On Mon, Jul 14, 2025 at 11:53:14AM -0700, Tiffany Yang wrote:

The binder allocator selftest was only checking the last page of buffers that ended on a page boundary. Correct the page indexing to account for buffers that are not page-aligned.

Signed-off-by: Tiffany Yang ynaffit@google.com

drivers/android/binder_alloc_selftest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/android/binder_alloc_selftest.c b/drivers/android/binder_alloc_selftest.c index c88735c54848..486af3ec3c02 100644 --- a/drivers/android/binder_alloc_selftest.c +++ b/drivers/android/binder_alloc_selftest.c @@ -142,12 +142,12 @@ static void binder_selftest_free_buf(struct binder_alloc *alloc, for (i = 0; i < BUFFER_NUM; i++) binder_alloc_free_buf(alloc, buffers[seq[i]]);

• for (i = 0; i < end / PAGE_SIZE; i++) {
          /**
           * Error message on a free page can be false positive
           * if binder shrinker ran during binder_alloc_free_buf
           * calls above.
           */
  

• for (i = 0; i <= (end - 1) / PAGE_SIZE; i++) {
          if (list_empty(page_to_lru(alloc->pages[i]))) {
                  pr_err_size_seq(sizes, seq);
                  pr_err("expect lru but is %s at page index %d\n",
  

-- 2.50.0.727.gbf7dc18ff4-goog

LGTM!

Acked-by: Carlos Llamas cmllamas@google.com

Kees Cook kees@kernel.org writes:

On Mon, Jul 14, 2025 at 11:53:14AM -0700, Tiffany Yang wrote:

...

The binder allocator selftest was only checking the last page of buffers that ended on a page boundary. Correct the page indexing to account for buffers that are not page-aligned.

...

Signed-off-by: Tiffany Yang ynaffit@google.com

drivers/android/binder_alloc_selftest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

...

diff --git a/drivers/android/binder_alloc_selftest.c b/drivers/android/binder_alloc_selftest.c index c88735c54848..486af3ec3c02 100644 --- a/drivers/android/binder_alloc_selftest.c +++ b/drivers/android/binder_alloc_selftest.c @@ -142,12 +142,12 @@ static void binder_selftest_free_buf(struct binder_alloc *alloc, for (i = 0; i < BUFFER_NUM; i++) binder_alloc_free_buf(alloc, buffers[seq[i]]);

...

• for (i = 0; i < end / PAGE_SIZE; i++) { /**
  • Error message on a free page can be false positive
  • if binder shrinker ran during binder_alloc_free_buf
  • calls above.
  */

• for (i = 0; i <= (end - 1) / PAGE_SIZE; i++) {

Nit: this comment is now not aligned correctly. Probably the best would be the leave the "for" line above the comment.

-Kees

Thank you for catching this! Will be fixed in v4.

...

if (list_empty(page_to_lru(alloc->pages[i]))) {
	pr_err_size_seq(sizes, seq);
	pr_err("expect lru but is %s at page index %d\n",

-- 2.50.0.727.gbf7dc18ff4-goog

Kees Cook kees@kernel.org writes:

...

• /**
  

•  * Error message on a free page can be false positive
  

•  * if binder shrinker ran during binder_alloc_free_buf
  

•  * calls above.
  

•  */
  

  for (i = 0; i <= (end - 1) / PAGE_SIZE; i++) { if (list_empty(page_to_lru(alloc->pages[i]))) { pr_err_size_seq(sizes, seq);

Ah, I see the comment is removed entirely here. Better to move this hunk to patch 1, then.

This comment is actually "true" until we allow a test-specific freelist in this change, but I've moved the "for" line back to where it was in the previous change. Thanks for noting this!

...

@@ -162,8 +159,8 @@ static void binder_selftest_free_page(struct binder_alloc *alloc) int i; unsigned long count;

...

• while ((count = list_lru_count(&binder_freelist))) {

• list_lru_walk(&binder_freelist, binder_alloc_free_page,
  

• while ((count = list_lru_count(&binder_selftest_freelist))) {

• list_lru_walk(&binder_selftest_freelist, binder_alloc_free_page,
        NULL, count);
  

  }

...

@@ -187,7 +184,7 @@ static void binder_selftest_alloc_free(struct binder_alloc *alloc,

...

/* Allocate from lru. */ binder_selftest_alloc_buf(alloc, buffers, sizes, seq);

• if (list_lru_count(&binder_freelist))

• if (list_lru_count(&binder_selftest_freelist)) pr_err("lru list should be empty but is not\n");

...

binder_selftest_free_buf(alloc, buffers, sizes, seq, end); @@ -275,6 +272,20 @@ static void binder_selftest_alloc_offset(struct binder_alloc *alloc, } }

...

+int binder_selftest_alloc_get_page_count(struct binder_alloc *alloc) +{

• struct page *page;
• int allocated = 0;
• int i;
• for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {

• page = alloc->pages[i];
  

• if (page)
  

• 	allocated++;
  

• }
• return allocated;

+}

• /**
  • binder_selftest_alloc() - Test alloc and free of buffer pages.
  • @alloc: Pointer to alloc struct.

@@ -286,6 +297,7 @@ static void binder_selftest_alloc_offset(struct binder_alloc *alloc, */ void binder_selftest_alloc(struct binder_alloc *alloc) {

• struct list_lru *prev_freelist; size_t end_offset[BUFFER_NUM];

...

if (!binder_selftest_run) @@ -293,14 +305,41 @@ void binder_selftest_alloc(struct binder_alloc *alloc) mutex_lock(&binder_selftest_lock); if (!binder_selftest_run || !alloc->mapped) goto done;

• prev_freelist = alloc->freelist;
• /*

• * It is not safe to modify this process's alloc->freelist if it has  
  

any

• * pages on a freelist. Since the test runs before any binder ioctls  
  

can

• * be dealt with, none of its pages should be allocated yet.
  

• */
  

• if (binder_selftest_alloc_get_page_count(alloc)) {

• pr_err("process has existing alloc state\n");
  

• goto cleanup;
  

• }
• if (list_lru_init(&binder_selftest_freelist)) {

• pr_err("failed to init test freelist\n");
  

• goto cleanup;
  

• }
• alloc->freelist = &binder_selftest_freelist;
• pr_info("STARTED\n"); binder_selftest_alloc_offset(alloc, end_offset, 0);

• binder_selftest_run = false; if (binder_selftest_failures > 0) pr_info("%d tests FAILED\n", binder_selftest_failures); else pr_info("PASSED\n");

...

• if (list_lru_count(&binder_selftest_freelist))

• pr_err("expect test freelist to be empty\n");
  

+cleanup:

• /* Even if we didn't run the test, it's no longer thread-safe. */
• binder_selftest_run = false;
• alloc->freelist = prev_freelist;
• list_lru_destroy(&binder_selftest_freelist); done: mutex_unlock(&binder_selftest_lock); }

-- 2.50.0.727.gbf7dc18ff4-goog

Otherwise looks good.

On Mon, Jul 14, 2025 at 11:53:16AM -0700, Tiffany Yang wrote:

Tests can allocate from virtual memory using kunit_vm_mmap(), which transparently creates and attaches an mm_struct to the test runner if one is not already attached. This is suitable for most cases, except for when the code under test must access a task's mm before performing an mmap. Expose kunit_attach_mm() as part of the interface for those cases. This does not change the existing behavior.

Cc: David Gow davidgow@google.com Signed-off-by: Tiffany Yang ynaffit@google.com

---

include/kunit/test.h | 12 ++++++++++++ lib/kunit/user_alloc.c | 4 ++-- 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h index 39c768f87dc9..d958ee53050e 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -531,6 +531,18 @@ static inline char *kunit_kstrdup(struct kunit *test, const char *str, gfp_t gfp */ const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp);

+/**

• • kunit_attach_mm() - Create and attach a new mm if it doesn't already exist.
• • Allocates a &struct mm_struct and attaches it to @current. In most cases, call
• • kunit_vm_mmap() without calling kunit_attach_mm() directly. Only necessary when
• • code under test accesses the mm before executing the mmap (e.g., to perform
• • additional initialization beforehand).
• • Return: 0 on success, -errno on failure.
• */

+int kunit_attach_mm(void);

/**

• kunit_vm_mmap() - Allocate KUnit-tracked vm_mmap() area
• @test: The test context object.

diff --git a/lib/kunit/user_alloc.c b/lib/kunit/user_alloc.c index 46951be018be..b8cac765e620 100644 --- a/lib/kunit/user_alloc.c +++ b/lib/kunit/user_alloc.c @@ -22,8 +22,7 @@ struct kunit_vm_mmap_params { unsigned long offset; };

-/* Create and attach a new mm if it doesn't already exist. */ -static int kunit_attach_mm(void) +int kunit_attach_mm(void) { struct mm_struct *mm;

@@ -49,6 +48,7 @@ static int kunit_attach_mm(void)

  return 0;

} +EXPORT_SYMBOL_GPL(kunit_attach_mm);

static int kunit_vm_mmap_init(struct kunit_resource *res, void *context) { -- 2.50.0.727.gbf7dc18ff4-goog

LGTM!

