Re: AMD IOMMU causing filesystem corruption

[Joerg Roedel]

Hi Samuel,

On Mon, Apr 03, 2017 at 01:38:08PM -0700, Samuel Sieb wrote:
> I filed a bug in bugzilla, but I wasn't sure what category to put it
> in, so I suspect I ended up picking one that doesn't get looked at
> much.
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=195051
> 
> The issue is that on a specific Acer laptop with a dual-core A9, if
> I don't disable the IOMMU using iommu=off, it has immediate and
> rapidly fatal filesystem corruption by the time a user logs into the
> desktop. What led me to try that was at one point I noticed an error
> message about the iommu in the logs.  However, I did not have a
> chance to save that due to the corruption obliterating the log
> files.

You have a system based on the AMD Stoney platform, on which the PCI-ATS
feature of the GPU is broken, as we recently found out.

Can you please test whether the attached patch fixes the issue on your
machine?