Re: hpsa driver bug crack kernel down!

[Baoquan He <bhe@redhat.com>]

On 04/10/14 at 04:34pm, Jiang Liu wrote:
> Hi Baoquan,
> 	Could you please help to give output of "lspci -vvvv"?
> Is device "hpsa 0000:03:00.0" a legacy PCI device(non-PCIe)?
> It may have relationship with IOMMU driver.
> Thanks!
> Gerry

Well, the machine bug was reported on is a AMD machine, and it doesn't
have the IOMMU problem. David saw there are some DMAR errors, it should
be a intel machine which use the VT-d.

> 
> On 2014/4/10 12:03, Bjorn Helgaas wrote:
> > [+cc Joerg, iommu list]
> > 
> > On Wed, Apr 9, 2014 at 6:19 PM, Davidlohr Bueso <davidlohr@hp.com> wrote:
> >> On Wed, 2014-04-09 at 16:50 -0700, James Bottomley wrote:
> >>> On Wed, 2014-04-09 at 16:40 -0700, Davidlohr Bueso wrote:
> >>>> On Wed, 2014-04-09 at 16:10 -0700, James Bottomley wrote:
> >>>>> On Wed, 2014-04-09 at 16:08 -0700, James Bottomley wrote:
> >>>>>> [+linux-scsi]
> >>>>>> On Wed, 2014-04-09 at 15:49 -0700, Davidlohr Bueso wrote:
> >>>>>>> On Wed, 2014-04-09 at 10:39 +0800, Baoquan He wrote:
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>> The kernel is 3.14.0+ which is pulled just now.
> >>>>>>>
> >>>>>>> Cc'ing more people.
> >>>>>>>
> >>>>>>> While the hpsa driver appears to be involved in some way, I'm sure if
> >>>>>>> this is a related issue, but as of today's pull I'm getting another
> >>>>>>> problem that causes my DL980 not to come up.
> >>>>>>>
> >>>>>>> *Massive* amounts of:
> >>>>>>>
> >>>>>>> DMAR:[fault reason 02] Present bit in context entry is clear
> >>>>>>> dmar: DRHD: handling fault status reg 602
> >>>>>>> dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr 7f61e000
> >>>>>>>
> >>>>>>> Then:
> >>>>>>>
> >>>>>>> hpsa 0000:03:00.0: Controller lockup detected: 0xffff0000
> >>>>>>> ...
> >>>>>>> Workqueue: events hpsa_monitor_ctlr_worker [hpsa]
> >>>>>>> ...
> >>>>>>>
> >>>>>>> Screenshot of the actual LOCKUP:
> >>>>>>> http://stgolabs.net/hpsa-hard-lockup-3.14+.png
> >>>>>>>
> >>>>>>> While I haven't bisected, things worked fine until at least until commit
> >>>>>>> 39de65aa2c3e (April 2nd).
> >>>>>>>
> >>>>>>> Any ideas?
> >>>>>>
> >>>>>> Well, it's either a DMA remapping issue or a hpsa one.  Your assertion
> >>>>>> that everything worked fine until 39de65aa2c3e would tend to vindicate
> >>>>>> hpsa,
> >>>>
> >>>> Hmm here you mean DMA, right?
> >>>
> >>> No, it vindicates the hpsa changes ... they don't seem to be causing
> >>> problems until something goes wrong with dma remapping.
> >>>
> >>>>> because all the hpsa changes went in before that under
> >>>>> Missing crucial info:
> >>>>>
> >>>>> commit 1a0b6abaea78f73d9bc0a2f6df2d9e4c917cade1
> >>>>>
> >>>>>> Merge: 3e75c6d b2bff6c
> >>>>>> Author: Linus Torvalds <torvalds@linux-foundation.org>
> >>>>>> Date:   Tue Apr 1 18:49:04 2014 -0700
> >>>>>>
> >>>>>>     Merge tag 'scsi-misc' of
> >>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
> >>>>>>
> >>>>>> can you revalidate that this commit works OK just to make sure?
> >>>>
> >>>> Ok so I don't see those DMA messages and system starts just fine. I'm
> >>>> thinking perhaps something broke after the IO mmu stuff in commit
> >>>> 3f583bc21977a608908b83d03ee2250426a5695c... could this be indirectly
> >>>> causing the CPU stalls and just blame hpsa in the path as a side effect?
> >>>>
> >>>> /me goes out to try the commit.
> >>>
> >>> That's my guess.  The DMAR messages are DMA remapping issues caused in
> >>> the IOMMU.  If I had to guess, I'd say the DMAR fault message is
> >>> indicating the IOMMU is calling for a mapping address before it can
> >>> satisfy the driver read request, which is causing the hang apparently in
> >>> the hpsa driver.
> >>>
> >>> I've added linux-pci to the cc; I think they deal with iommu issues on
> >>> x86.
> >>
> >> So that merge commit appears to be the culprit, I see both the DMA
> >> messages and the lockup blaming hpsa...
> > 
> > My understanding so far (please correct me if I'm wrong):
> > 
> > 39de65aa2c3e OK ("Merge branch 'i2c/for-next'")
> > 1a0b6abaea78 OK ("Merge tag 'scsi-misc'")
> > 3f583bc21977 BAD ("Merge tag 'iommu-updates-v3.15'")
> > --
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