Reviewed-by: Carlos Llamas cmllamas@google.com

Carlos Llamas cmllamas@google.com writes:

On Mon, Jul 14, 2025 at 11:53:17AM -0700, Tiffany Yang wrote:

...

Add setup and teardown for testing binder allocator code with KUnit. Include minimal test cases to verify that tests are initialized correctly.

...

Tested-by: Rae Moar rmoar@google.com Signed-off-by: Tiffany Yang ynaffit@google.com

---

v2:

• Added tested-by tag

v3:

• Split kunit lib change into separate change

---

drivers/android/Kconfig | 11 ++ drivers/android/Makefile | 1 + drivers/android/binder.c | 5 +- drivers/android/binder_alloc.c | 15 +- drivers/android/binder_alloc.h | 6 + drivers/android/binder_internal.h | 4 + drivers/android/tests/.kunitconfig | 3 + drivers/android/tests/Makefile | 3 + drivers/android/tests/binder_alloc_kunit.c | 166 +++++++++++++++++++++ 9 files changed, 208 insertions(+), 6 deletions(-) create mode 100644 drivers/android/tests/.kunitconfig create mode 100644 drivers/android/tests/Makefile create mode 100644 drivers/android/tests/binder_alloc_kunit.c

...

diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig index 07aa8ae0a058..b1bc7183366c 100644 --- a/drivers/android/Kconfig +++ b/drivers/android/Kconfig @@ -47,4 +47,15 @@ config ANDROID_BINDER_IPC_SELFTEST exhaustively with combinations of various buffer sizes and alignments.

...

+config ANDROID_BINDER_ALLOC_KUNIT_TEST

I think is OK to have "alloc" in the name. However, this is probably going to grow into just "binder" at some point (hopefully). Then we can just rename the kunit config as such.

My original thinking was that it would be nice to have multiple configs for various binder tests (i.e., if we wanted to have binderfs unit tests and other binder driver unit tests), but upon reflection, I'm not sure what purpose that would serve... I'll leave the "alloc" in it for now, but I agree we'll probably remove it for the future binder kunit tests.

...

• tristate "KUnit Tests for Android Binder Alloc" if !KUNIT_ALL_TESTS
  

• depends on ANDROID_BINDER_IPC && KUNIT
  

• default KUNIT_ALL_TESTS
  

• help
  

•   This feature builds the binder alloc KUnit tests.
  

•   Each test case runs using a pared-down binder_alloc struct and
  

•   test-specific freelist, which allows this KUnit module to be  
  

loaded

•   for testing without interfering with a running system.
  

• endmenu

diff --git a/drivers/android/Makefile b/drivers/android/Makefile index c9d3d0c99c25..74d02a335d4e 100644 --- a/drivers/android/Makefile +++ b/drivers/android/Makefile @@ -4,3 +4,4 @@ ccflags-y += -I$(src) # needed for trace events obj-$(CONFIG_ANDROID_BINDERFS) += binderfs.o obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o obj-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o +obj-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST) += tests/ diff --git a/drivers/android/binder.c b/drivers/android/binder.c index c463ca4a8fff..9dfe90c284fc 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -68,6 +68,8 @@ #include <linux/sizes.h> #include <linux/ktime.h>

...

+#include <kunit/visibility.h>

• #include <uapi/linux/android/binder.h>

...

#include <linux/cacheflush.h> @@ -5956,10 +5958,11 @@ static void binder_vma_close(struct vm_area_struct *vma) binder_alloc_vma_close(&proc->alloc); }

...

-static vm_fault_t binder_vm_fault(struct vm_fault *vmf) +VISIBLE_IF_KUNIT vm_fault_t binder_vm_fault(struct vm_fault *vmf) { return VM_FAULT_SIGBUS; } +EXPORT_SYMBOL_IF_KUNIT(binder_vm_fault);

...

static const struct vm_operations_struct binder_vm_ops = { .open = binder_vma_open, diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 2e89f9127883..c79e5c6721f0 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -23,6 +23,7 @@ #include <linux/uaccess.h> #include <linux/highmem.h> #include <linux/sizes.h> +#include <kunit/visibility.h> #include "binder_alloc.h" #include "binder_trace.h"

...

@@ -57,13 +58,14 @@ static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer) return list_entry(buffer->entry.prev, struct binder_buffer, entry); }

...

-static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,

•                                struct binder_buffer *buffer)
  

+VISIBLE_IF_KUNIT size_t binder_alloc_buffer_size(struct binder_alloc *alloc,

•                                          struct binder_buffer  
  

*buffer) { if (list_is_last(&buffer->entry, &alloc->buffers)) return alloc->vm_start + alloc->buffer_size - buffer->user_data; return binder_buffer_next(buffer)->user_data - buffer->user_data; } +EXPORT_SYMBOL_IF_KUNIT(binder_alloc_buffer_size);

...

static void binder_insert_free_buffer(struct binder_alloc *alloc, struct binder_buffer *new_buffer) @@ -959,7 +961,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc, failure_string, ret); return ret; }

+EXPORT_SYMBOL_IF_KUNIT(binder_alloc_mmap_handler);

...

void binder_alloc_deferred_release(struct binder_alloc *alloc) { @@ -1028,6 +1030,7 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc) "%s: %d buffers %d, pages %d\n", __func__, alloc->pid, buffers, page_count); } +EXPORT_SYMBOL_IF_KUNIT(binder_alloc_deferred_release);

...

/**

• binder_alloc_print_allocated() - print buffer info

@@ -1122,6 +1125,7 @@ void binder_alloc_vma_close(struct binder_alloc *alloc) { binder_alloc_set_mapped(alloc, false); } +EXPORT_SYMBOL_IF_KUNIT(binder_alloc_vma_close);

...

/**

• binder_alloc_free_page() - shrinker callback to free pages

@@ -1229,8 +1233,8 @@ binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)

...

static struct shrinker *binder_shrinker;

...

-static void __binder_alloc_init(struct binder_alloc *alloc,

•                         struct list_lru *freelist)
  

+VISIBLE_IF_KUNIT void __binder_alloc_init(struct binder_alloc *alloc,

•                                   struct list_lru *freelist)
  

  { alloc->pid = current->group_leader->pid; alloc->mm = current->mm;

@@ -1239,6 +1243,7 @@ static void __binder_alloc_init(struct binder_alloc *alloc, INIT_LIST_HEAD(&alloc->buffers); alloc->freelist = freelist; } +EXPORT_SYMBOL_IF_KUNIT(__binder_alloc_init);

...

/**

• binder_alloc_init() - called by binder_open() for per-proc

initialization diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h index aa05a9df1360..dc8dce2469a7 100644 --- a/drivers/android/binder_alloc.h +++ b/drivers/android/binder_alloc.h @@ -188,5 +188,11 @@ int binder_alloc_copy_from_buffer(struct binder_alloc *alloc, binder_size_t buffer_offset, size_t bytes);

...

+#if IS_ENABLED(CONFIG_KUNIT) +void __binder_alloc_init(struct binder_alloc *alloc, struct list_lru *freelist); +size_t binder_alloc_buffer_size(struct binder_alloc *alloc,

•                         struct binder_buffer *buffer);
  

+#endif

• #endif /* _LINUX_BINDER_ALLOC_H */

...

diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h index 1ba5caf1d88d..b5d3014fb4dc 100644 --- a/drivers/android/binder_internal.h +++ b/drivers/android/binder_internal.h @@ -592,4 +592,8 @@ void binder_add_device(struct binder_device *device); */ void binder_remove_device(struct binder_device *device);

...

+#if IS_ENABLED(CONFIG_KUNIT) +vm_fault_t binder_vm_fault(struct vm_fault *vmf); +#endif

• #endif /* _LINUX_BINDER_INTERNAL_H */

diff --git a/drivers/android/tests/.kunitconfig b/drivers/android/tests/.kunitconfig new file mode 100644 index 000000000000..a73601231049 --- /dev/null +++ b/drivers/android/tests/.kunitconfig @@ -0,0 +1,3 @@ +CONFIG_KUNIT=y +CONFIG_ANDROID_BINDER_IPC=y +CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST=y diff --git a/drivers/android/tests/Makefile b/drivers/android/tests/Makefile new file mode 100644 index 000000000000..6780967e573b --- /dev/null +++ b/drivers/android/tests/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only

All the new files need the copyright notice. Something like: "Copyright 2025 Google LCC"

Done.

...

