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-rw-r--r--tools/testing/vma/vma.c1563
1 files changed, 1563 insertions, 0 deletions
diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
new file mode 100644
index 000000000000..c53f220eb6cc
--- /dev/null
+++ b/tools/testing/vma/vma.c
@@ -0,0 +1,1563 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "maple-shared.h"
+#include "vma_internal.h"
+
+/* Include so header guard set. */
+#include "../../../mm/vma.h"
+
+static bool fail_prealloc;
+
+/* Then override vma_iter_prealloc() so we can choose to fail it. */
+#define vma_iter_prealloc(vmi, vma) \
+ (fail_prealloc ? -ENOMEM : mas_preallocate(&(vmi)->mas, (vma), GFP_KERNEL))
+
+/*
+ * Directly import the VMA implementation here. Our vma_internal.h wrapper
+ * provides userland-equivalent functionality for everything vma.c uses.
+ */
+#include "../../../mm/vma.c"
+
+const struct vm_operations_struct vma_dummy_vm_ops;
+static struct anon_vma dummy_anon_vma;
+
+#define ASSERT_TRUE(_expr) \
+ do { \
+ if (!(_expr)) { \
+ fprintf(stderr, \
+ "Assert FAILED at %s:%d:%s(): %s is FALSE.\n", \
+ __FILE__, __LINE__, __FUNCTION__, #_expr); \
+ return false; \
+ } \
+ } while (0)
+#define ASSERT_FALSE(_expr) ASSERT_TRUE(!(_expr))
+#define ASSERT_EQ(_val1, _val2) ASSERT_TRUE((_val1) == (_val2))
+#define ASSERT_NE(_val1, _val2) ASSERT_TRUE((_val1) != (_val2))
+
+static struct task_struct __current;
+
+struct task_struct *get_current(void)
+{
+ return &__current;
+}
+
+/* Helper function to simply allocate a VMA. */
+static struct vm_area_struct *alloc_vma(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end,
+ pgoff_t pgoff,
+ vm_flags_t flags)
+{
+ struct vm_area_struct *ret = vm_area_alloc(mm);
+
+ if (ret == NULL)
+ return NULL;
+
+ ret->vm_start = start;
+ ret->vm_end = end;
+ ret->vm_pgoff = pgoff;
+ ret->__vm_flags = flags;
+
+ return ret;
+}
+
+/* Helper function to allocate a VMA and link it to the tree. */
+static struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end,
+ pgoff_t pgoff,
+ vm_flags_t flags)
+{
+ struct vm_area_struct *vma = alloc_vma(mm, start, end, pgoff, flags);
+
+ if (vma == NULL)
+ return NULL;
+
+ if (vma_link(mm, vma)) {
+ vm_area_free(vma);
+ return NULL;
+ }
+
+ /*
+ * Reset this counter which we use to track whether writes have
+ * begun. Linking to the tree will have caused this to be incremented,
+ * which means we will get a false positive otherwise.
+ */
+ vma->vm_lock_seq = -1;
+
+ return vma;
+}
+
+/* Helper function which provides a wrapper around a merge new VMA operation. */
+static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg)
+{
+ /*
+ * For convenience, get prev and next VMAs. Which the new VMA operation
+ * requires.
+ */
+ vmg->next = vma_next(vmg->vmi);
+ vmg->prev = vma_prev(vmg->vmi);
+ vma_iter_next_range(vmg->vmi);
+
+ return vma_merge_new_range(vmg);
+}
+
+/*
+ * Helper function which provides a wrapper around a merge existing VMA
+ * operation.
+ */
+static struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg)
+{
+ return vma_merge_existing_range(vmg);
+}
+
+/*
+ * Helper function which provides a wrapper around the expansion of an existing
+ * VMA.
+ */
+static int expand_existing(struct vma_merge_struct *vmg)
+{
+ return vma_expand(vmg);
+}
+
+/*
+ * Helper function to reset merge state the associated VMA iterator to a
+ * specified new range.
+ */
+static void vmg_set_range(struct vma_merge_struct *vmg, unsigned long start,
+ unsigned long end, pgoff_t pgoff, vm_flags_t flags)
+{
+ vma_iter_set(vmg->vmi, start);
+
+ vmg->prev = NULL;
+ vmg->next = NULL;
+ vmg->vma = NULL;
+
+ vmg->start = start;
+ vmg->end = end;
+ vmg->pgoff = pgoff;
+ vmg->flags = flags;
+}
+
+/*
+ * Helper function to try to merge a new VMA.
+ *
+ * Update vmg and the iterator for it and try to merge, otherwise allocate a new
+ * VMA, link it to the maple tree and return it.
+ */
+static struct vm_area_struct *try_merge_new_vma(struct mm_struct *mm,
+ struct vma_merge_struct *vmg,
+ unsigned long start, unsigned long end,
+ pgoff_t pgoff, vm_flags_t flags,
+ bool *was_merged)
+{
+ struct vm_area_struct *merged;
+
+ vmg_set_range(vmg, start, end, pgoff, flags);
+
+ merged = merge_new(vmg);
+ if (merged) {
+ *was_merged = true;
+ ASSERT_EQ(vmg->state, VMA_MERGE_SUCCESS);
+ return merged;
+ }
+
+ *was_merged = false;
+
+ ASSERT_EQ(vmg->state, VMA_MERGE_NOMERGE);
+
+ return alloc_and_link_vma(mm, start, end, pgoff, flags);
+}
+
+/*
+ * Helper function to reset the dummy anon_vma to indicate it has not been
+ * duplicated.
