The MITRE CVE dictionary describes this issue as:
The microcode on AMD 16h 00h through 0Fh processors does not properly handle the interaction between locked instructions and write-combined memory types, which allows local users to cause a denial of service (system hang) via a crafted application, aka the errata 793 issue.
Find out more about CVE-2013-6885 from the
MITRE CVE dictionary dictionary and
This hardware issue is affecting certain AMD processors. Please consult your hardware vendor for any potential firmware updates providing a workaround for this issue.