From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: crash in gart_unmap_page() with master snapshot (commit e1ef035d272e) Date: Fri, 4 Jan 2019 09:53:18 +0100 Message-ID: <20190104085318.GA15939@lst.de> References: <20190102083854.GA28932@unicorn.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190102083854.GA28932@unicorn.suse.cz> Sender: linux-kernel-owner@vger.kernel.org To: Michal Kubecek Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Joerg Roedel List-Id: iommu@lists.linux-foundation.org Hi Michal, can you try the patch below? --- >>From 6b22ae23a1971646dacc8a0ad313a6329a04cf98 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 4 Jan 2019 09:50:33 +0100 Subject: x86/amd_gart: fix unmapping of non-GART mappings In many cases we don't have to create a GART mapping at all, which also means there is nothing to unmap. Fix the range check that was incorrectly modified when removing the mapping_error method. Fixes: 9e8aa6b546 ("x86/amd_gart: remove the mapping_error dma_map_ops method") Reported-by: Michal Kubecek Signed-off-by: Christoph Hellwig --- arch/x86/kernel/amd_gart_64.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c index e0ff3ac8c127..2c0aa34af69c 100644 --- a/arch/x86/kernel/amd_gart_64.c +++ b/arch/x86/kernel/amd_gart_64.c @@ -256,7 +256,15 @@ static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr, int npages; int i; - if (dma_addr == DMA_MAPPING_ERROR || + if (WARN_ON_ONCE(dma_addr == DMA_MAPPING_ERROR)) + return; + + /* + * This driver will not always use a GART mapping, but might have + * created a direct mapping instead. If that is the case there is + * nothing to unmap here. + */ + if (dma_addr < iommu_bus_base || dma_addr >= iommu_bus_base + iommu_size) return; -- 2.20.1