+ */
+static void reset_dummy_anon_vma(void)
+{
+ dummy_anon_vma.was_cloned = false;
+ dummy_anon_vma.was_unlinked = false;
+}
+
+/*
+ * Helper function to remove all VMAs and destroy the maple tree associated with
+ * a virtual address space. Returns a count of VMAs in the tree.
+ */
+static int cleanup_mm(struct mm_struct *mm, struct vma_iterator *vmi)
+{
+ struct vm_area_struct *vma;
+ int count = 0;
+
+ fail_prealloc = false;
+ reset_dummy_anon_vma();
+
+ vma_iter_set(vmi, 0);
+ for_each_vma(*vmi, vma) {
+ vm_area_free(vma);
+ count++;
+ }
+
+ mtree_destroy(&mm->mm_mt);
+ mm->map_count = 0;
+ return count;
+}
+
+/* Helper function to determine if VMA has had vma_start_write() performed. */
+static bool vma_write_started(struct vm_area_struct *vma)
+{
+ int seq = vma->vm_lock_seq;
+
+ /* We reset after each check. */
+ vma->vm_lock_seq = -1;
+
+ /* The vma_start_write() stub simply increments this value. */
+ return seq > -1;
+}
+
+/* Helper function providing a dummy vm_ops->close() method.*/
+static void dummy_close(struct vm_area_struct *)
+{
+}
+
+static bool test_simple_merge(void)
+{
+ struct vm_area_struct *vma;
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ struct vm_area_struct *vma_left = alloc_vma(&mm, 0, 0x1000, 0, flags);
+ struct vm_area_struct *vma_right = alloc_vma(&mm, 0x2000, 0x3000, 2, flags);
+ VMA_ITERATOR(vmi, &mm, 0x1000);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ .start = 0x1000,
+ .end = 0x2000,
+ .flags = flags,
+ .pgoff = 1,
+ };
+
+ ASSERT_FALSE(vma_link(&mm, vma_left));
+ ASSERT_FALSE(vma_link(&mm, vma_right));
+
+ vma = merge_new(&vmg);
+ ASSERT_NE(vma, NULL);
+
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x3000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->vm_flags, flags);
+
+ vm_area_free(vma);
+ mtree_destroy(&mm.mm_mt);
+
+ return true;
+}
+
+static bool test_simple_modify(void)
+{
+ struct vm_area_struct *vma;
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ struct vm_area_struct *init_vma = alloc_vma(&mm, 0, 0x3000, 0, flags);
+ VMA_ITERATOR(vmi, &mm, 0x1000);
+
+ ASSERT_FALSE(vma_link(&mm, init_vma));
+
+ /*
+ * The flags will not be changed, the vma_modify_flags() function
+ * performs the merge/split only.
+ */
+ vma = vma_modify_flags(&vmi, init_vma, init_vma,
+ 0x1000, 0x2000, VM_READ | VM_MAYREAD);
+ ASSERT_NE(vma, NULL);
+ /* We modify the provided VMA, and on split allocate new VMAs. */
+ ASSERT_EQ(vma, init_vma);
+
+ ASSERT_EQ(vma->vm_start, 0x1000);
+ ASSERT_EQ(vma->vm_end, 0x2000);
+ ASSERT_EQ(vma->vm_pgoff, 1);
+
+ /*
+ * Now walk through the three split VMAs and make sure they are as
+ * expected.
+ */
+
+ vma_iter_set(&vmi, 0);
+ vma = vma_iter_load(&vmi);
+
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x1000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+
+ vm_area_free(vma);
+ vma_iter_clear(&vmi);
+
+ vma = vma_next(&vmi);
+
+ ASSERT_EQ(vma->vm_start, 0x1000);
+ ASSERT_EQ(vma->vm_end, 0x2000);
+ ASSERT_EQ(vma->vm_pgoff, 1);
+
+ vm_area_free(vma);
+ vma_iter_clear(&vmi);
+
+ vma = vma_next(&vmi);
+
+ ASSERT_EQ(vma->vm_start, 0x2000);
+ ASSERT_EQ(vma->vm_end, 0x3000);
+ ASSERT_EQ(vma->vm_pgoff, 2);
+
+ vm_area_free(vma);
+ mtree_destroy(&mm.mm_mt);
+
+ return true;
+}
+
+static bool test_simple_expand(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ struct vm_area_struct *vma = alloc_vma(&mm, 0, 0x1000, 0, flags);
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .vmi = &vmi,
+ .vma = vma,
+ .start = 0,
+ .end = 0x3000,
+ .pgoff = 0,
+ };
+
+ ASSERT_FALSE(vma_link(&mm, vma));
+
+ ASSERT_FALSE(expand_existing(&vmg));
+
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x3000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+
+ vm_area_free(vma);
+ mtree_destroy(&mm.mm_mt);
+
+ return true;
+}
+
+static bool test_simple_shrink(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ struct vm_area_struct *vma = alloc_vma(&mm, 0, 0x3000, 0, flags);
+ VMA_ITERATOR(vmi, &mm, 0);
+
+ ASSERT_FALSE(vma_link(&mm, vma));
+
+ ASSERT_FALSE(vma_shrink(&vmi, vma, 0, 0x1000, 0));
+
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x1000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+
+ vm_area_free(vma);
+ mtree_destroy(&mm.mm_mt);
+
+ return true;
+}
+
+static bool test_merge_new(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain_a = {
+ .anon_vma = &dummy_anon_vma,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain_b = {
+ .anon_vma = &dummy_anon_vma,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain_c = {
+ .anon_vma = &dummy_anon_vma,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain_d = {
+ .anon_vma = &dummy_anon_vma,
+ };
+ const struct vm_operations_struct vm_ops = {
+ .close = dummy_close,
+ };
+ int count;
+ struct vm_area_struct *vma, *vma_a, *vma_b, *vma_c, *vma_d;
+ bool merged;
+
+ /*
+ * 0123456789abc
+ * AA B CC
+ */
+ vma_a = alloc_and_link_vma(&mm, 0, 0x2000, 0, flags);
+ ASSERT_NE(vma_a, NULL);
+ /* 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, flags);
+ ASSERT_NE(vma_b, NULL);
+ 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, flags);
+ ASSERT_NE(vma_c, NULL);
+ INIT_LIST_HEAD(&vma_c->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain_c.same_vma, &vma_c->anon_vma_chain);
+
+ /*
+ * NO merge.
