[dm-devel] AMD-Vi IO_PAGE_FAULTs and ata3.00: failed command: READ FPDMA QUEUED errors since Linux 4.0

[Andreas Hartmann]

Am 08.10.2015 um 18:39 schrieb Joerg Roedel:
> On Wed, Oct 07, 2015 at 06:52:58PM +0200, Andreas Hartmann wrote:
>> To reproduce the error:
>> First I mounted /daten2, afterwards /raid/mt, which produces the errors.
>> The ssd mounts have been already active (during boot by fstab).
>
> Okay, I spent the day on that problem, and managed to reproduce it here
> on one of my AMD IOMMU boxes. I wasn't an easy journey, as I can only
> reproduce it if I setup the crypto partition and everything above that
> (like mounting the lvm volumes) _after_ the system has finished booting.
> If everything is setup during system boot it works fine and I don't see
> any IO_PAGE_FAULTS.

Thank you very much for spending so much of your time to reproduce the 
problem!

> I also tried kernel v4.3-rc4 first, to have it tested with a
> self-compiled kernel. It didn't show up there, so I built a 4.1.0, where
> it showed up again. Something seems to have fixed the issue in the
> latest kernels.
>
> So I looked a little bit around at the commits that were merged into the
> respective parts involved here, and found this one:
>
> 	586b286 dm crypt: constrain crypt device's max_segment_size to PAGE_SIZE
 >
> The problem fixed with this commit looks quite similar to what you have
> seen (execpt that there was no IOMMU involved). So I cherry-picked that
> commit on 4.1.0 and tested that. The problem was gone.

That's true - I already knew this patch and tested it some weeks ago - 
unfortunately it doesn't fix the problem here.

To be really sure, I just retested it now again. I couldn't see any 
IO_PAGE_FAULTS errors today (unfortunately I can't remember anymore if I 
didn't see them too a few weeks ago) - but the ata errors remain. 
Therefore, this patch isn't a solution for the problem I encounter here.

> So it looks like it was a dm-crypt issue, the patch went into v4.3-rc3,
> either this kernel of rc4 should fix the problem for you too. Can you
> please verify this is fixed for you too with v4.3-rc4?

As I already wrote, I even couldn't see the problem with v4.3-rc2 any 
more (as far as I was able to test because of the other problem). I have 
to do some more tests now with this kernel to be really sure.


Kind regards,
Andreas