From c6622a425acd1d2f3a443cd39b490a8777b622d7 Mon Sep 17 00:00:00 2001 From: Nicolin Chen Date: Fri, 26 Jul 2019 12:34:32 -0700 Subject: [PATCH] dma-contiguous: do not overwrite align in dma_alloc_contiguous() The dma_alloc_contiguous() limits align at CONFIG_CMA_ALIGNMENT for cma_alloc() however it does not restore it for the fallback routine. This will result in a size mismatch between the allocation and free when running into the fallback routines after cma_alloc() fails, if the align is larger than CONFIG_CMA_ALIGNMENT. This patch adds a cma_align to take care of cma_alloc() and prevent the align from being overwritten. Fixes: fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") Reported-by: Dafna Hirschfeld Signed-off-by: Nicolin Chen Signed-off-by: Christoph Hellwig --- kernel/dma/contiguous.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c index bfc0c17f2a3d..ea8259f53eda 100644 --- a/kernel/dma/contiguous.c +++ b/kernel/dma/contiguous.c @@ -243,8 +243,9 @@ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) /* CMA can be used only in the context which permits sleeping */ if (cma && gfpflags_allow_blocking(gfp)) { - align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); - page = cma_alloc(cma, count, align, gfp & __GFP_NOWARN); + size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); + + page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN); } /* Fallback allocation of normal pages */