@ -1034,7 +1082,7 @@ static bool test_merge_existing(void)
     *   NNNNNNN
     */
    vma = alloc_and_link_vma(&mm, 0x2000, 0x6000, 2, vm_flags);
-	vma_next = alloc_and_link_vma(&mm, 0x6000, 0x9000, 6, vm_flags);
+	vma_next = alloc_and_link_vma(&mm, 0x6000, 0x9000, 6, next_flags);
    vma_next->vm_ops = &vm_ops; /* This should have no impact. */
    vmg_set_range_anon_vma(&vmg, 0x2000, 0x6000, 2, vm_flags, &dummy_anon_vma);
    vmg.middle = vma;
@@ -1047,6 +1095,8 @@ static bool test_merge_existing(void)
    ASSERT_EQ(vma_next->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma_next));
    ASSERT_EQ(mm.map_count, 1);
+	if (middle_is_sticky || next_is_sticky)
+		ASSERT_TRUE(IS_SET(vma_next->vm_flags, VM_STICKY));
/* Clear down and reset. We should have deleted vma. */
    ASSERT_EQ(cleanup_mm(&mm, &vmi), 1);
@@ -1061,7 +1111,7 @@ static bool test_merge_existing(void)
     * 0123456789
     * PPPPPPV
     */
-	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, vm_flags);
+	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, prev_flags);
    vma_prev->vm_ops = &vm_ops; /* This should have no impact. */
    vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, vm_flags);
    vma->vm_ops = &vm_ops; /* This should have no impact. */
@@ -1081,6 +1131,8 @@ static bool test_merge_existing(void)
    ASSERT_TRUE(vma_write_started(vma_prev));
    ASSERT_TRUE(vma_write_started(vma));
    ASSERT_EQ(mm.map_count, 2);
+	if (prev_is_sticky || middle_is_sticky)
+		ASSERT_TRUE(IS_SET(vma_prev->vm_flags, VM_STICKY));
/* Clear down and reset. */
    ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
@@ -1095,7 +1147,7 @@ static bool test_merge_existing(void)
     * 0123456789
     * PPPPPPP
     */
-	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, vm_flags);
+	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, prev_flags);
    vma_prev->vm_ops = &vm_ops; /* This should have no impact. */
    vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, vm_flags);
    vmg_set_range_anon_vma(&vmg, 0x3000, 0x7000, 3, vm_flags, &dummy_anon_vma);
@@ -1110,6 +1162,8 @@ static bool test_merge_existing(void)
    ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma_prev));
    ASSERT_EQ(mm.map_count, 1);
+	if (prev_is_sticky || middle_is_sticky)
+		ASSERT_TRUE(IS_SET(vma_prev->vm_flags, VM_STICKY));
/* Clear down and reset. We should have deleted vma. */
    ASSERT_EQ(cleanup_mm(&mm, &vmi), 1);
@@ -1124,10 +1178,10 @@ static bool test_merge_existing(void)
     * 0123456789
     * PPPPPPPPPP
     */
-	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, vm_flags);
+	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, prev_flags);
    vma_prev->vm_ops = &vm_ops; /* This should have no impact. */
    vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, vm_flags);
-	vma_next = alloc_and_link_vma(&mm, 0x7000, 0x9000, 7, vm_flags);
+	vma_next = alloc_and_link_vma(&mm, 0x7000, 0x9000, 7, next_flags);
    vmg_set_range_anon_vma(&vmg, 0x3000, 0x7000, 3, vm_flags, &dummy_anon_vma);
    vmg.prev = vma_prev;
    vmg.middle = vma;
@@ -1140,6 +1194,8 @@ static bool test_merge_existing(void)
    ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
    ASSERT_TRUE(vma_write_started(vma_prev));
    ASSERT_EQ(mm.map_count, 1);
+	if (prev_is_sticky || middle_is_sticky || next_is_sticky)
+		ASSERT_TRUE(IS_SET(vma_prev->vm_flags, VM_STICKY));
/* Clear down and reset. We should have deleted prev and next. */
    ASSERT_EQ(cleanup_mm(&mm, &vmi), 1);
@@ -1159,9 +1215,9 @@ static bool test_merge_existing(void)
     * PPPVVVVVNNN
     */
-	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, vm_flags);
+	vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, prev_flags);
    vma = alloc_and_link_vma(&mm, 0x3000, 0x8000, 3, vm_flags);
-	vma_next = alloc_and_link_vma(&mm, 0x8000, 0xa000, 8, vm_flags);
+	vma_next = alloc_and_link_vma(&mm, 0x8000, 0xa000, 8, next_flags);
vmg_set_range(&vmg, 0x4000, 0x5000, 4, vm_flags);
    vmg.prev = vma;
@@ -1204,6 +1260,19 @@ static bool test_merge_existing(void)
    return true;
 }
+static bool test_merge_existing(void)
+{
+	int i, j, k;
+
+	/* Generate every possible permutation of sticky flags. */
+	for (i = 0; i < 2; i++)
+		for (j = 0; j < 2; j++)
+			for (k = 0; k < 2; k++)
+				ASSERT_TRUE(__test_merge_existing(i, j, k));
+
+	return true;
+}
+
 static bool test_anon_vma_non_mergeable(void)
 {
    vm_flags_t vm_flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
-- 
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[PATCH v4 7/9] tools/testing/vma: add VMA sticky userland tests