On Fri, Jun 27, 2025 at 4:38 PM Tiffany Yang <[email protected]> wrote: > > Add setup and teardown for testing binder allocator code with KUnit. > Include minimal test cases to verify that tests are initialized > correctly. > > Signed-off-by: Tiffany Yang <[email protected]> > --- > 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 <[email protected]>"); > +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 >
These KUnit changes to include/kunit/test.h and lib/kunit/user_alloc.c seem ok to me. I also tested this and it seems to be running well. Tested-by: Rae Moar <[email protected]> Thanks! -Rae
