From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Kubecek Subject: Re: crash in gart_unmap_page() with master snapshot (commit e1ef035d272e) Date: Fri, 4 Jan 2019 22:55:52 +0100 Message-ID: <20190104215552.GF28932@unicorn.suse.cz> References: <20190102083854.GA28932@unicorn.suse.cz> <20190104085318.GA15939@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190104085318.GA15939@lst.de> Sender: linux-kernel-owner@vger.kernel.org To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Joerg Roedel List-Id: iommu@lists.linux-foundation.org On Fri, Jan 04, 2019 at 09:53:18AM +0100, Christoph Hellwig wrote: > Hi Michal, > > can you try the patch below? The machine has been running with it for 12 hours now without any apparent problem. Without the patch it crashed once after ~10 minutes and once after ~3 hours (then I switched back to 4.20). Thanks a lot for quick help. Tested-by: Michal Kubecek > > --- > 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 >