From cd536db050993f7c220a6cfb01de5356032b6f8e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 18 Oct 2022 02:10:11 -0700 Subject: [PATCH] dma-buf: Proactively round up to kmalloc bucket size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of discovering the kmalloc bucket size _after_ allocation, round up proactively so the allocation is explicitly made for the full size, allowing the compiler to correctly reason about the resulting size of the buffer through the existing __alloc_size() hint. Cc: Sumit Semwal Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Reviewed-by: Christian König Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221018090858.never.941-kees@kernel.org --- drivers/dma-buf/dma-resv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index e3885c90a3ac..1c76aed8e262 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -98,12 +98,17 @@ static void dma_resv_list_set(struct dma_resv_list *list, static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences) { struct dma_resv_list *list; + size_t size; - list = kmalloc(struct_size(list, table, max_fences), GFP_KERNEL); + /* Round up to the next kmalloc bucket size. */ + size = kmalloc_size_roundup(struct_size(list, table, max_fences)); + + list = kmalloc(size, GFP_KERNEL); if (!list) return NULL; - list->max_fences = (ksize(list) - offsetof(typeof(*list), table)) / + /* Given the resulting bucket size, recalculated max_fences. */ + list->max_fences = (size - offsetof(typeof(*list), table)) / sizeof(*list->table); return list;