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From: Christoph Hellwig <hch@lst.de>
To: "Michel Dänzer" <michel@daenzer.net>
Cc: Sibren Vasse <freedesktop@sibrenvasse.nl>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	x86@kernel.org, dri-devel@lists.freedesktop.org,
	iommu@lists.linux-foundation.org, amd-gfx@lists.freedesktop.org,
	Robin Murphy <robin.murphy@arm.com>,
	Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: amdgpu/TTM oopses since merging swiotlb_dma_ops into the dma_direct code
Date: Thu, 10 Jan 2019 14:57:41 +0100	[thread overview]
Message-ID: <20190110135741.GA9255@lst.de> (raw)
In-Reply-To: <61f8f660-005c-190c-c08f-b563de2eae18@daenzer.net>

On Thu, Jan 10, 2019 at 10:59:02AM +0100, Michel Dänzer wrote:
> 
> Hi Christoph,
> 
> 
> https://bugs.freedesktop.org/109234 (please ignore comments #6-#9) was
> bisected to your commit 55897af63091 "dma-direct: merge swiotlb_dma_ops
> into the dma_direct code". Any ideas?

From the trace it looks like we git the case where swiotlb tries
to copy back data from a bounce buffer, but hits a dangling or NULL
pointer.  So a couple questions for the submitter:

 - does the system have more than 4GB memory and thus use swiotlb?
   (check /proc/meminfo, and if something SWIOTLB appears in dmesg)
 - does the device this happens on have a DMA mask smaller than
   the available memory, that is should swiotlb be used here to start
   with?
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  reply	other threads:[~2019-01-10 13:57 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-10  9:59 amdgpu/TTM oopses since merging swiotlb_dma_ops into the dma_direct code Michel Dänzer
2019-01-10 13:57 ` Christoph Hellwig [this message]
2019-01-10 14:00   ` Christian König
     [not found]     ` <a3f0fd49-2286-ee2a-f0e8-dfe82aac73fb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2019-01-10 14:48       ` Christoph Hellwig
     [not found]         ` <20190110144837.GA10362-jcswGhMUV9g@public.gmane.org>
2019-01-10 17:52           ` Sibren Vasse
2019-01-14 18:10             ` Christoph Hellwig
     [not found]               ` <20190114181041.GB8897-jcswGhMUV9g@public.gmane.org>
2019-01-14 19:00                 ` Sibren Vasse
2019-01-14 17:22           ` Michel Dänzer
     [not found]   ` <20190110135741.GA9255-jcswGhMUV9g@public.gmane.org>
2019-01-10 15:26     ` Sibren Vasse
     [not found]       ` <CAF=iVctGGs1OzHBg6MgpxrFbT_19T4YvH8muBZtsLJBDwGhrvQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-01-10 17:05         ` Konrad Rzeszutek Wilk
     [not found]           ` <20190110170557.GD27546-he5eyhs8q0BAdwtm4QZOy9BPR1lH4CV8@public.gmane.org>
2019-01-10 17:34             ` Sibren Vasse
2019-01-14 18:13       ` Christoph Hellwig
     [not found]         ` <20190114181314.GC8897-jcswGhMUV9g@public.gmane.org>
2019-01-14 19:32           ` Sibren Vasse

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