Re: Kernel Oops: iommu related?

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

On 02/12/2015 02:37 PM, Mark Hounschell wrote:
> On 02/12/2015 01:25 PM, Mark Hounschell wrote:
>> 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.
>>
>
> I've cleaned the machine of all our drivers and also the nvidia driver.
> If the problem is as you say, it is an in-kernel driver. I've attached a
> dmesg taken after it started. I used the dgap driver from the staging
> directory to unload and trigger this as I have one. That driver does NO
> dma. I know because I'm one of the maintainers and have done lots of
> work on it.
>

There was a dmesg attached to my previous email BTW

Mark