From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Wed, 01 Jul 2015 15:46:38 +0200 Subject: [PATCH v2] arm: dma-mapping: fix off-by-one error in bitmap size check In-Reply-To: <1435754903-25108-1-git-send-email-m.szyprowski@samsung.com> References: <1435754903-25108-1-git-send-email-m.szyprowski@samsung.com> Message-ID: <1435758406-6989-1-git-send-email-m.szyprowski@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 CC: stable at vger.kernel.org # v3.15+ --- V2 fixed build problem caused by a hurry in patch preparation. My fault. I'm really sorry for the noise. Best regards Marek Szyprowski, PhD Samsung R&D Institute Poland --- arch/arm/mm/dma-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index a64b7f621067..05619542a1c0 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -2015,7 +2015,7 @@ 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; -- 1.9.2