+ *
+ * 0123456789abc
+ * AA B ** CC
+ */
+ vma_d = try_merge_new_vma(&mm, &vmg, 0x7000, 0x9000, 7, flags, &merged);
+ ASSERT_NE(vma_d, NULL);
+ INIT_LIST_HEAD(&vma_d->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain_d.same_vma, &vma_d->anon_vma_chain);
+ ASSERT_FALSE(merged);
+ ASSERT_EQ(mm.map_count, 4);
+
+ /*
+ * Merge BOTH sides.
+ *
+ * 0123456789abc
+ * AA*B DD CC
+ */
+ vma_a->vm_ops = &vm_ops; /* This should have no impact. */
+ vma_b->anon_vma = &dummy_anon_vma;
+ vma = try_merge_new_vma(&mm, &vmg, 0x2000, 0x3000, 2, flags, &merged);
+ ASSERT_EQ(vma, vma_a);
+ /* Merge with A, delete B. */
+ ASSERT_TRUE(merged);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x4000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 3);
+
+ /*
+ * Merge to PREVIOUS VMA.
+ *
+ * 0123456789abc
+ * AAAA* DD CC
+ */
+ vma = try_merge_new_vma(&mm, &vmg, 0x4000, 0x5000, 4, flags, &merged);
+ ASSERT_EQ(vma, vma_a);
+ /* Extend A. */
+ ASSERT_TRUE(merged);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x5000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 3);
+
+ /*
+ * Merge to NEXT VMA.
+ *
+ * 0123456789abc
+ * AAAAA *DD CC
+ */
+ vma_d->anon_vma = &dummy_anon_vma;
+ vma_d->vm_ops = &vm_ops; /* This should have no impact. */
+ vma = try_merge_new_vma(&mm, &vmg, 0x6000, 0x7000, 6, flags, &merged);
+ ASSERT_EQ(vma, vma_d);
+ /* Prepend. */
+ ASSERT_TRUE(merged);
+ ASSERT_EQ(vma->vm_start, 0x6000);
+ ASSERT_EQ(vma->vm_end, 0x9000);
+ ASSERT_EQ(vma->vm_pgoff, 6);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 3);
+
+ /*
+ * Merge BOTH sides.
+ *
+ * 0123456789abc
+ * AAAAA*DDD CC
+ */
+ vma_d->vm_ops = NULL; /* This would otherwise degrade the merge. */
+ vma = try_merge_new_vma(&mm, &vmg, 0x5000, 0x6000, 5, flags, &merged);
+ ASSERT_EQ(vma, vma_a);
+ /* Merge with A, delete D. */
+ ASSERT_TRUE(merged);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x9000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 2);
+
+ /*
+ * Merge to NEXT VMA.
+ *
+ * 0123456789abc
+ * AAAAAAAAA *CC
+ */
+ vma_c->anon_vma = &dummy_anon_vma;
+ vma = try_merge_new_vma(&mm, &vmg, 0xa000, 0xb000, 0xa, flags, &merged);
+ ASSERT_EQ(vma, vma_c);
+ /* Prepend C. */
+ ASSERT_TRUE(merged);
+ ASSERT_EQ(vma->vm_start, 0xa000);
+ ASSERT_EQ(vma->vm_end, 0xc000);
+ ASSERT_EQ(vma->vm_pgoff, 0xa);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 2);
+
+ /*
+ * Merge BOTH sides.
+ *
+ * 0123456789abc
+ * AAAAAAAAA*CCC
+ */
+ vma = try_merge_new_vma(&mm, &vmg, 0x9000, 0xa000, 0x9, flags, &merged);
+ ASSERT_EQ(vma, vma_a);
+ /* Extend A and delete C. */
+ ASSERT_TRUE(merged);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0xc000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 1);
+
+ /*
+ * Final state.
