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

[Andreas Hartmann <andihartmann@freenet.de>]

On 10/08/2015 at 08:21 PM, Andreas Hartmann wrote:
> 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.

I now tested w/ v4.3-rc4. I couldn't see any IO_PAGE_FAULTS but the ata
errors remain. The ata errors can be easily activated by copying a large
file (> 4 GB) from one partition on the raid to another partition on the
raid.



Thanks,
Andreas