From 704f2c20eaa566f6906e8812b6e2115889bd753d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 22 Sep 2018 20:47:26 +0200 Subject: [PATCH] dma-direct: reject highmem pages from dma_alloc_from_contiguous dma_alloc_from_contiguous can return highmem pages depending on the setup, which a plain non-remapping DMA allocator can't handle. Detect this case and fail the allocation. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy --- kernel/dma/direct.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 680287779b0a..c49849bcced6 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -162,6 +162,18 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, if (!page) return NULL; + if (PageHighMem(page)) { + /* + * Depending on the cma= arguments and per-arch setup + * dma_alloc_from_contiguous could return highmem pages. + * Without remapping there is no way to return them here, + * so log an error and fail. + */ + dev_info(dev, "Rejecting highmem page from CMA.\n"); + __dma_direct_free_pages(dev, size, page); + return NULL; + } + ret = page_address(page); if (force_dma_unencrypted()) { set_memory_decrypted((unsigned long)ret, 1 << get_order(size)); -- 2.30.2