Re: IOMMU+DMAR causing NMIs-s

From: Linda Knippers
Date: Wed Jul 13 2016 - 11:48:55 EST

On 7/13/2016 10:48 AM, Alex Williamson wrote:
> On Wed, 13 Jul 2016 12:18:59 +0200
> Joerg Roedel <joro@xxxxxxxxxx> wrote:
>> On Wed, Jul 13, 2016 at 12:58:24PM +0300, Meelis Roos wrote:
>>>>> Just got when playing with
>>>>> BIOS settings (disabling NUMA). It is the first time I see at least some
>>>>> info in NMI decode.
>>>> This looks interesting. Can you please post output of 'lspci -vvv' and
>>>> 'lspci -t'?
>>> Here.
>> Thanks. So device 00:1e.0 is a PCI-bridge which has some 32-bit
>> PCI-devices behind it. One of these devices tries to read address
>> 0xb000, which is blocked by the IOMMU and causes the fault seen in the
>> screen-shot. The fault also causes a PCI-error which is then reported
>> through the NMI, causing your kernel panic.
>> So the 32bit PCI devices behind the bridge are:
>> 01:03.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] ES1000 (rev 02) (prog-if 00 [VGA controller])
>> 01:04.0 System peripheral: Compaq Computer Corporation Integrated Lights Out Controller (rev 03)
>> 01:04.2 System peripheral: Compaq Computer Corporation Integrated Lights Out Processor (rev 03)
>> 01:04.4 USB controller: Hewlett-Packard Company Integrated Lights-Out Standard Virtual USB Controller (prog-if 00 [UHCI])
>> 01:04.6 IPMI SMIC interface: Hewlett-Packard Company Integrated Lights-Out Standard KCS Interface (prog-if 01)
>> Can you try to disable this 'Lights Out' processor? Maybe it is causing
>> the issues. On the other side, the radeon driver for the ATI card is
>> also know for causing faults from time to time. Can you capture the
>> kernel messages right before a crash too?
> IIRC, blacklisting the hpwdt module can defuse those NMIs and might
> help us see more of the actual DMAR faults. Blacklist in modprobe.d
> and rebuild initrd. Thanks,
> Alex
> PS - never assume BIOS release notes are actually complete

I agree. I'd do the BIOS update and also make sure the iLO FW is current.

-- ljk
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