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SubjectRe: oops in pci_acs_path_enabled
On 8/3/12 2:21 PM, Alex Williamson wrote:
> On Fri, 2012-08-03 at 11:39 -0600, David Ahern wrote:
>> Hi Alex:
>>
>> Hitting an oops with 3.6-rc1. Backtrace from console attached. git blame
>> for the top function points to ad805758.
>
> Hey David,
>
> Hmm, what's special about your system? I've got an 82576 here and the
> same path works fine. Any way you can get the top of the oops message?
> Thanks,
>
> Alex
>

Dell R410 I believe. pair of 5620 processors. 3 overlapping screen shots
attached. objdump on pci.o suggests the pdev is NULL:

/opt/sw/ahern/kernels/kernel.git/drivers/pci/pci.c:2454

ret = pci_dev_specific_acs_enabled(pdev, acs_flags);
if (ret >= 0)
return ret > 0;
if (!pci_is_pcie(pdev))
408a: 41 80 7c 24 4a 00 cmpb $0x0,0x4a(%r12)
4090: 74 e8 je 407a <pci_acs_enabled+0x2a>

Perhaps this bug explains the larger the issue which is that device
passthrough in 3.6-rc1 (0d7614f) is broken for me -- config field for
the PCI device does not exist. e.g.,

pcilib: Cannot open /sys/bus/pci/devices/0000:06:10.0/config
lspci: Unable to read the standard configuration space header of device
0000:06:10.0
pcilib: Cannot open /sys/bus/pci/devices/0000:06:10.0/config
lspci: Unable to read the standard configuration space header of device
0000:06:10.0
failed to find vendor-product id for PCI id "06:10.0"
Failed to claim PCI device 06:10.0
git bisect points to:

783f157bc5a7fa30ee17b4099b27146bd1b68af4 is the first bad commit
commit 783f157bc5a7fa30ee17b4099b27146bd1b68af4
Author: Alex Williamson <alex.williamson@redhat.com>
Date: Wed May 30 14:19:43 2012 -0600

intel-iommu: Make use of DMA quirks and ACS checks in IOMMU groups

Work around broken devices and adhere to ACS support when determining
IOMMU grouping.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

:040000 040000 83890398dabbf225fd0f5b3c8c3713a75b3fb5e1
b674ce2ecb315393a8c6c1ac98b3796d5ba09708 M drivers

I triggered the oops in a number of the bisect points as well -- in
those cases the machine had to be power cycled.

David

[unhandled content-type:image/png][unhandled content-type:image/png][unhandled content-type:image/png]
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