+obj-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST) += binder_alloc_kunit.o diff --git a/drivers/android/tests/binder_alloc_kunit.c b/drivers/android/tests/binder_alloc_kunit.c new file mode 100644 index 000000000000..4b68b5687d33 --- /dev/null +++ b/drivers/android/tests/binder_alloc_kunit.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Test cases for binder allocator code
• */

+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <kunit/test.h> +#include <linux/anon_inodes.h> +#include <linux/err.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/sizes.h>

+#include "../binder_alloc.h" +#include "../binder_internal.h"

+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");

+#define BINDER_MMAP_SIZE SZ_128K

+struct binder_alloc_test {

• struct binder_alloc alloc;
  

• struct list_lru binder_test_freelist;
  

• struct file *filp;
  

• unsigned long mmap_uaddr;
  

+};

+static void binder_alloc_test_init_freelist(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
  

• KUNIT_EXPECT_PTR_EQ(test, priv->alloc.freelist,
  

•                     &priv->binder_test_freelist);
  

+}

+static void binder_alloc_test_mmap(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
  

• struct binder_alloc *alloc = &priv->alloc;
  

• struct binder_buffer *buf;
  

• struct rb_node *n;
  

• KUNIT_EXPECT_EQ(test, alloc->mapped, true);
  

• KUNIT_EXPECT_EQ(test, alloc->buffer_size, BINDER_MMAP_SIZE);
  

• n = rb_first(&alloc->allocated_buffers);
  

• KUNIT_EXPECT_PTR_EQ(test, n, NULL);
  

• n = rb_first(&alloc->free_buffers);
  

• buf = rb_entry(n, struct binder_buffer, rb_node);
  

• KUNIT_EXPECT_EQ(test, binder_alloc_buffer_size(alloc, buf),
  

•                 BINDER_MMAP_SIZE);
  

• KUNIT_EXPECT_TRUE(test, list_is_last(&buf->entry,  
  

&alloc->buffers)); +}

+/* ===== End test cases ===== */

+static void binder_alloc_test_vma_close(struct vm_area_struct *vma) +{

• struct binder_alloc *alloc = vma->vm_private_data;
  

• binder_alloc_vma_close(alloc);
  

+}

+static const struct vm_operations_struct binder_alloc_test_vm_ops = {

• .close = binder_alloc_test_vma_close,
  

• .fault = binder_vm_fault,
  

+};

+static int binder_alloc_test_mmap_handler(struct file *filp,

•                                   struct vm_area_struct *vma)
  

+{

• struct binder_alloc *alloc = filp->private_data;
  

• vm_flags_mod(vma, VM_DONTCOPY | VM_MIXEDMAP, VM_MAYWRITE);
  

• vma->vm_ops = &binder_alloc_test_vm_ops;
  

• vma->vm_private_data = alloc;
  

• return binder_alloc_mmap_handler(alloc, vma);
  

+}

+static const struct file_operations binder_alloc_test_fops = {

• .mmap = binder_alloc_test_mmap_handler,
  

+};

+static int binder_alloc_test_init(struct kunit *test) +{

• struct binder_alloc_test *priv;
  

• int ret;
  

• priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
  

• if (!priv)
  

•         return -ENOMEM;
  

• test->priv = priv;
  

• ret = list_lru_init(&priv->binder_test_freelist);
  

• if (ret) {
  

•         kunit_err(test, "Failed to initialize test freelist\n");
  

•         return ret;
  

• }
  

• /* __binder_alloc_init requires mm to be attached */
  

• ret = kunit_attach_mm();
  

• if (ret) {
  

•         kunit_err(test, "Failed to attach mm\n");
  

•         return ret;
  

• }
  

• __binder_alloc_init(&priv->alloc, &priv->binder_test_freelist);
  

• priv->filp = anon_inode_getfile("binder_alloc_kunit",
  

•                                 &binder_alloc_test_fops,  
  

&priv->alloc,

•                                 O_RDWR | O_CLOEXEC);
  

• if (IS_ERR_OR_NULL(priv->filp)) {
  

•         kunit_err(test, "Failed to open binder alloc test driver  
  

file\n");

•         return priv->filp ? PTR_ERR(priv->filp) : -ENOMEM;
  

• }
  

• priv->mmap_uaddr = kunit_vm_mmap(test, priv->filp, 0,  
  

BINDER_MMAP_SIZE,

•                                  PROT_READ, MAP_PRIVATE |  
  

MAP_NORESERVE,

•                                  0);
  

• if (!priv->mmap_uaddr) {
  

•         kunit_err(test, "Could not map the test's transaction  
  

memory\n");

•         return -ENOMEM;
  

• }
  

• return 0;
  

+}

+static void binder_alloc_test_exit(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
  

• /* Close the backing file to make sure binder_alloc_vma_close runs  
  

*/

• if (!IS_ERR_OR_NULL(priv->filp))
  

•         fput(priv->filp);
  

• if (priv->alloc.mm)
  

•         binder_alloc_deferred_release(&priv->alloc);
  

• /* Make sure freelist is empty */
  

• KUNIT_EXPECT_EQ(test, list_lru_count(&priv->binder_test_freelist),  
  

0);

• list_lru_destroy(&priv->binder_test_freelist);
  

+}

+static struct kunit_case binder_alloc_test_cases[] = {

• KUNIT_CASE(binder_alloc_test_init_freelist),
  

• KUNIT_CASE(binder_alloc_test_mmap),
  

• {}
  

+};

+static struct kunit_suite binder_alloc_test_suite = {

• .name = "binder_alloc",
  

• .test_cases = binder_alloc_test_cases,
  

• .init = binder_alloc_test_init,
  

• .exit = binder_alloc_test_exit,
  

+};

+kunit_test_suite(binder_alloc_test_suite);

+MODULE_AUTHOR("Tiffany Yang ynaffit@google.com"); +MODULE_DESCRIPTION("Binder Alloc KUnit tests");

+MODULE_LICENSE("GPL");

2.50.0.727.gbf7dc18ff4-goog

Aside from the missing Copyright, feel free to add:

Acked-by: Carlos Llamas cmllamas@google.com

Thanks for the review!

Kees Cook kees@kernel.org writes:

...

...

I'm used to the "#ifdef CONFIG_..." idiom, but looking at the tree, I see that "#if IS_ENANLED(CONFIG...)" is relatively common too. I don't think there is a function difference, so I leave the style choice up to you! ;)

IIRC, I had tried using the #ifdef to inject test-specific code in some places, but that created issues when we were loading KUnit as a module because it causes the built-in code to be built as though the "CONFIG_..." is undefined. Consequently, I started using IS_ENABLED by default, but I'm not sure if it's strictly necessary for exposing functions with a header file since I'd assume "CONFIG_..." will be defined when we're building the module?

...

• #endif /* _LINUX_BINDER_INTERNAL_H */

diff --git a/drivers/android/tests/.kunitconfig b/drivers/android/tests/.kunitconfig new file mode 100644 index 000000000000..a73601231049 --- /dev/null +++ b/drivers/android/tests/.kunitconfig @@ -0,0 +1,3 @@ +CONFIG_KUNIT=y +CONFIG_ANDROID_BINDER_IPC=y +CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST=y diff --git a/drivers/android/tests/Makefile b/drivers/android/tests/Makefile new file mode 100644 index 000000000000..6780967e573b --- /dev/null +++ b/drivers/android/tests/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only

+obj-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST) += binder_alloc_kunit.o diff --git a/drivers/android/tests/binder_alloc_kunit.c b/drivers/android/tests/binder_alloc_kunit.c new file mode 100644 index 000000000000..4b68b5687d33 --- /dev/null +++ b/drivers/android/tests/binder_alloc_kunit.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Test cases for binder allocator code
• */

+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <kunit/test.h> +#include <linux/anon_inodes.h> +#include <linux/err.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/sizes.h>

+#include "../binder_alloc.h" +#include "../binder_internal.h"

+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");

+#define BINDER_MMAP_SIZE SZ_128K

+struct binder_alloc_test {

• struct binder_alloc alloc;
• struct list_lru binder_test_freelist;
• struct file *filp;
• unsigned long mmap_uaddr;

+};

+static void binder_alloc_test_init_freelist(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
• KUNIT_EXPECT_PTR_EQ(test, priv->alloc.freelist,

• 	    &priv->binder_test_freelist);
  

+}

+static void binder_alloc_test_mmap(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
• struct binder_alloc *alloc = &priv->alloc;
• struct binder_buffer *buf;
• struct rb_node *n;
• KUNIT_EXPECT_EQ(test, alloc->mapped, true);
• KUNIT_EXPECT_EQ(test, alloc->buffer_size, BINDER_MMAP_SIZE);
• n = rb_first(&alloc->allocated_buffers);
• KUNIT_EXPECT_PTR_EQ(test, n, NULL);
• n = rb_first(&alloc->free_buffers);
• buf = rb_entry(n, struct binder_buffer, rb_node);
• KUNIT_EXPECT_EQ(test, binder_alloc_buffer_size(alloc, buf),

• 	BINDER_MMAP_SIZE);
  

• KUNIT_EXPECT_TRUE(test, list_is_last(&buf->entry, &alloc->buffers));

+}

+/* ===== End test cases ===== */

+static void binder_alloc_test_vma_close(struct vm_area_struct *vma) +{

• struct binder_alloc *alloc = vma->vm_private_data;
• binder_alloc_vma_close(alloc);

+}

+static const struct vm_operations_struct binder_alloc_test_vm_ops = {

• .close = binder_alloc_test_vma_close,
• .fault = binder_vm_fault,

+};

