Bug 834583

Summary: kernel-rt-3.2.20-rt32.44.el6rt.x86_64 floods the console with "DMAR [fault reason 02] Present bit in context entry is clear"
Product: Red Hat Enterprise MRG Reporter: David Sommerseth <davids>
Component: realtime-kernelAssignee: John Kacur <jkacur>
Status: CLOSED ERRATA QA Contact: David Sommerseth <davids>
Severity: high Docs Contact:
Priority: high    
Version: 2.2CC: bhu, iboverma, jkastner, lgoncalv, ovasik, williams
Target Milestone: 2.2   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
* Cause: intel-iommu.ko driver has interrupt handling problems with some Sandy Bridge hardware * Consequence: Console gets flooded at boot with DMAR interrupt messages * Fix: default intel-iommu to off and allow loading with kernel command line 'intel_iommu=on' * Result: No DMAR interrupt message flood
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-09-19 18:04:09 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description David Sommerseth 2012-06-22 13:57:51 UTC
Booting kernel-rt-3.2.20-rt32.44 on some servers floods the console with messages like this:

----------------------------------------------
[01:0DRHD: handling fault status reg 2 
DMAR:[DMA Rt entry is clear 
<3>DRHD: handlinentry is clear 
DRHD: handling fault status reg 2 
DMAR:[DMA Read] Request device [01:00.2] fault addr edfe4000  
DMAR:[fault reason 02] Present bit in context entry is clear 
DRHD: handling fault status reg 2 
DMAR:[DMA Read] Request device [01:00.2] fault addr edfe4000  
DMAR:[fault reason 02] Present bit in context entry is clear 
DRHD: handling fault status reg 2 
----------------------------------------------

Comment 3 David Sommerseth 2012-06-22 14:24:47 UTC
A common issue a couple of boxes is this warning:

------------------------------------------------------------------
DMAR: DRHD base: 0x000000fed90000 flags: 0x1 
IOMMU fed90000: ver 1:0 cap c9008020660262 ecap f010da 
DMAR: RMRR base: 0x000000f1ffd000 end: 0x000000f1ffffff 
DMAR: No ATSR found 
IOAPIC id 8 under DRHD base 0xfed90000 
Your BIOS has requested that x2apic be disabled. 
This will leave your machine vulnerable to irq-injection attacks. 
Use 'intremap=no_x2apic_optout' to override BIOS request. 
Enabled IRQ remapping in x2apic mode 
Enabling x2apic 
Enabled x2apic
------------------------------------------------------------------

Comment 4 Beth Uptagrafft 2012-06-29 20:04:43 UTC
Notes from David:
>  btw ... the DMAR issue ... that's present on upstream 3.2.20 kernel as well ... that's the source from kernel.org without PREEMPT_RT patch but with our config

> and intel_iommu=off "removes" this issue ... so we have something to poke further on

Comment 5 Clark Williams 2012-07-05 16:36:06 UTC
Looking at beaker test run on system intel-s3ea2-04.rhts.eng.bos.redhat.com, looks like this might be a system affected by the DMAR issue. Console log:

http://beaker-archive.app.eng.bos.redhat.com/beaker-logs/2012/06/2555/255532/544410/console.log

Comment 7 Clark Williams 2012-07-18 19:37:56 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
* Cause:  intel-iommu.ko driver has interrupt handling problems with some Sandy Bridge hardware
* Consequence: Console gets flooded at boot with DMAR interrupt messages
* Fix: default intel-iommu to off and allow loading with kernel command line 'intel_iommu=on'
* Result: No DMAR interrupt message flood

Comment 8 Beth Uptagrafft 2012-07-18 20:02:31 UTC
from the changelog of 3.2.22-rt34.46, 
- [mrg] turned off INTEL_IOMMU_DEFAULT_ON (DMAR flood issue) [BZ# 834583]

Comment 13 errata-xmlrpc 2012-09-19 18:04:09 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2012-1282.html