kernel/drivers/android/binder_alloc_selftest.c, branch 0x221E-v0.0-v7.0

binder: Convert binder_alloc selftests to KUnit

2025-07-16T12:11:59Z

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 Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/20250714185321.2417234-6-ynaffit@google.com Signed-off-by: Greg Kroah-Hartman

binder: Store lru freelist in binder_alloc

2025-07-16T12:11:58Z

Store a pointer to the free pages list that the binder allocator should use for a process inside of struct binder_alloc. This change allows binder allocator code to be tested and debugged deterministically while a system is using binder; i.e., without interfering with other binder processes and independently of the shrinker. This is necessary to convert the current binder_alloc_selftest into a kunit test that does not rely on hijacking an existing binder_proc to run. A binder process's binder_alloc->freelist should not be changed after it is initialized. A sole exception is the process that runs the existing binder_alloc selftest. Its freelist can be temporarily replaced for the duration of the test because it runs as a single thread before any pages can be added to the global binder freelist, and the test frees every page it allocates before dropping the binder_selftest_lock. This exception allows the existing selftest to be used to check for regressions, but it will be dropped when the binder_alloc tests are converted to kunit in a subsequent patch in this series. Signed-off-by: Tiffany Yang Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/20250714185321.2417234-3-ynaffit@google.com Signed-off-by: Greg Kroah-Hartman

binder: Fix selftest page indexing

2025-07-16T12:11:58Z

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 Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/20250714185321.2417234-2-ynaffit@google.com Signed-off-by: Greg Kroah-Hartman

binder: rename alloc->buffer to vm_start

2024-12-24T08:35:23Z

The alloc->buffer field in struct binder_alloc stores the starting address of the mapped vma, rename this field to alloc->vm_start to better reflect its purpose. It also avoids confusion with the binder buffer concept, e.g. transaction->buffer. No functional changes in this patch. Reviewed-by: Suren Baghdasaryan Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20241210143114.661252-7-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: replace alloc->vma with alloc->mapped

2024-12-24T08:35:23Z

It is unsafe to use alloc->vma outside of the mmap_sem. Instead, add a new boolean alloc->mapped to save the vma state (mapped or unmmaped) and use this as a replacement for alloc->vma to validate several paths. Using the alloc->vma caused several performance and security issues in the past. Now that it has been replaced with either vm_lookup() or the alloc->mapped state, we can finally remove it. Cc: Minchan Kim Cc: Liam R. Howlett Cc: Matthew Wilcox Cc: Suren Baghdasaryan Reviewed-by: Suren Baghdasaryan Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20241210143114.661252-6-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: store shrinker metadata under page->private

2024-12-24T08:35:23Z

Instead of pre-allocating an entire array of struct binder_lru_page in alloc->pages, install the shrinker metadata under page->private. This ensures the memory is allocated and released as needed alongside pages. By converting the alloc->pages[] into an array of struct page pointers, we can access these pages directly and only reference the shrinker metadata where it's being used (e.g. inside the shrinker's callback). Rename struct binder_lru_page to struct binder_shrinker_mdata to better reflect its purpose. Add convenience functions that wrap the allocation and freeing of pages along with their shrinker metadata. Note I've reworked this patch to avoid using page->lru and page->index directly, as Matthew pointed out that these are being removed [1]. Link: https://lore.kernel.org/all/ZzziucEm3np6e7a0@casper.infradead.org/ [1] Cc: Matthew Wilcox Cc: Liam R. Howlett Reviewed-by: Suren Baghdasaryan Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20241210143114.661252-5-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

android: binder: fix a kernel-doc enum warning

2023-12-05T23:48:26Z

Add kernel-doc notation for @LOOP_END to prevent a kernel-doc warning. binder_alloc_selftest.c:76: warning: Enum value 'LOOP_END' not described in enum 'buf_end_align_type' Signed-off-by: Randy Dunlap Cc: Greg Kroah-Hartman Cc: Arve Hjønnevåg Cc: Todd Kjos Cc: Martijn Coenen Cc: Joel Fernandes Cc: Christian Brauner Cc: Carlos Llamas Cc: Suren Baghdasaryan Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/20231205225324.32362-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman

binder: rename lru shrinker utilities

2023-12-05T00:23:40Z

Now that the page allocation step is done separately we should rename the binder_free_page_range() and binder_allocate_page_range() functions to provide a more accurate description of what they do. Lets borrow the freelist concept used in other parts of the kernel for this. No functional change here. Signed-off-by: Carlos Llamas Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20231201172212.1813387-23-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: remove pid param in binder_alloc_new_buf()

2023-12-05T00:23:39Z

Binder attributes the buffer allocation to the current->tgid everytime. There is no need to pass this as a parameter so drop it. Also add a few touchups to follow the coding guidelines. No functional changes are introduced in this patch. Reviewed-by: Alice Ryhl Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20231201172212.1813387-13-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: keep vma addresses type as unsigned long

2023-12-05T00:23:38Z

The vma addresses in binder are currently stored as void __user *. This requires casting back and forth between the mm/ api which uses unsigned long. Since we also do internal arithmetic on these addresses we end up having to cast them _again_ to an integer type. Lets stop all the unnecessary casting which kills code readability and store the virtual addresses as the native unsigned long from mm/. Note that this approach is preferred over uintptr_t as Linus explains in [1]. Opportunistically add a few cosmetic touchups. Link: https://lore.kernel.org/all/CAHk-=wj2OHy-5e+srG1fy+ZU00TmZ1NFp6kFLbVLMXHe7A1d-g@mail.gmail.com/ [1] Signed-off-by: Carlos Llamas Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20231201172212.1813387-10-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman