On 12/18/20 3:56 PM, Takashi Iwai wrote:
Currently the standard memory allocator (snd_dma_malloc_pages*()) passes the byte size to allocate as is. Most of the backends allocates real pages, hence the actual allocations are aligned in page size. However, the genalloc doesn't seem assuring the size alignment, hence it may result in the access outside the buffer when the whole memory pages are exposed via mmap.
For avoiding such inconsistencies, this patch makes the allocation size always to be aligned in page size.
Note that, after this change, snd_dma_buffer.bytes field contains the aligned size, not the originally requested size. This value is also used for releasing the pages in return.
Signed-off-by: Takashi Iwai tiwai@suse.de
FWIW
Reviewed-by: Lars-Peter Clausen lars@metafoo.de
sound/core/memalloc.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 0f335162f87c..966bef5acc75 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -133,6 +133,7 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size, if (WARN_ON(!dmab)) return -ENXIO;
- size = PAGE_ALIGN(size); dmab->dev.type = type; dmab->dev.dev = device; dmab->bytes = 0;