+static int binder_alloc_test_mmap_handler(struct file *filp,

• 			  struct vm_area_struct *vma)
  

+{

• struct binder_alloc *alloc = filp->private_data;
• vm_flags_mod(vma, VM_DONTCOPY | VM_MIXEDMAP, VM_MAYWRITE);
• vma->vm_ops = &binder_alloc_test_vm_ops;
• vma->vm_private_data = alloc;
• return binder_alloc_mmap_handler(alloc, vma);

+}

+static const struct file_operations binder_alloc_test_fops = {

• .mmap = binder_alloc_test_mmap_handler,

+};

+static int binder_alloc_test_init(struct kunit *test) +{

• struct binder_alloc_test *priv;
• int ret;
• priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
• if (!priv)

• return -ENOMEM;
  

• test->priv = priv;
• ret = list_lru_init(&priv->binder_test_freelist);
• if (ret) {

• kunit_err(test, "Failed to initialize test freelist\n");
  

• return ret;
  

• }
• /* __binder_alloc_init requires mm to be attached */
• ret = kunit_attach_mm();
• if (ret) {

• kunit_err(test, "Failed to attach mm\n");
  

• return ret;
  

• }
• __binder_alloc_init(&priv->alloc, &priv->binder_test_freelist);
• priv->filp = anon_inode_getfile("binder_alloc_kunit",

• 			&binder_alloc_test_fops, &priv->alloc,
  

• 			O_RDWR | O_CLOEXEC);
  

• if (IS_ERR_OR_NULL(priv->filp)) {

• kunit_err(test, "Failed to open binder alloc test driver file\n");
  

• return priv->filp ? PTR_ERR(priv->filp) : -ENOMEM;
  

• }
• priv->mmap_uaddr = kunit_vm_mmap(test, priv->filp, 0, BINDER_MMAP_SIZE,

• 			 PROT_READ, MAP_PRIVATE | MAP_NORESERVE,
  

• 			 0);
  

• if (!priv->mmap_uaddr) {

• kunit_err(test, "Could not map the test's transaction memory\n");
  

• return -ENOMEM;
  

• }
• return 0;

+}

+static void binder_alloc_test_exit(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
• /* Close the backing file to make sure binder_alloc_vma_close runs */
• if (!IS_ERR_OR_NULL(priv->filp))

• fput(priv->filp);
  

• if (priv->alloc.mm)

• binder_alloc_deferred_release(&priv->alloc);
  

• /* Make sure freelist is empty */
• KUNIT_EXPECT_EQ(test, list_lru_count(&priv->binder_test_freelist), 0);
• list_lru_destroy(&priv->binder_test_freelist);

+}

+static struct kunit_case binder_alloc_test_cases[] = {

• KUNIT_CASE(binder_alloc_test_init_freelist),
• KUNIT_CASE(binder_alloc_test_mmap),
• {}

+};

+static struct kunit_suite binder_alloc_test_suite = {

• .name = "binder_alloc",
• .test_cases = binder_alloc_test_cases,
• .init = binder_alloc_test_init,
• .exit = binder_alloc_test_exit,

+};

+kunit_test_suite(binder_alloc_test_suite);

+MODULE_AUTHOR("Tiffany Yang ynaffit@google.com"); +MODULE_DESCRIPTION("Binder Alloc KUnit tests"); +MODULE_LICENSE("GPL");

Reviewed-by: Kees Cook kees@kernel.org

On Mon, Jul 14, 2025 at 11:53:18AM -0700, Tiffany Yang wrote:

Convert the existing binder_alloc_selftest tests into KUnit tests. These tests allocate and free an exhaustive combination of buffers with various sizes and alignments. This change allows them to be run without blocking or otherwise interfering with other processes in binder.

This test is refactored into more meaningful cases in the subsequent patch.

Signed-off-by: Tiffany Yang ynaffit@google.com

v2:

• Fix build warning Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202506281837.hReNHJjO-lkp@intel.com/

---

drivers/android/Kconfig | 10 - drivers/android/Makefile | 1 - drivers/android/binder.c | 5 - drivers/android/binder_alloc.c | 3 + drivers/android/binder_alloc.h | 5 - drivers/android/binder_alloc_selftest.c | 345 --------------------- drivers/android/tests/binder_alloc_kunit.c | 279 +++++++++++++++++ 7 files changed, 282 insertions(+), 366 deletions(-) delete mode 100644 drivers/android/binder_alloc_selftest.c

diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig index b1bc7183366c..5b3b8041f827 100644 --- a/drivers/android/Kconfig +++ b/drivers/android/Kconfig @@ -37,16 +37,6 @@ config ANDROID_BINDER_DEVICES created. Each binder device has its own context manager, and is therefore logically separated from the other devices.

-config ANDROID_BINDER_IPC_SELFTEST

• bool "Android Binder IPC Driver Selftest"
  

• depends on ANDROID_BINDER_IPC
  

• help
  

•   This feature allows binder selftest to run.
  

•   Binder selftest checks the allocation and free of binder buffers
  

•   exhaustively with combinations of various buffer sizes and
  

•   alignments.
  

config ANDROID_BINDER_ALLOC_KUNIT_TEST tristate "KUnit Tests for Android Binder Alloc" if !KUNIT_ALL_TESTS depends on ANDROID_BINDER_IPC && KUNIT diff --git a/drivers/android/Makefile b/drivers/android/Makefile index 74d02a335d4e..c5d47be0276c 100644 --- a/drivers/android/Makefile +++ b/drivers/android/Makefile @@ -3,5 +3,4 @@ ccflags-y += -I$(src) # needed for trace events

obj-$(CONFIG_ANDROID_BINDERFS) += binderfs.o obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o -obj-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o obj-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST) += tests/ diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 9dfe90c284fc..7b2653a5d59c 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -5718,11 +5718,6 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) struct binder_thread *thread; void __user *ubuf = (void __user *)arg;

• /*pr_info("binder_ioctl: %d:%d %x %lx\n",
  

•                 proc->pid, current->pid, cmd, arg);*/
  

Thanks, this had been bothering me for a while.

• binder_selftest_alloc(&proc->alloc);
  

• trace_binder_ioctl(cmd, arg);
  
  ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
  

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index c79e5c6721f0..74a184014fa7 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -701,6 +701,7 @@ struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc, out: return buffer; } +EXPORT_SYMBOL_IF_KUNIT(binder_alloc_new_buf);

static unsigned long buffer_start_page(struct binder_buffer *buffer) { @@ -879,6 +880,7 @@ void binder_alloc_free_buf(struct binder_alloc *alloc, binder_free_buf_locked(alloc, buffer); mutex_unlock(&alloc->mutex); } +EXPORT_SYMBOL_IF_KUNIT(binder_alloc_free_buf);

/**

• binder_alloc_mmap_handler() - map virtual address space for proc

@@ -1217,6 +1219,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item, err_mmget: return LRU_SKIP; } +EXPORT_SYMBOL_IF_KUNIT(binder_alloc_free_page);

static unsigned long binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc) diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h index dc8dce2469a7..bed97c2cad92 100644 --- a/drivers/android/binder_alloc.h +++ b/drivers/android/binder_alloc.h @@ -121,11 +121,6 @@ struct binder_alloc { bool oneway_spam_detected; };

-#ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST -void binder_selftest_alloc(struct binder_alloc *alloc); -#else -static inline void binder_selftest_alloc(struct binder_alloc *alloc) {} -#endif enum lru_status binder_alloc_free_page(struct list_head *item, struct list_lru_one *lru, void *cb_arg); diff --git a/drivers/android/binder_alloc_selftest.c b/drivers/android/binder_alloc_selftest.c deleted file mode 100644 index 8b18b22aa3de..000000000000 --- a/drivers/android/binder_alloc_selftest.c +++ /dev/null @@ -1,345 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* binder_alloc_selftest.c

• • Android IPC Subsystem
• • Copyright (C) 2017 Google, Inc.
• */

-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

-#include <linux/err.h> -#include <linux/list_lru.h> -#include <linux/mm_types.h> -#include "binder_alloc.h"

-#define BUFFER_NUM 5 -#define BUFFER_MIN_SIZE (PAGE_SIZE / 8)

-static bool binder_selftest_run = true; -static int binder_selftest_failures; -static DEFINE_MUTEX(binder_selftest_lock); -static struct list_lru binder_selftest_freelist;

-/**

• • enum buf_end_align_type - Page alignment of a buffer
• • end with regard to the end of the previous buffer.
• • In the pictures below, buf2 refers to the buffer we
• • are aligning. buf1 refers to previous buffer by addr.
• • Symbol [ means the start of a buffer, ] means the end
• • of a buffer, and | means page boundaries.
• */

-enum buf_end_align_type {

• /**
  

•  * @SAME_PAGE_UNALIGNED: The end of this buffer is on
  

•  * the same page as the end of the previous buffer and
  

•  * is not page aligned. Examples:
  

•  * buf1 ][ buf2 ][ ...
  

•  * buf1 ]|[ buf2 ][ ...
  

