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

[Mikulas Patocka]

On Sun, 2 Aug 2015, Andreas Hartmann wrote:

> On 08/01/2015 at 04:20 PM Andreas Hartmann wrote:
> > On 07/28/2015 at 09:29 PM, Mike Snitzer wrote:
> > [...]
> >> Mikulas was saying to biect what is causing ATA to fail.
> > 
> > Some good news and some bad news. The good news first:
> > 
> > Your patchset
> > 
> > f3396c58fd8442850e759843457d78b6ec3a9589,
> > cf2f1abfbd0dba701f7f16ef619e4d2485de3366,
> > 7145c241a1bf2841952c3e297c4080b357b3e52d,
> > 94f5e0243c48aa01441c987743dc468e2d6eaca2,
> > dc2676210c425ee8e5cb1bec5bc84d004ddf4179,
> > 0f5d8e6ee758f7023e4353cca75d785b2d4f6abe,
> > b3c5fd3052492f1b8d060799d4f18be5a5438add
> > 
> > seems to work fine w/ 3.18.19 !!
> > 
> > Why did I test it with 3.18.x now? Because I suddenly got two ata errors
> > (ata1 and ata2) with clean 3.19.8 (w/o the AMD-Vi IO_PAGE_FAULTs) during
> > normal operation. This means: 3.19 must already be broken, too.
> > 
> > Therefore, I applied your patchset to 3.18.x and it seems to work like a
> > charme - I don't get any AMD-Vi IO_PAGE_FAULTs on boot and no ata errors
> > (until now).
> > 
> > 
> > Next I did: I tried to bisect between 3.18 and 3.19 with your patchset
> > applied, because w/ this patchset applied, the problem can be seen
> > easily and directly on boot. Unfortunately, this does work only a few
> > git bisect rounds until I got stuck because of interferences with your
> > extra patches applied:
> 
> [Resolved the problems written at the last post.]
> 
> Bisecting ended here:
> 
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=34b48db66e08ca1c1bc07cf305d672ac940268dc
> 
> block: remove artifical max_hw_sectors cap
> 
> 
> Removing this patch on 3.19 and 4.1 make things working again. Didn't
> test 4.0, but I think it's the same. No more AMD-Vi IO_PAGE_FAULTS  with
> that patch reverted.
> 
> 
> Please check why this patch triggers AMD-Vi IO_PAGE_FAULTS.
> 
> 
> Thanks,
> kind regards,
> Andreas Hartmann

I would submit this bug to maintainers of AMD-Vi. They understand the 
hardware, so they should tell why do large I/O requests result in 
IO_PAGE_FAULTs.

It is probably bug either in AMD-Vi driver or in hardware.

Mikulas