From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout1.samsung.com ([203.254.224.24]:34616 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754306AbbGBAuJ (ORCPT ); Wed, 1 Jul 2015 20:50:09 -0400 Received: from epcpsbgr4.samsung.com (u144.gpu120.samsung.co.kr [203.254.230.144]) by mailout1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NQU00BLI4ZJJF70@mailout1.samsung.com> for stable@vger.kernel.org; Thu, 02 Jul 2015 09:50:07 +0900 (KST) Date: Thu, 02 Jul 2015 09:50:07 +0900 From: Hyungwon Hwang To: Marek Szyprowski Cc: linux-arm-kernel@lists.infradead.org, Russell King - ARM Linux , Inki Dae , stable@vger.kernel.org Subject: Re: [PATCH v2] arm: dma-mapping: fix off-by-one error in bitmap size check Message-id: <20150702095007.1d20ed75@hwh-ubuntu> In-reply-to: <1435758406-6989-1-git-send-email-m.szyprowski@samsung.com> References: <1435754903-25108-1-git-send-email-m.szyprowski@samsung.com> <1435758406-6989-1-git-send-email-m.szyprowski@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: Dear Marek, On Wed, 01 Jul 2015 15:46:38 +0200 Marek Szyprowski wrote: > 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@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; With this patch, the error disappeared on my private arm board. Also, the fix is clearly reasonable. Reviewed-by: Hyungwon Hwang