•  */
  

• SAME_PAGE_UNALIGNED = 0,
  

• /**
  

•  * @SAME_PAGE_ALIGNED: When the end of the previous buffer
  

•  * is not page aligned, the end of this buffer is on the
  

•  * same page as the end of the previous buffer and is page
  

•  * aligned. When the previous buffer is page aligned, the
  

•  * end of this buffer is aligned to the next page boundary.
  

•  * Examples:
  

•  * buf1 ][ buf2 ]| ...
  

•  * buf1 ]|[ buf2 ]| ...
  

•  */
  

• SAME_PAGE_ALIGNED,
  

• /**
  

•  * @NEXT_PAGE_UNALIGNED: The end of this buffer is on
  

•  * the page next to the end of the previous buffer and
  

•  * is not page aligned. Examples:
  

•  * buf1 ][ buf2 | buf2 ][ ...
  

•  * buf1 ]|[ buf2 | buf2 ][ ...
  

•  */
  

• NEXT_PAGE_UNALIGNED,
  

• /**
  

•  * @NEXT_PAGE_ALIGNED: The end of this buffer is on
  

•  * the page next to the end of the previous buffer and
  

•  * is page aligned. Examples:
  

•  * buf1 ][ buf2 | buf2 ]| ...
  

•  * buf1 ]|[ buf2 | buf2 ]| ...
  

•  */
  

• NEXT_PAGE_ALIGNED,
  

• /**
  

•  * @NEXT_NEXT_UNALIGNED: The end of this buffer is on
  

•  * the page that follows the page after the end of the
  

•  * previous buffer and is not page aligned. Examples:
  

•  * buf1 ][ buf2 | buf2 | buf2 ][ ...
  

•  * buf1 ]|[ buf2 | buf2 | buf2 ][ ...
  

•  */
  

• NEXT_NEXT_UNALIGNED,
  

• /**
  

•  * @LOOP_END: The number of enum values in &buf_end_align_type.
  

•  * It is used for controlling loop termination.
  

•  */
  

• LOOP_END,
  

-};

-static void pr_err_size_seq(size_t *sizes, int *seq) -{

• int i;
  

• pr_err("alloc sizes: ");
  

• for (i = 0; i < BUFFER_NUM; i++)
  

•         pr_cont("[%zu]", sizes[i]);
  

• pr_cont("\n");
  

• pr_err("free seq: ");
  

• for (i = 0; i < BUFFER_NUM; i++)
  

•         pr_cont("[%d]", seq[i]);
  

• pr_cont("\n");
  

-}

-static bool check_buffer_pages_allocated(struct binder_alloc *alloc,

•                                  struct binder_buffer *buffer,
  

•                                  size_t size)
  

-{

• unsigned long page_addr;
  

• unsigned long end;
  

• int page_index;
  

• end = PAGE_ALIGN(buffer->user_data + size);
  

• page_addr = buffer->user_data;
  

• for (; page_addr < end; page_addr += PAGE_SIZE) {
  

•         page_index = (page_addr - alloc->vm_start) / PAGE_SIZE;
  

•         if (!alloc->pages[page_index] ||
  

•             !list_empty(page_to_lru(alloc->pages[page_index]))) {
  

•                 pr_err("expect alloc but is %s at page index %d\n",
  

•                        alloc->pages[page_index] ?
  

•                        "lru" : "free", page_index);
  

•                 return false;
  

•         }
  

• }
  

• return true;
  

-}

-static void binder_selftest_alloc_buf(struct binder_alloc *alloc,

•                               struct binder_buffer *buffers[],
  

•                               size_t *sizes, int *seq)
  

-{

• int i;
  

• for (i = 0; i < BUFFER_NUM; i++) {
  

•         buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0);
  

•         if (IS_ERR(buffers[i]) ||
  

•             !check_buffer_pages_allocated(alloc, buffers[i],
  

•                                           sizes[i])) {
  

•                 pr_err_size_seq(sizes, seq);
  

•                 binder_selftest_failures++;
  

•         }
  

• }
  

-}

-static void binder_selftest_free_buf(struct binder_alloc *alloc,

•                              struct binder_buffer *buffers[],
  

•                              size_t *sizes, int *seq, size_t end)
  

-{

• int i;
  

• for (i = 0; i < BUFFER_NUM; i++)
  

•         binder_alloc_free_buf(alloc, buffers[seq[i]]);
  

• for (i = 0; i <= (end - 1) / PAGE_SIZE; i++) {
  

•         if (list_empty(page_to_lru(alloc->pages[i]))) {
  

•                 pr_err_size_seq(sizes, seq);
  

•                 pr_err("expect lru but is %s at page index %d\n",
  

•                        alloc->pages[i] ? "alloc" : "free", i);
  

•                 binder_selftest_failures++;
  

•         }
  

• }
  

-}

-static void binder_selftest_free_page(struct binder_alloc *alloc) -{

• int i;
  

• unsigned long count;
  

• while ((count = list_lru_count(&binder_selftest_freelist))) {
  

•         list_lru_walk(&binder_selftest_freelist, binder_alloc_free_page,
  

•                       NULL, count);
  

• }
  

• for (i = 0; i < (alloc->buffer_size / PAGE_SIZE); i++) {
  

•         if (alloc->pages[i]) {
  

•                 pr_err("expect free but is %s at page index %d\n",
  

•                        list_empty(page_to_lru(alloc->pages[i])) ?
  

•                        "alloc" : "lru", i);
  

•                 binder_selftest_failures++;
  

•         }
  

• }
  

-}

-static void binder_selftest_alloc_free(struct binder_alloc *alloc,

•                                size_t *sizes, int *seq, size_t end)
  

-{

• struct binder_buffer *buffers[BUFFER_NUM];
  

• binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
  

• binder_selftest_free_buf(alloc, buffers, sizes, seq, end);
  

• /* Allocate from lru. */
  

• binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
  

• if (list_lru_count(&binder_selftest_freelist))
  

•         pr_err("lru list should be empty but is not\n");
  

• binder_selftest_free_buf(alloc, buffers, sizes, seq, end);
  

• binder_selftest_free_page(alloc);
  

-}

-static bool is_dup(int *seq, int index, int val) -{

• int i;
  

• for (i = 0; i < index; i++) {
  

•         if (seq[i] == val)
  

•                 return true;
  

• }
  

• return false;
  

-}

-/* Generate BUFFER_NUM factorial free orders. */ -static void binder_selftest_free_seq(struct binder_alloc *alloc,

•                              size_t *sizes, int *seq,
  

•                              int index, size_t end)
  

-{

• int i;
  

• if (index == BUFFER_NUM) {
  

•         binder_selftest_alloc_free(alloc, sizes, seq, end);
  

•         return;
  

• }
  

• for (i = 0; i < BUFFER_NUM; i++) {
  

•         if (is_dup(seq, index, i))
  

•                 continue;
  

•         seq[index] = i;
  

•         binder_selftest_free_seq(alloc, sizes, seq, index + 1, end);
  

• }
  

-}

-static void binder_selftest_alloc_size(struct binder_alloc *alloc,

•                                size_t *end_offset)
  

-{

• int i;
  

• int seq[BUFFER_NUM] = {0};
  

• size_t front_sizes[BUFFER_NUM];
  

• size_t back_sizes[BUFFER_NUM];
  

• size_t last_offset, offset = 0;
  

• for (i = 0; i < BUFFER_NUM; i++) {
  

•         last_offset = offset;
  

•         offset = end_offset[i];
  

•         front_sizes[i] = offset - last_offset;
  

•         back_sizes[BUFFER_NUM - i - 1] = front_sizes[i];
  

• }
  

• /*
  

•  * Buffers share the first or last few pages.
  

•  * Only BUFFER_NUM - 1 buffer sizes are adjustable since
  

•  * we need one giant buffer before getting to the last page.
  