+ *
+ * 0123456789abc
+ * AAAAAAAAAAAAA
+ */
+
+ count = 0;
+ vma_iter_set(&vmi, 0);
+ for_each_vma(vmi, vma) {
+ ASSERT_NE(vma, NULL);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0xc000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->anon_vma, &dummy_anon_vma);
+
+ vm_area_free(vma);
+ count++;
+ }
+
+ /* Should only have one VMA left (though freed) after all is done.*/
+ ASSERT_EQ(count, 1);
+
+ mtree_destroy(&mm.mm_mt);
+ return true;
+}
+
+static bool test_vma_merge_special_flags(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ vm_flags_t special_flags[] = { VM_IO, VM_DONTEXPAND, VM_PFNMAP, VM_MIXEDMAP };
+ vm_flags_t all_special_flags = 0;
+ int i;
+ struct vm_area_struct *vma_left, *vma;
+
+ /* Make sure there aren't new VM_SPECIAL flags. */
+ for (i = 0; i < ARRAY_SIZE(special_flags); i++) {
+ all_special_flags |= special_flags[i];
+ }
+ ASSERT_EQ(all_special_flags, VM_SPECIAL);
+
+ /*
+ * 01234
+ * AAA
+ */
+ vma_left = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ ASSERT_NE(vma_left, NULL);
+
+ /* 1. Set up new VMA with special flag that would otherwise merge. */
+
+ /*
+ * 01234
+ * AAA*
+ *
+ * This should merge if not for the VM_SPECIAL flag.
+ */
+ vmg_set_range(&vmg, 0x3000, 0x4000, 3, flags);
+ for (i = 0; i < ARRAY_SIZE(special_flags); i++) {
+ vm_flags_t special_flag = special_flags[i];
+
+ vma_left->__vm_flags = flags | special_flag;
+ vmg.flags = flags | special_flag;
+ vma = merge_new(&vmg);
+ ASSERT_EQ(vma, NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+ }
+
+ /* 2. Modify VMA with special flag that would otherwise merge. */
+
+ /*
+ * 01234
+ * AAAB
+ *
+ * Create a VMA to modify.
+ */
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x4000, 3, flags);
+ ASSERT_NE(vma, NULL);
+ vmg.vma = vma;
+
+ for (i = 0; i < ARRAY_SIZE(special_flags); i++) {
+ vm_flags_t special_flag = special_flags[i];
+
+ vma_left->__vm_flags = flags | special_flag;
+ vmg.flags = flags | special_flag;
+ vma = merge_existing(&vmg);
+ ASSERT_EQ(vma, NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+ }
+
+ cleanup_mm(&mm, &vmi);
+ return true;
+}
+
+static bool test_vma_merge_with_close(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ const struct vm_operations_struct vm_ops = {
+ .close = dummy_close,
+ };
+ struct vm_area_struct *vma_prev, *vma_next, *vma;
+
+ /*
+ * When merging VMAs we are not permitted to remove any VMA that has a
+ * vm_ops->close() hook.
+ *
+ * Considering the two possible adjacent VMAs to which a VMA can be
+ * merged:
+ *
+ * [ prev ][ vma ][ next ]
+ *
+ * In no case will we need to delete prev. If the operation is
+ * mergeable, then prev will be extended with one or both of vma and
+ * next deleted.
+ *
+ * As a result, during initial mergeability checks, only
+ * can_vma_merge_before() (which implies the VMA being merged with is
+ * 'next' as shown above) bothers to check to see whether the next VMA
+ * has a vm_ops->close() callback that will need to be called when
+ * removed.
+ *
+ * If it does, then we cannot merge as the resources that the close()
+ * operation potentially clears down are tied only to the existing VMA
+ * range and we have no way of extending those to the nearly merged one.
+ *
+ * We must consider two scenarios:
+ *
+ * A.
+ *
+ * vm_ops->close: - - !NULL
+ * [ prev ][ vma ][ next ]
+ *
+ * Where prev may or may not be present/mergeable.
+ *
+ * This is picked up by a specific check in can_vma_merge_before().
+ *
+ * B.
+ *
+ * vm_ops->close: - !NULL
+ * [ prev ][ vma ]
+ *
+ * Where prev and vma are present and mergeable.
+ *
+ * This is picked up by a specific check in the modified VMA merge.
+ *
+ * IMPORTANT NOTE: We make the assumption that the following case:
+ *
+ * - !NULL NULL
+ * [ prev ][ vma ][ next ]
+ *
+ * Cannot occur, because vma->vm_ops being the same implies the same
+ * vma->vm_file, and therefore this would mean that next->vm_ops->close
+ * would be set too, and thus scenario A would pick this up.
+ */
+
+ /*
+ * The only case of a new VMA merge that results in a VMA being deleted
+ * is one where both the previous and next VMAs are merged - in this
+ * instance the next VMA is deleted, and the previous VMA is extended.
+ *
+ * If we are unable to do so, we reduce the operation to simply
+ * extending the prev VMA and not merging next.
+ *
+ * 0123456789
+ * PPP**NNNN
+ * ->
+ * 0123456789
+ * PPPPPPNNN
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x9000, 5, flags);
+ vma_next->vm_ops = &vm_ops;
+
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ ASSERT_EQ(merge_new(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x5000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ /*
+ * When modifying an existing VMA there are further cases where we
+ * delete VMAs.
