From: Marek Szyprowski Date: Wed, 8 Jul 2015 12:21:55 +0000 (+0100) Subject: ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check X-Git-Tag: v4.1.5~114 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=50c301372e86ce52a897ead3f55044811a9ebb57;p=users%2Fjedix%2Flinux-maple.git ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check commit 462859aa7bbe1ac83ec4377a0a06fe60778f3f27 upstream. nr_bitmaps member of mapping structure stores the number of already allocated bitmaps and it is interpreted as loop iterator (it starts from 0 not from 1), so a comparison against number of possible bitmap extensions should include this fact. This patch fixes this by changing the extension failure condition. This issue has been introduced by commit 4d852ef8c2544ce21ae41414099a7504c61164a0 ("arm: dma-mapping: Add support to extend DMA IOMMU mappings"). Reported-by: Hyungwon Hwang Signed-off-by: Marek Szyprowski Reviewed-by: Hyungwon Hwang Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 7e7583ddd6076..6e4b9ff22ef3c 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1953,7 +1953,7 @@ static int extend_iommu_mapping(struct dma_iommu_mapping *mapping) { int next_bitmap; - if (mapping->nr_bitmaps > mapping->extensions) + if (mapping->nr_bitmaps >= mapping->extensions) return -EINVAL; next_bitmap = mapping->nr_bitmaps;