•  */
  

• back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
  

• binder_selftest_free_seq(alloc, front_sizes, seq, 0,
  

•                          end_offset[BUFFER_NUM - 1]);
  

• binder_selftest_free_seq(alloc, back_sizes, seq, 0, alloc->buffer_size);
  

-}

-static void binder_selftest_alloc_offset(struct binder_alloc *alloc,

•                                  size_t *end_offset, int index)
  

-{

• int align;
  

• size_t end, prev;
  

• if (index == BUFFER_NUM) {
  

•         binder_selftest_alloc_size(alloc, end_offset);
  

•         return;
  

• }
  

• prev = index == 0 ? 0 : end_offset[index - 1];
  

• end = prev;
  

• BUILD_BUG_ON(BUFFER_MIN_SIZE * BUFFER_NUM >= PAGE_SIZE);
  

• for (align = SAME_PAGE_UNALIGNED; align < LOOP_END; align++) {
  

•         if (align % 2)
  

•                 end = ALIGN(end, PAGE_SIZE);
  

•         else
  

•                 end += BUFFER_MIN_SIZE;
  

•         end_offset[index] = end;
  

•         binder_selftest_alloc_offset(alloc, end_offset, index + 1);
  

• }
  

-}

-int binder_selftest_alloc_get_page_count(struct binder_alloc *alloc) -{

• struct page *page;
  

• int allocated = 0;
  

• int i;
  

• for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
  

•         page = alloc->pages[i];
  

•         if (page)
  

•                 allocated++;
  

• }
  

• return allocated;
  

-}

-/**

• • binder_selftest_alloc() - Test alloc and free of buffer pages.
• • @alloc: Pointer to alloc struct.
• • Allocate BUFFER_NUM buffers to cover all page alignment cases,
• • then free them in all orders possible. Check that pages are
• • correctly allocated, put onto lru when buffers are freed, and
• • are freed when binder_alloc_free_page is called.
• */

-void binder_selftest_alloc(struct binder_alloc *alloc) -{

• struct list_lru *prev_freelist;
  

• size_t end_offset[BUFFER_NUM];
  

• if (!binder_selftest_run)
  

•         return;
  

• mutex_lock(&binder_selftest_lock);
  

• if (!binder_selftest_run || !alloc->mapped)
  

•         goto done;
  

• prev_freelist = alloc->freelist;
  

• /*
  

•  * It is not safe to modify this process's alloc->freelist if it has any
  

•  * pages on a freelist. Since the test runs before any binder ioctls can
  

•  * be dealt with, none of its pages should be allocated yet.
  

•  */
  

• if (binder_selftest_alloc_get_page_count(alloc)) {
  

•         pr_err("process has existing alloc state\n");
  

•         goto cleanup;
  

• }
  

• if (list_lru_init(&binder_selftest_freelist)) {
  

•         pr_err("failed to init test freelist\n");
  

•         goto cleanup;
  

• }
  

• alloc->freelist = &binder_selftest_freelist;
  

• pr_info("STARTED\n");
  

• binder_selftest_alloc_offset(alloc, end_offset, 0);
  

• if (binder_selftest_failures > 0)
  

•         pr_info("%d tests FAILED\n", binder_selftest_failures);
  

• else
  

•         pr_info("PASSED\n");
  

• if (list_lru_count(&binder_selftest_freelist))
  

•         pr_err("expect test freelist to be empty\n");
  

-cleanup:

• /* Even if we didn't run the test, it's no longer thread-safe. */
  

• binder_selftest_run = false;
  

• alloc->freelist = prev_freelist;
  

• list_lru_destroy(&binder_selftest_freelist);
  

-done:

• mutex_unlock(&binder_selftest_lock);
  

-} diff --git a/drivers/android/tests/binder_alloc_kunit.c b/drivers/android/tests/binder_alloc_kunit.c index 4b68b5687d33..9e185e2036e5 100644 --- a/drivers/android/tests/binder_alloc_kunit.c +++ b/drivers/android/tests/binder_alloc_kunit.c @@ -21,6 +21,265 @@ MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");

#define BINDER_MMAP_SIZE SZ_128K

+#define BUFFER_NUM 5 +#define BUFFER_MIN_SIZE (PAGE_SIZE / 8)

+static int binder_alloc_test_failures;

+/**

• • enum buf_end_align_type - Page alignment of a buffer
• • end with regard to the end of the previous buffer.
• • In the pictures below, buf2 refers to the buffer we
• • are aligning. buf1 refers to previous buffer by addr.
• • Symbol [ means the start of a buffer, ] means the end
• • of a buffer, and | means page boundaries.
• */

+enum buf_end_align_type {

• /**
  

•  * @SAME_PAGE_UNALIGNED: The end of this buffer is on
  

•  * the same page as the end of the previous buffer and
  

•  * is not page aligned. Examples:
  

•  * buf1 ][ buf2 ][ ...
  

•  * buf1 ]|[ buf2 ][ ...
  

•  */
  

• SAME_PAGE_UNALIGNED = 0,
  

• /**
  

•  * @SAME_PAGE_ALIGNED: When the end of the previous buffer
  

•  * is not page aligned, the end of this buffer is on the
  

•  * same page as the end of the previous buffer and is page
  

•  * aligned. When the previous buffer is page aligned, the
  

•  * end of this buffer is aligned to the next page boundary.
  

•  * Examples:
  

•  * buf1 ][ buf2 ]| ...
  

•  * buf1 ]|[ buf2 ]| ...
  

•  */
  

• SAME_PAGE_ALIGNED,
  

• /**
  

•  * @NEXT_PAGE_UNALIGNED: The end of this buffer is on
  

•  * the page next to the end of the previous buffer and
  

•  * is not page aligned. Examples:
  

•  * buf1 ][ buf2 | buf2 ][ ...
  

•  * buf1 ]|[ buf2 | buf2 ][ ...
  

•  */
  

• NEXT_PAGE_UNALIGNED,
  

• /**
  

•  * @NEXT_PAGE_ALIGNED: The end of this buffer is on
  

•  * the page next to the end of the previous buffer and
  

•  * is page aligned. Examples:
  

•  * buf1 ][ buf2 | buf2 ]| ...
  

•  * buf1 ]|[ buf2 | buf2 ]| ...
  

•  */
  

• NEXT_PAGE_ALIGNED,
  

• /**
  

•  * @NEXT_NEXT_UNALIGNED: The end of this buffer is on
  

•  * the page that follows the page after the end of the
  

•  * previous buffer and is not page aligned. Examples:
  

•  * buf1 ][ buf2 | buf2 | buf2 ][ ...
  

•  * buf1 ]|[ buf2 | buf2 | buf2 ][ ...
  

•  */
  

• NEXT_NEXT_UNALIGNED,
  

• /**
  

•  * @LOOP_END: The number of enum values in &buf_end_align_type.
  

•  * It is used for controlling loop termination.
  

•  */
  

• LOOP_END,
  

+};

+static void pr_err_size_seq(struct kunit *test, size_t *sizes, int *seq) +{

• int i;
  

• kunit_err(test, "alloc sizes: ");
  

• for (i = 0; i < BUFFER_NUM; i++)
  

•         pr_cont("[%zu]", sizes[i]);
  

• pr_cont("\n");
  

• kunit_err(test, "free seq: ");
  

• for (i = 0; i < BUFFER_NUM; i++)
  

•         pr_cont("[%d]", seq[i]);
  

• pr_cont("\n");
  

+}

+static bool check_buffer_pages_allocated(struct kunit *test,

•                                  struct binder_alloc *alloc,
  

•                                  struct binder_buffer *buffer,
  

•                                  size_t size)
  

+{

• unsigned long page_addr;
  

• unsigned long end;
  

• int page_index;
  

• end = PAGE_ALIGN(buffer->user_data + size);
  

• page_addr = buffer->user_data;
  

• for (; page_addr < end; page_addr += PAGE_SIZE) {
  

•         page_index = (page_addr - alloc->vm_start) / PAGE_SIZE;
  

•         if (!alloc->pages[page_index] ||
  

•             !list_empty(page_to_lru(alloc->pages[page_index]))) {
  

•                 kunit_err(test, "expect alloc but is %s at page index %d\n",
  

•                           alloc->pages[page_index] ?
  

•                           "lru" : "free", page_index);
  

•                 return false;
  

•         }
  

• }
  

• return true;
  

+}

+static void binder_alloc_test_alloc_buf(struct kunit *test,

•                                 struct binder_alloc *alloc,
  

•                                 struct binder_buffer *buffers[],
  

•                                 size_t *sizes, int *seq)
  

+{

• int i;
  

• for (i = 0; i < BUFFER_NUM; i++) {
  

•         buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0);
  

•         if (IS_ERR(buffers[i]) ||
  

•             !check_buffer_pages_allocated(test, alloc, buffers[i], sizes[i])) {
  

•                 pr_err_size_seq(test, sizes, seq);
  

•                 binder_alloc_test_failures++;
  

•         }
  

• }
  

+}

+static void binder_alloc_test_free_buf(struct kunit *test,

•                                struct binder_alloc *alloc,
  

•                                struct binder_buffer *buffers[],
  

•                                size_t *sizes, int *seq, size_t end)
  

+{

• int i;
  

• for (i = 0; i < BUFFER_NUM; i++)
  

•         binder_alloc_free_buf(alloc, buffers[seq[i]]);
  

• for (i = 0; i <= (end - 1) / PAGE_SIZE; i++) {
  

•         if (list_empty(page_to_lru(alloc->pages[i]))) {
  

•                 pr_err_size_seq(test, sizes, seq);
  

•                 kunit_err(test, "expect lru but is %s at page index %d\n",
  

•                           alloc->pages[i] ? "alloc" : "free", i);
  

•                 binder_alloc_test_failures++;
  

•         }
  

• }
  

+}

+static void binder_alloc_test_free_page(struct kunit *test,

•                                 struct binder_alloc *alloc)
  

+{

• unsigned long count;
  

• int i;
  

• while ((count = list_lru_count(alloc->freelist))) {
  

•         list_lru_walk(alloc->freelist, binder_alloc_free_page,
  

•                       NULL, count);
  

• }
  

• for (i = 0; i < (alloc->buffer_size / PAGE_SIZE); i++) {
  

•         if (alloc->pages[i]) {
  

•                 kunit_err(test, "expect free but is %s at page index %d\n",
  

•                           list_empty(page_to_lru(alloc->pages[i])) ?
  