+ *
+ * <>
+ * 0123456789
+ * PPPVV
+ *
+ * In this instance, if vma has a close hook, the merge simply cannot
+ * proceed.
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma->vm_ops = &vm_ops;
+
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ /*
+ * The VMA being modified in a way that would otherwise merge should
+ * also fail.
+ */
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ /*
+ * This case is mirrored if merging with next.
+ *
+ * <>
+ * 0123456789
+ * VVNNNN
+ *
+ * In this instance, if vma has a close hook, the merge simply cannot
+ * proceed.
+ */
+
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x9000, 5, flags);
+ vma->vm_ops = &vm_ops;
+
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ /*
+ * Initially this is misapprehended as an out of memory report, as the
+ * close() check is handled in the same way as anon_vma duplication
+ * failures, however a subsequent patch resolves this.
+ */
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ /*
+ * Finally, we consider two variants of the case where we modify a VMA
+ * to merge with both the previous and next VMAs.
+ *
+ * The first variant is where vma has a close hook. In this instance, no
+ * merge can proceed.
+ *
+ * <>
+ * 0123456789
+ * PPPVVNNNN
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x9000, 5, flags);
+ vma->vm_ops = &vm_ops;
+
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 3);
+
+ /*
+ * The second variant is where next has a close hook. In this instance,
+ * we reduce the operation to a merge between prev and vma.
+ *
+ * <>
+ * 0123456789
+ * PPPVVNNNN
+ * ->
+ * 0123456789
+ * PPPPPNNNN
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x9000, 5, flags);
+ vma_next->vm_ops = &vm_ops;
+
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x5000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ return true;
+}
+
+static bool test_vma_merge_new_with_close(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ struct vm_area_struct *vma_prev = alloc_and_link_vma(&mm, 0, 0x2000, 0, flags);
+ struct vm_area_struct *vma_next = alloc_and_link_vma(&mm, 0x5000, 0x7000, 5, flags);
+ const struct vm_operations_struct vm_ops = {
+ .close = dummy_close,
+ };
+ struct vm_area_struct *vma;
+
+ /*
+ * We should allow the partial merge of a proposed new VMA if the
+ * surrounding VMAs have vm_ops->close() hooks (but are otherwise
+ * compatible), e.g.:
+ *
+ * New VMA
+ * A v-------v B
+ * |-----| |-----|
+ * close close
+ *
+ * Since the rule is to not DELETE a VMA with a close operation, this
+ * should be permitted, only rather than expanding A and deleting B, we
+ * should simply expand A and leave B intact, e.g.:
+ *
+ * New VMA
+ * A B
+ * |------------||-----|
+ * close close
+ */
+
+ /* Have prev and next have a vm_ops->close() hook. */
+ vma_prev->vm_ops = &vm_ops;
+ vma_next->vm_ops = &vm_ops;
+
+ vmg_set_range(&vmg, 0x2000, 0x5000, 2, flags);
+ vma = merge_new(&vmg);
+ ASSERT_NE(vma, NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x5000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_EQ(vma->vm_ops, &vm_ops);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 2);
+
+ cleanup_mm(&mm, &vmi);
+ return true;
+}
+
+static bool test_merge_existing(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vm_area_struct *vma, *vma_prev, *vma_next;
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ const struct vm_operations_struct vm_ops = {
+ .close = dummy_close,
+ };
+
+ /*
+ * Merge right case - partial span.
+ *
+ * <->
+ * 0123456789
+ * VVVVNNN
+ * ->
+ * 0123456789
+ * VNNNNNN
+ */
+ vma = alloc_and_link_vma(&mm, 0x2000, 0x6000, 2, flags);
+ vma->vm_ops = &vm_ops; /* This should have no impact. */
+ vma_next = alloc_and_link_vma(&mm, 0x6000, 0x9000, 6, flags);
+ vma_next->vm_ops = &vm_ops; /* This should have no impact. */
+ vmg_set_range(&vmg, 0x3000, 0x6000, 3, flags);
+ vmg.vma = vma;
+ vmg.prev = vma;
+ vma->anon_vma = &dummy_anon_vma;
+ ASSERT_EQ(merge_existing(&vmg), vma_next);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_next->vm_start, 0x3000);
+ ASSERT_EQ(vma_next->vm_end, 0x9000);
+ ASSERT_EQ(vma_next->vm_pgoff, 3);
+ ASSERT_EQ(vma_next->anon_vma, &dummy_anon_vma);
+ ASSERT_EQ(vma->vm_start, 0x2000);
+ ASSERT_EQ(vma->vm_end, 0x3000);
+ ASSERT_EQ(vma->vm_pgoff, 2);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_TRUE(vma_write_started(vma_next));
+ ASSERT_EQ(mm.map_count, 2);
+
+ /* Clear down and reset. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ /*
+ * Merge right case - full span.
