From f52ac912c14c5bf426c0f9e0c6236dbcdf61664e Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 18 Dec 2020 15:56:24 +0100 Subject: [PATCH] ALSA: memalloc: Align buffer allocations in page size commit 5c1733e33c888a3cb7f576564d8ad543d5ad4a9e upstream. 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. Reviewed-by: Lars-Peter Clausen Link: https://lore.kernel.org/r/20201218145625.2045-2-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/memalloc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 78ffe445d775..a67fbcabfa67 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -177,6 +177,7 @@ 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;