From: Joerg Roedel <joro@8bytes.org>
To: Mark Hounschell <markh@compro.net>
Cc: iommu@lists.linux-foundation.org,
Linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: BUG at drivers/iommu/amd_iommu.c:1436!
Date: Tue, 22 Nov 2016 09:45:22 +0100 [thread overview]
Message-ID: <20161122084522.GF2078@8bytes.org> (raw)
In-Reply-To: <4f6afa52-9634-79f4-01af-1ae047aa83f7@compro.net>
On Mon, Nov 21, 2016 at 04:47:59PM -0500, Mark Hounschell wrote:
> OK, I did get this message before the reported BUG message.
>
> gpiohsd gpiohsd: DMA-API: device driver tries to free DMA memory it has not allocated [device address=0xffffffffffee8000] [size=8192 bytes]
>
> But I've verified that the dma_addr_t that I get for the alloc, and
> also use for the free is 0x00000000ffee8000 in this case? Is device
> "address=0xffffffffffee8000" in that message a bug in the message or
> do we have a sign extended address problem? It seems strange to me,
> I've never seen a dma_addr_t given, when using the iommu, that
> high. In the past I've seen them as usually 0x00xxxxxx?
>
> I have also verified that simply changing from
> pci_alloc/free_consistent to the newer DMA API fixes my issue and I
> get no such messages.
Yes, this looks like a sign-extension bug somewhere. But its not in the
amd-iommu driver, because dma-debug also sees it. And from what I can
tell the dma-api interface seems to be fine. It consistently uses
dma_addr_t to pass these values around.
Where can I find the source of the failing code? I need exactly the code
version that triggers the problem.
Joerg
next prev parent reply other threads:[~2016-11-22 8:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-17 19:13 Mark Hounschell
2016-11-17 21:41 ` Joerg Roedel
2016-11-17 21:53 ` Mark Hounschell
2016-11-17 22:00 ` Joerg Roedel
2016-11-18 14:04 ` Mark Hounschell
2016-11-21 15:32 ` Joerg Roedel
2016-11-21 21:47 ` Mark Hounschell
2016-11-22 8:45 ` Joerg Roedel [this message]
2016-11-22 19:53 ` Mark Hounschell
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