+ *
+ * <-->
+ * 0123456789
+ * VVVVNNN
+ * ->
+ * 0123456789
+ * NNNNNNN
+ */
+ vma = alloc_and_link_vma(&mm, 0x2000, 0x6000, 2, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x6000, 0x9000, 6, flags);
+ vma_next->vm_ops = &vm_ops; /* This should have no impact. */
+ vmg_set_range(&vmg, 0x2000, 0x6000, 2, flags);
+ vmg.vma = vma;
+ vma->anon_vma = &dummy_anon_vma;
+ ASSERT_EQ(merge_existing(&vmg), vma_next);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_next->vm_start, 0x2000);
+ ASSERT_EQ(vma_next->vm_end, 0x9000);
+ ASSERT_EQ(vma_next->vm_pgoff, 2);
+ ASSERT_EQ(vma_next->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma_next));
+ ASSERT_EQ(mm.map_count, 1);
+
+ /* Clear down and reset. We should have deleted vma. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 1);
+
+ /*
+ * Merge left case - partial span.
+ *
+ * <->
+ * 0123456789
+ * PPPVVVV
+ * ->
+ * 0123456789
+ * PPPPPPV
+ */
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma_prev->vm_ops = &vm_ops; /* This should have no impact. */
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, flags);
+ vma->vm_ops = &vm_ops; /* This should have no impact. */
+ vmg_set_range(&vmg, 0x3000, 0x6000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+ vma->anon_vma = &dummy_anon_vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x6000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_EQ(vma->vm_start, 0x6000);
+ ASSERT_EQ(vma->vm_end, 0x7000);
+ ASSERT_EQ(vma->vm_pgoff, 6);
+ ASSERT_TRUE(vma_write_started(vma_prev));
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 2);
+
+ /* Clear down and reset. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ /*
+ * Merge left case - full span.
+ *
+ * <-->
+ * 0123456789
+ * PPPVVVV
+ * ->
+ * 0123456789
+ * PPPPPPP
+ */
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma_prev->vm_ops = &vm_ops; /* This should have no impact. */
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, flags);
+ vmg_set_range(&vmg, 0x3000, 0x7000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+ vma->anon_vma = &dummy_anon_vma;
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x7000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma_prev));
+ ASSERT_EQ(mm.map_count, 1);
+
+ /* Clear down and reset. We should have deleted vma. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 1);
+
+ /*
+ * Merge both case.
+ *
+ * <-->
+ * 0123456789
+ * PPPVVVVNNN
+ * ->
+ * 0123456789
+ * PPPPPPPPPP
+ */
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma_prev->vm_ops = &vm_ops; /* This should have no impact. */
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x7000, 0x9000, 7, flags);
+ vmg_set_range(&vmg, 0x3000, 0x7000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+ vma->anon_vma = &dummy_anon_vma;
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x9000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_write_started(vma_prev));
+ ASSERT_EQ(mm.map_count, 1);
+
+ /* Clear down and reset. We should have deleted prev and next. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 1);
+
+ /*
+ * Non-merge ranges. the modified VMA merge operation assumes that the
+ * caller always specifies ranges within the input VMA so we need only
+ * examine these cases.
+ *
+ * -
+ * -
+ * -
+ * <->
+ * <>
+ * <>
+ * 0123456789a
+ * PPPVVVVVNNN
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x8000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x8000, 0xa000, 8, flags);
+
+ vmg_set_range(&vmg, 0x4000, 0x5000, 4, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ vmg_set_range(&vmg, 0x5000, 0x6000, 5, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ vmg_set_range(&vmg, 0x6000, 0x7000, 6, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ vmg_set_range(&vmg, 0x4000, 0x7000, 4, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ vmg_set_range(&vmg, 0x4000, 0x6000, 4, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ vmg_set_range(&vmg, 0x5000, 0x6000, 5, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_NOMERGE);
+
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 3);
+
+ return true;
+}
+
+static bool test_anon_vma_non_mergeable(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vm_area_struct *vma, *vma_prev, *vma_next;
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain1 = {
+ .anon_vma = &dummy_anon_vma,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain2 = {
+ .anon_vma = &dummy_anon_vma,
+ };
+
+ /*
+ * In the case of modified VMA merge, merging both left and right VMAs
+ * but where prev and next have incompatible anon_vma objects, we revert
+ * to a merge of prev and VMA:
+ *
+ * <-->
+ * 0123456789
+ * PPPVVVVNNN
+ * ->
+ * 0123456789
+ * PPPPPPPNNN
+ */
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x7000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x7000, 0x9000, 7, flags);
+
+ /*
+ * Give both prev and next single anon_vma_chain fields, so they will
+ * merge with the NULL vmg->anon_vma.
+ *
+ * However, when prev is compared to next, the merge should fail.
+ */
+
+ INIT_LIST_HEAD(&vma_prev->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain1.same_vma, &vma_prev->anon_vma_chain);
+ ASSERT_TRUE(list_is_singular(&vma_prev->anon_vma_chain));
+ vma_prev->anon_vma = &dummy_anon_vma;
+ ASSERT_TRUE(is_mergeable_anon_vma(NULL, vma_prev->anon_vma, vma_prev));
+
+ INIT_LIST_HEAD(&vma_next->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain2.same_vma, &vma_next->anon_vma_chain);
+ ASSERT_TRUE(list_is_singular(&vma_next->anon_vma_chain));
+ vma_next->anon_vma = (struct anon_vma *)2;
+ ASSERT_TRUE(is_mergeable_anon_vma(NULL, vma_next->anon_vma, vma_next));
+
+ ASSERT_FALSE(is_mergeable_anon_vma(vma_prev->anon_vma, vma_next->anon_vma, NULL));
+
+ vmg_set_range(&vmg, 0x3000, 0x7000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x7000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+ ASSERT_TRUE(vma_write_started(vma_prev));
+ ASSERT_FALSE(vma_write_started(vma_next));
+
+ /* Clear down and reset. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ /*
+ * Now consider the new VMA case. This is equivalent, only adding a new
+ * VMA in a gap between prev and next.
