Bug 1035823 (CVE-2013-6885)

Summary: CVE-2013-6885 hw: AMD CPU erratum may cause core hang
Product: [Other] Security Response Reporter: Petr Matousek <pmatouse>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: agordeev, collura, dhoward, drjones, imammedo, jkurik, lwang, mrezanin, nobody, pbonzini, pholasek, plougher, rkrcmar, rvrbovsk, security-response-team
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-06-20 13:16:06 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 1035834, 1035836    
Bug Blocks: 1035806    

Description Petr Matousek 2013-11-28 14:57:09 UTC
793 Specific Combination of Writes to Write Combined Memory
Types and Locked Instructions May Cause Core Hang

Under a highly specific and detailed set of internal timing
conditions, a locked instruction may trigger a timing sequence whereby
the write to a write combined memory type is not flushed, causing the
locked instruction to stall indefinitely.

Potential Effect on System
Processor core hang.

Suggested Workaround
BIOS should set MSRC001_1020[15] = 1b.

The vulnerability is applicable only to family 16h model 00h-0fh AMD
CPUs. Non-AMD CPUs are not vulnerable.



Red Hat would like to thank the Xen project for reporting this issue. Upstream acknowledges Jan Beulich as the original reporter.

Comment 2 Petr Matousek 2013-11-28 14:58:48 UTC

This hardware issue is affecting certain AMD processors. Please consult your hardware vendor for any potential firmware updates providing a workaround for this issue.

Comment 4 Petr Matousek 2013-12-02 17:44:04 UTC
Xen issued advisory:


Comment 6 Vincent Danen 2014-02-19 21:42:10 UTC
It was noted that the previous fix was not sufficient for 32bit systems and also requires the following patch:




The advisory has further details.

External References:


Comment 7 Andrew Jones 2014-02-20 11:42:14 UTC
This shouldn't affect our backport. No additional patch needed for rhel5.

Comment 8 errata-xmlrpc 2014-03-12 18:30:18 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2014:0285 https://rhn.redhat.com/errata/RHSA-2014-0285.html