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
---
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 +++++++++++++++++++++
include/kunit/test.h | 12 ++
lib/kunit/user_alloc.c | 4 +-
11 files changed, 222 insertions(+), 8 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
+ 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
+
+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");
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-googOn Wed, 2 Jul 2025 at 09:05, Tiffany Yang <ynaffit@google.com> 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
> ---
This looks great, thanks.
One small request: could we split the change to expose
kunit_attach_mm() into a separate commit? That'd make it easier for
people to backport independently of binder changes if other tests want
to use this, too.
Cheers,
-- David
> 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 +++++++++++++++++++++
> include/kunit/test.h | 12 ++
> lib/kunit/user_alloc.c | 4 +-
> 11 files changed, 222 insertions(+), 8 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
> + 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
> +
> +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");
> 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
>
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