+ *
+ * <-->
+ * 0123456789
+ * PPP****NNN
+ * ->
+ * 0123456789
+ * PPPPPPPNNN
+ */
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x7000, 0x9000, 7, flags);
+
+ INIT_LIST_HEAD(&vma_prev->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain1.same_vma, &vma_prev->anon_vma_chain);
+ vma_prev->anon_vma = (struct anon_vma *)1;
+
+ INIT_LIST_HEAD(&vma_next->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain2.same_vma, &vma_next->anon_vma_chain);
+ vma_next->anon_vma = (struct anon_vma *)2;
+
+ vmg_set_range(&vmg, 0x3000, 0x7000, 3, flags);
+ vmg.prev = vma_prev;
+
+ ASSERT_EQ(merge_new(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x7000);
+ ASSERT_EQ(vma_prev->vm_pgoff, 0);
+ ASSERT_TRUE(vma_write_started(vma_prev));
+ ASSERT_FALSE(vma_write_started(vma_next));
+
+ /* Final cleanup. */
+ ASSERT_EQ(cleanup_mm(&mm, &vmi), 2);
+
+ return true;
+}
+
+static bool test_dup_anon_vma(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ struct anon_vma_chain dummy_anon_vma_chain = {
+ .anon_vma = &dummy_anon_vma,
+ };
+ struct vm_area_struct *vma_prev, *vma_next, *vma;
+
+ reset_dummy_anon_vma();
+
+ /*
+ * Expanding a VMA delete the next one duplicates next's anon_vma and
+ * assigns it to the expanded VMA.
+ *
+ * This covers new VMA merging, as these operations amount to a VMA
+ * expand.
+ */
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_next->anon_vma = &dummy_anon_vma;
+
+ vmg_set_range(&vmg, 0, 0x5000, 0, flags);
+ vmg.vma = vma_prev;
+ vmg.next = vma_next;
+
+ ASSERT_EQ(expand_existing(&vmg), 0);
+
+ /* Will have been cloned. */
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_prev->anon_vma->was_cloned);
+
+ /* Cleanup ready for next run. */
+ cleanup_mm(&mm, &vmi);
+
+ /*
+ * next has anon_vma, we assign to prev.
+ *
+ * |<----->|
+ * |-------*********-------|
+ * prev vma next
+ * extend delete delete
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x8000, 5, flags);
+
+ /* Initialise avc so mergeability check passes. */
+ INIT_LIST_HEAD(&vma_next->anon_vma_chain);
+ list_add(&dummy_anon_vma_chain.same_vma, &vma_next->anon_vma_chain);
+
+ vma_next->anon_vma = &dummy_anon_vma;
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x8000);
+
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_prev->anon_vma->was_cloned);
+
+ cleanup_mm(&mm, &vmi);
+
+ /*
+ * vma has anon_vma, we assign to prev.
+ *
+ * |<----->|
+ * |-------*********-------|
+ * prev vma next
+ * extend delete delete
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x8000, 5, flags);
+
+ vma->anon_vma = &dummy_anon_vma;
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x8000);
+
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_prev->anon_vma->was_cloned);
+
+ cleanup_mm(&mm, &vmi);
+
+ /*
+ * vma has anon_vma, we assign to prev.
+ *
+ * |<----->|
+ * |-------*************
+ * prev vma
+ * extend shrink/delete
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x8000, 3, flags);
+
+ vma->anon_vma = &dummy_anon_vma;
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_prev);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+
+ ASSERT_EQ(vma_prev->vm_start, 0);
+ ASSERT_EQ(vma_prev->vm_end, 0x5000);
+
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_prev->anon_vma->was_cloned);
+
+ cleanup_mm(&mm, &vmi);
+
+ /*
+ * vma has anon_vma, we assign to next.
+ *
+ * |<----->|
+ * *************-------|
+ * vma next
+ * shrink/delete extend
+ */
+
+ vma = alloc_and_link_vma(&mm, 0, 0x5000, 0, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x5000, 0x8000, 5, flags);
+
+ vma->anon_vma = &dummy_anon_vma;
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma;
+ vmg.vma = vma;
+
+ ASSERT_EQ(merge_existing(&vmg), vma_next);
+ ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+
+ ASSERT_EQ(vma_next->vm_start, 0x3000);
+ ASSERT_EQ(vma_next->vm_end, 0x8000);
+
+ ASSERT_EQ(vma_next->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(vma_next->anon_vma->was_cloned);
+
+ cleanup_mm(&mm, &vmi);
+ return true;
+}
+
+static bool test_vmi_prealloc_fail(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vma_merge_struct vmg = {
+ .mm = &mm,
+ .vmi = &vmi,
+ };
+ struct vm_area_struct *vma_prev, *vma;
+
+ /*
+ * We are merging vma into prev, with vma possessing an anon_vma, which
+ * will be duplicated. We cause the vmi preallocation to fail and assert
+ * the duplicated anon_vma is unlinked.