•                           "alloc" : "lru", i);
  

•                 binder_alloc_test_failures++;
  

•         }
  

• }
  

+}

+static void binder_alloc_test_alloc_free(struct kunit *test,

•                                  struct binder_alloc *alloc,
  

•                                  size_t *sizes, int *seq, size_t end)
  

+{

• struct binder_buffer *buffers[BUFFER_NUM];
  

• binder_alloc_test_alloc_buf(test, alloc, buffers, sizes, seq);
  

• binder_alloc_test_free_buf(test, alloc, buffers, sizes, seq, end);
  

• /* Allocate from lru. */
  

• binder_alloc_test_alloc_buf(test, alloc, buffers, sizes, seq);
  

• if (list_lru_count(alloc->freelist))
  

•         kunit_err(test, "lru list should be empty but is not\n");
  

• binder_alloc_test_free_buf(test, alloc, buffers, sizes, seq, end);
  

• binder_alloc_test_free_page(test, alloc);
  

+}

+static bool is_dup(int *seq, int index, int val) +{

• int i;
  

• for (i = 0; i < index; i++) {
  

•         if (seq[i] == val)
  

•                 return true;
  

• }
  

• return false;
  

+}

+/* Generate BUFFER_NUM factorial free orders. */ +static void permute_frees(struct kunit *test, struct binder_alloc *alloc,

•                   size_t *sizes, int *seq, int index, size_t end)
  

+{

• int i;
  

• if (index == BUFFER_NUM) {
  

•         binder_alloc_test_alloc_free(test, alloc, sizes, seq, end);
  

•         return;
  

• }
  

• for (i = 0; i < BUFFER_NUM; i++) {
  

•         if (is_dup(seq, index, i))
  

•                 continue;
  

•         seq[index] = i;
  

•         permute_frees(test, alloc, sizes, seq, index + 1, end);
  

• }
  

+}

+static void gen_buf_sizes(struct kunit *test, struct binder_alloc *alloc,

•                   size_t *end_offset)
  

+{

• size_t last_offset, offset = 0;
  

• size_t front_sizes[BUFFER_NUM];
  

• size_t back_sizes[BUFFER_NUM];
  

• int seq[BUFFER_NUM] = {0};
  

• int i;
  

• for (i = 0; i < BUFFER_NUM; i++) {
  

•         last_offset = offset;
  

•         offset = end_offset[i];
  

•         front_sizes[i] = offset - last_offset;
  

•         back_sizes[BUFFER_NUM - i - 1] = front_sizes[i];
  

• }
  

• /*
  

•  * Buffers share the first or last few pages.
  

•  * Only BUFFER_NUM - 1 buffer sizes are adjustable since
  

•  * we need one giant buffer before getting to the last page.
  

•  */
  

• back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
  

• permute_frees(test, alloc, front_sizes, seq, 0,
  

•               end_offset[BUFFER_NUM - 1]);
  

• permute_frees(test, alloc, back_sizes, seq, 0, alloc->buffer_size);
  

+}

+static void gen_buf_offsets(struct kunit *test, struct binder_alloc *alloc,

•                     size_t *end_offset, int index)
  

+{

• size_t end, prev;
  

• int align;
  

• if (index == BUFFER_NUM) {
  

•         gen_buf_sizes(test, alloc, end_offset);
  

•         return;
  

• }
  

• prev = index == 0 ? 0 : end_offset[index - 1];
  

• end = prev;
  

• BUILD_BUG_ON(BUFFER_MIN_SIZE * BUFFER_NUM >= PAGE_SIZE);
  

• for (align = SAME_PAGE_UNALIGNED; align < LOOP_END; align++) {
  

•         if (align % 2)
  

•                 end = ALIGN(end, PAGE_SIZE);
  

•         else
  

•                 end += BUFFER_MIN_SIZE;
  

•         end_offset[index] = end;
  

•         gen_buf_offsets(test, alloc, end_offset, index + 1);
  

• }
  

+}

struct binder_alloc_test { struct binder_alloc alloc; struct list_lru binder_test_freelist; @@ -56,6 +315,25 @@ static void binder_alloc_test_mmap(struct kunit *test) KUNIT_EXPECT_TRUE(test, list_is_last(&buf->entry, &alloc->buffers)); }

+/**

• • binder_alloc_exhaustive_test() - Exhaustively test alloc and free of buffer pages.
• • @test: The test context object.
• • Allocate BUFFER_NUM buffers to cover all page alignment cases,
• • then free them in all orders possible. Check that pages are
• • correctly allocated, put onto lru when buffers are freed, and
• • are freed when binder_alloc_free_page() is called.
• */

+static void binder_alloc_exhaustive_test(struct kunit *test) +{

• struct binder_alloc_test *priv = test->priv;
  

• size_t end_offset[BUFFER_NUM];
  

• gen_buf_offsets(test, &priv->alloc, end_offset, 0);
  

• KUNIT_EXPECT_EQ(test, binder_alloc_test_failures, 0);
  

+}

/* ===== End test cases ===== */

static void binder_alloc_test_vma_close(struct vm_area_struct *vma) @@ -149,6 +427,7 @@ static void binder_alloc_test_exit(struct kunit *test) static struct kunit_case binder_alloc_test_cases[] = { KUNIT_CASE(binder_alloc_test_init_freelist), KUNIT_CASE(binder_alloc_test_mmap),

• KUNIT_CASE(binder_alloc_exhaustive_test),
  {}
  

};

-- 2.50.0.727.gbf7dc18ff4-goog

LGTM!

Acked-by: Carlos Llamas cmllamas@google.com

Kees Cook kees@kernel.org writes:

For both stringify functions, snprintf is potentially unsafe. In the spirit of recent string API discussions, please switch to using a seq_buf:

static void stringify_free_seq(struct kunit *test, int *seq, seq_buf *buf) { unsigned int i;

for (i = 0; i < BUFFER_NUM; i++) seq_buf_printf(buf, "[%d]", seq[i]) KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(buf)); } ...

DECLARE_SEQ_BUF(freeseq_buf, FREESEQ_BUFLEN); ... stringify_free_seq(test, tc->free_sequence, &freeseq_buf);

Thanks for calling attention to this! Will be fixed for v4!

...

static bool check_buffer_pages_allocated(struct kunit *test, @@ -124,28 +164,30 @@ static bool check_buffer_pages_allocated(struct kunit *test, return true; }

...

-static void binder_alloc_test_alloc_buf(struct kunit *test,

• 			struct binder_alloc *alloc,
  

• 			struct binder_buffer *buffers[],
  

• 			size_t *sizes, int *seq)
  

+static unsigned long binder_alloc_test_alloc_buf(struct kunit *test,

• 				 struct binder_alloc *alloc,
  

• 				 struct binder_buffer *buffers[],
  

• 				 size_t *sizes, int *seq)
  

  {
• unsigned long failures = 0; int i;

...

for (i = 0; i < BUFFER_NUM; i++) { buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0); if (IS_ERR(buffers[i]) ||

•     !check_buffer_pages_allocated(test, alloc, buffers[i], sizes[i]))  
  

{

• 	pr_err_size_seq(test, sizes, seq);
  

• 	binder_alloc_test_failures++;
  

• }
  

•     !check_buffer_pages_allocated(test, alloc, buffers[i], sizes[i]))
  

• 	failures++;
  

  }
• return failures; }

...

-static void binder_alloc_test_free_buf(struct kunit *test,

• 		       struct binder_alloc *alloc,
  

• 		       struct binder_buffer *buffers[],
  

• 		       size_t *sizes, int *seq, size_t end)
  

+static unsigned long binder_alloc_test_free_buf(struct kunit *test,

• 				struct binder_alloc *alloc,
  

• 				struct binder_buffer *buffers[],
  

• 				size_t *sizes, int *seq, size_t end)
  

  {
• unsigned long failures = 0; int i;

...

for (i = 0; i < BUFFER_NUM; i++) @@ -153,17 +195,19 @@ static void binder_alloc_test_free_buf(struct kunit *test,

...

for (i = 0; i <= (end - 1) / PAGE_SIZE; i++) { if (list_empty(page_to_lru(alloc->pages[i]))) {

• 	pr_err_size_seq(test, sizes, seq);
  kunit_err(test, "expect lru but is %s at page index %d\n",
  	  alloc->pages[i] ? "alloc" : "free", i);
  

• 	binder_alloc_test_failures++;
  

• 	failures++;
  

  } }
• return failures; }

...

-static void binder_alloc_test_free_page(struct kunit *test,

• 			struct binder_alloc *alloc)
  

+static unsigned long binder_alloc_test_free_page(struct kunit *test,

• 				 struct binder_alloc *alloc)
  

  {
• unsigned long failures = 0; unsigned long count; int i;

...

