Re: Kernel Oops: iommu related?

[Mark Hounschell <markh-n2QNKt385d+sTnJN9+BGXg@public.gmane.org>]

On 02/12/2015 01:08 PM, Joerg Roedel wrote:
> On Thu, Feb 12, 2015 at 12:53:42PM -0500, Mark Hounschell wrote:
>> This happens immediately after unloading one of our out of kernel GPL drivers.
>> The driver has done NOTHING other than load at bootup.  I'm running a 3.18.7
>> kernel (x86_64) on an AMD platform. I can't see anything obviously wrong in our
>> driver. It works fine when the iommu is disabled. This particular machine has 7 of
>> our cards in it. Four in one expansion rack and 3 in another. The 2 PCI expansion
>> racks use pci-e interface cards installed in the MB.
>>
>> Feb 12 10:47:15 harley kernel: AMD-Vi: Event logged [IO_PAGE_FAULT device=0f:00.0 domain=0x0000 address=0x00000000000ae640 flags=0x0070]
>> Feb 12 10:47:15 harley kernel: AMD-Vi: Event logged [IO_PAGE_FAULT device=0f:00.0 domain=0x0000 address=0x00000000000ae660 flags=0x0070]
>> Feb 12 10:47:15 harley kernel: AMD-Vi: Event logged [IO_PAGE_FAULT device=0f:00.0 domain=0x0000 address=0x00000000000ae670 flags=0x0070]
>> Feb 12 10:47:27 harley kernel: ------------[ cut here ]------------
>> Feb 12 10:47:27 harley kernel: WARNING: CPU: 3 PID: 0 at drivers/iommu/amd_iommu.c:2637 dma_ops_domain_unmap.part.13+0x65/0x70()
>
> This warning indicates that some driver is unmapping a dma range that
> was not mapped previously (meaning that a pte in the io-page-tables is
> zeroed out).
> The reason for this (and the IO_PAGE_FAULTs) you see are almost
> certainly because some driver does not use the DMA-API correctly.
>
>

I wonder what driver that could be. It certainly isn't the one that I 
just unloaded
as it for sure has not done anything dma realated. I'm pretty sure I 
uninstalled all
our other drivers but will go back and verify.

Thanks
Mark