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma->anon_vma = &dummy_anon_vma;
+
+ vmg_set_range(&vmg, 0x3000, 0x5000, 3, flags);
+ vmg.prev = vma_prev;
+ vmg.vma = vma;
+
+ fail_prealloc = true;
+
+ /* This will cause the merge to fail. */
+ ASSERT_EQ(merge_existing(&vmg), NULL);
+ ASSERT_EQ(vmg.state, VMA_MERGE_ERROR_NOMEM);
+ /* We will already have assigned the anon_vma. */
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ /* And it was both cloned and unlinked. */
+ ASSERT_TRUE(dummy_anon_vma.was_cloned);
+ ASSERT_TRUE(dummy_anon_vma.was_unlinked);
+
+ cleanup_mm(&mm, &vmi); /* Resets fail_prealloc too. */
+
+ /*
+ * We repeat the same operation for expanding a VMA, which is what new
+ * VMA merging ultimately uses too. This asserts that unlinking is
+ * performed in this case too.
+ */
+
+ vma_prev = alloc_and_link_vma(&mm, 0, 0x3000, 0, flags);
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma->anon_vma = &dummy_anon_vma;
+
+ vmg_set_range(&vmg, 0, 0x5000, 3, flags);
+ vmg.vma = vma_prev;
+ vmg.next = vma;
+
+ fail_prealloc = true;
+ ASSERT_EQ(expand_existing(&vmg), -ENOMEM);
+ ASSERT_EQ(vmg.state, VMA_MERGE_ERROR_NOMEM);
+
+ ASSERT_EQ(vma_prev->anon_vma, &dummy_anon_vma);
+ ASSERT_TRUE(dummy_anon_vma.was_cloned);
+ ASSERT_TRUE(dummy_anon_vma.was_unlinked);
+
+ cleanup_mm(&mm, &vmi);
+ return true;
+}
+
+static bool test_merge_extend(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ VMA_ITERATOR(vmi, &mm, 0x1000);
+ struct vm_area_struct *vma;
+
+ vma = alloc_and_link_vma(&mm, 0, 0x1000, 0, flags);
+ alloc_and_link_vma(&mm, 0x3000, 0x4000, 3, flags);
+
+ /*
+ * Extend a VMA into the gap between itself and the following VMA.
+ * This should result in a merge.
+ *
+ * <->
+ * * *
+ *
+ */
+
+ ASSERT_EQ(vma_merge_extend(&vmi, vma, 0x2000), vma);
+ ASSERT_EQ(vma->vm_start, 0);
+ ASSERT_EQ(vma->vm_end, 0x4000);
+ ASSERT_EQ(vma->vm_pgoff, 0);
+ ASSERT_TRUE(vma_write_started(vma));
+ ASSERT_EQ(mm.map_count, 1);
+
+ cleanup_mm(&mm, &vmi);
+ return true;
+}
+
+static bool test_copy_vma(void)
+{
+ unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+ struct mm_struct mm = {};
+ bool need_locks = false;
+ VMA_ITERATOR(vmi, &mm, 0);
+ struct vm_area_struct *vma, *vma_new, *vma_next;
+
+ /* Move backwards and do not merge. */
+
+ vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+ vma_new = copy_vma(&vma, 0, 0x2000, 0, &need_locks);
+
+ ASSERT_NE(vma_new, vma);
+ ASSERT_EQ(vma_new->vm_start, 0);
+ ASSERT_EQ(vma_new->vm_end, 0x2000);
+ ASSERT_EQ(vma_new->vm_pgoff, 0);
+
+ cleanup_mm(&mm, &vmi);
+
+ /* Move a VMA into position next to another and merge the two. */
+
+ vma = alloc_and_link_vma(&mm, 0, 0x2000, 0, flags);
+ vma_next = alloc_and_link_vma(&mm, 0x6000, 0x8000, 6, flags);
+ vma_new = copy_vma(&vma, 0x4000, 0x2000, 4, &need_locks);
+
+ ASSERT_EQ(vma_new, vma_next);
+
+ cleanup_mm(&mm, &vmi);
+ return true;
+}
+
+int main(void)
+{
+ int num_tests = 0, num_fail = 0;
+
+ maple_tree_init();
+
+#define TEST(name) \
+ do { \
+ num_tests++; \
+ if (!test_##name()) { \
+ num_fail++; \
+ fprintf(stderr, "Test " #name " FAILED\n"); \
+ } \
+ } while (0)
+
+ /* Very simple tests to kick the tyres. */
+ TEST(simple_merge);
+ TEST(simple_modify);
+ TEST(simple_expand);
+ TEST(simple_shrink);
+
+ TEST(merge_new);
+ TEST(vma_merge_special_flags);
+ TEST(vma_merge_with_close);
+ TEST(vma_merge_new_with_close);
+ TEST(merge_existing);
+ TEST(anon_vma_non_mergeable);
+ TEST(dup_anon_vma);
+ TEST(vmi_prealloc_fail);
+ TEST(merge_extend);
+ TEST(copy_vma);
+
+#undef TEST
+
+ printf("%d tests run, %d passed, %d failed.\n",
+ num_tests, num_tests - num_fail, num_fail);
+
+ return num_fail == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 22:04:07 +0000