@@ -177,27 +221,70 @@ static void binder_alloc_test_free_page(struct kunit *test, kunit_err(test, "expect free but is %s at page index %d\n", list_empty(page_to_lru(alloc->pages[i])) ? "alloc" : "lru", i);

• 	binder_alloc_test_failures++;
  

• 	failures++;
  

  } }
• return failures; }

...

-static void binder_alloc_test_alloc_free(struct kunit *test, +/* Executes one full test run for the given test case. */ +static bool binder_alloc_test_alloc_free(struct kunit *test, struct binder_alloc *alloc,

• 			 size_t *sizes, int *seq, size_t end)
  

• 			 struct binder_alloc_test_case_info *tc,
  

• 			 size_t end)
  

  {
• unsigned long pages = PAGE_ALIGN(end) / PAGE_SIZE; struct binder_buffer *buffers[BUFFER_NUM];

• binder_alloc_test_alloc_buf(test, alloc, buffers, sizes, seq);
• binder_alloc_test_free_buf(test, alloc, buffers, sizes, seq, end);

• unsigned long failures;
• bool failed = false;
• failures = binder_alloc_test_alloc_buf(test, alloc, buffers,

• 			       tc->buffer_sizes,
  

• 			       tc->free_sequence);
  

• failed = failed || failures;
• KUNIT_EXPECT_EQ_MSG(test, failures, 0,

• 	    "Initial allocation failed: %lu/%u buffers with errors",
  

• 	    failures, BUFFER_NUM);
  

• failures = binder_alloc_test_free_buf(test, alloc, buffers,

• 			      tc->buffer_sizes,
  

• 			      tc->free_sequence, end);
  

• failed = failed || failures;
• KUNIT_EXPECT_EQ_MSG(test, failures, 0,

• 	    "Initial buffers not freed correctly: %lu/%lu pages not on lru  
  

list",

• 	    failures, pages);
  

...

/* Allocate from lru. */

• binder_alloc_test_alloc_buf(test, alloc, buffers, sizes, seq);
• if (list_lru_count(alloc->freelist))

• kunit_err(test, "lru list should be empty but is not\n");
  

• binder_alloc_test_free_buf(test, alloc, buffers, sizes, seq, end);
• binder_alloc_test_free_page(test, alloc);

• failures = binder_alloc_test_alloc_buf(test, alloc, buffers,

• 			       tc->buffer_sizes,
  

• 			       tc->free_sequence);
  

• failed = failed || failures;
• KUNIT_EXPECT_EQ_MSG(test, failures, 0,

• 	    "Reallocation failed: %lu/%u buffers with errors",
  

• 	    failures, BUFFER_NUM);
  

• failures = list_lru_count(alloc->freelist);
• failed = failed || failures;
• KUNIT_EXPECT_EQ_MSG(test, failures, 0,

• 	    "lru list should be empty after reallocation but still has %lu  
  

pages",

• 	    failures);
  

• failures = binder_alloc_test_free_buf(test, alloc, buffers,

• 			      tc->buffer_sizes,
  

• 			      tc->free_sequence, end);
  

• failed = failed || failures;
• KUNIT_EXPECT_EQ_MSG(test, failures, 0,

• 	    "Reallocated buffers not freed correctly: %lu/%lu pages not on  
  

lru list",

• 	    failures, pages);
  

• failures = binder_alloc_test_free_page(test, alloc);
• failed = failed || failures;
• KUNIT_EXPECT_EQ_MSG(test, failures, 0,

• 	    "Failed to clean up allocated pages: %lu/%lu pages still  
  

installed",

• 	    failures, (alloc->buffer_size / PAGE_SIZE));
  

• return failed; }

...

static bool is_dup(int *seq, int index, int val) @@ -213,24 +300,44 @@ static bool is_dup(int *seq, int index, int val)

...

/* Generate BUFFER_NUM factorial free orders. */ static void permute_frees(struct kunit *test, struct binder_alloc *alloc,

• 	  size_t *sizes, int *seq, int index, size_t end)
  

• 	  struct binder_alloc_test_case_info *tc,
  

• 	  unsigned long *runs, unsigned long *failures,
  

• 	  int index, size_t end)
  

  {
• bool case_failed; int i;

...

if (index == BUFFER_NUM) {

• binder_alloc_test_alloc_free(test, alloc, sizes, seq, end);
  

• char freeseq_buf[FREESEQ_BUFLEN];
  

• case_failed = binder_alloc_test_alloc_free(test, alloc, tc, end);
  

• *runs += 1;
  

• *failures += case_failed;
  

• if (case_failed || PRINT_ALL_CASES) {
  

• 	stringify_free_seq(test, tc->free_sequence, freeseq_buf,
  

• 			   FREESEQ_BUFLEN);
  

• 	kunit_err(test, "case %lu: [%s] | %s - %s - %s", *runs,
  

• 		  case_failed ? "FAILED" : "PASSED",
  

• 		  tc->front_pages ? "front" : "back ",
  

• 		  tc->alignments, freeseq_buf);
  

• }
  

• return; } for (i = 0; i < BUFFER_NUM; i++) {

• if (is_dup(seq, index, i))
  

• if (is_dup(tc->free_sequence, index, i))
  continue;
  

• seq[index] = i;
  

• permute_frees(test, alloc, sizes, seq, index + 1, end);
  

• tc->free_sequence[index] = i;
  

• permute_frees(test, alloc, tc, runs, failures, index + 1, end);
  

  } }

...

-static void gen_buf_sizes(struct kunit *test, struct binder_alloc *alloc,

• 	  size_t *end_offset)
  

+static void gen_buf_sizes(struct kunit *test,

• 	  struct binder_alloc *alloc,
  

• 	  struct binder_alloc_test_case_info *tc,
  

• 	  size_t *end_offset, unsigned long *runs,
  

• 	  unsigned long *failures)
  

  { size_t last_offset, offset = 0; size_t front_sizes[BUFFER_NUM];

@@ -238,31 +345,45 @@ static void gen_buf_sizes(struct kunit *test, struct binder_alloc *alloc, int seq[BUFFER_NUM] = {0}; int i;

...

• tc->free_sequence = seq; for (i = 0; i < BUFFER_NUM; i++) { last_offset = offset; offset = end_offset[i]; front_sizes[i] = offset - last_offset; back_sizes[BUFFER_NUM - i - 1] = front_sizes[i]; }
• back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
• /*
  • Buffers share the first or last few pages.
  • Only BUFFER_NUM - 1 buffer sizes are adjustable since
  • we need one giant buffer before getting to the last page.
  */

• back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
• permute_frees(test, alloc, front_sizes, seq, 0,

• tc->front_pages = true;
• tc->buffer_sizes = front_sizes;
• permute_frees(test, alloc, tc, runs, failures, 0, end_offset[BUFFER_NUM - 1]);

• permute_frees(test, alloc, back_sizes, seq, 0, alloc->buffer_size);

• tc->front_pages = false;
• tc->buffer_sizes = back_sizes;
• permute_frees(test, alloc, tc, runs, failures, 0, alloc->buffer_size); }

...

static void gen_buf_offsets(struct kunit *test, struct binder_alloc *alloc,

• 	    size_t *end_offset, int index)
  

• 	    size_t *end_offset, int *alignments,
  

• 	    unsigned long *runs, unsigned long *failures,
  

• 	    int index)
  

  { size_t end, prev; int align;

...

if (index == BUFFER_NUM) {

• gen_buf_sizes(test, alloc, end_offset);
  

• struct binder_alloc_test_case_info tc = {0};
  

• stringify_alignments(test, alignments, tc.alignments,
  

• 		     ALIGNMENTS_BUFLEN);
  

• gen_buf_sizes(test, alloc, &tc, end_offset, runs, failures);
  

  return; } prev = index == 0 ? 0 : end_offset[index - 1];

@@ -276,7 +397,9 @@ static void gen_buf_offsets(struct kunit *test, struct binder_alloc *alloc, else end += BUFFER_MIN_SIZE; end_offset[index] = end;

• gen_buf_offsets(test, alloc, end_offset, index + 1);
  

• alignments[index] = align;
  

• gen_buf_offsets(test, alloc, end_offset, alignments, runs,
  

• 		failures, index + 1);
  

  } }

...

@@ -328,10 +451,15 @@ static void binder_alloc_exhaustive_test(struct kunit *test) { struct binder_alloc_test *priv = test->priv; size_t end_offset[BUFFER_NUM];

• int alignments[BUFFER_NUM];
• unsigned long failures = 0;
• unsigned long runs = 0;

...

• gen_buf_offsets(test, &priv->alloc, end_offset, 0);

• gen_buf_offsets(test, &priv->alloc, end_offset, alignments, &runs,

• 	&failures, 0);
  

...

• KUNIT_EXPECT_EQ(test, binder_alloc_test_failures, 0);

• KUNIT_EXPECT_EQ(test, runs, TOTAL_EXHAUSTIVE_CASES);
• KUNIT_EXPECT_EQ(test, failures, 0); }

...

/* ===== End test cases ===== */

2.50.0.727.gbf7dc18ff4-goog

Otherwise looks good to me.