RHBA-2013:0348 - Bug Fix Advisory

Topic

Updated microcode_ctl packages that fix a bug and add various enhancements are
now available for Red Hat Enterprise Linux 6.

Description

The microcode_ctl packages provide utility code and microcode data to assist the
kernel in updating the CPU microcode at system boot time. This microcode
supports all current x86-based, Intel 64-based, and AMD64-based CPU models. It
takes advantage of the mechanism built-in to Linux that allows microcode to be
updated after system boot. When loaded, the updated microcode corrects the
behavior of various processors, as described in processor specification updates
issued by Intel and AMD for those processors.

This update fixes the following bug:

• Previously, a udev rule in /lib/udev/rules.d/89-microcode.rules allowed the

module to load more than once. On very large systems (for example, systems with
2048 or more CPUs), this could result in the system becoming unresponsive on
boot. With this update, the udev rule has been changed to ensure the module
loads only once. Very large systems now boot as expected. (BZ#740932)

This update also adds the following enhancements:

• The Intel CPU microcode file has been updated to version 20120606. (BZ#818096)
• The AMD CPU microcode file has been updated to version 20120910. (BZ#867078)

All users of microcode_ctl are advised to upgrade to these updated packages,
which fix this bug and add these enhancements. Note: a system reboot is
necessary for this update to take effect.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386

Fixes

• BZ - 867078 - RHEL 6.4:Please include AMD microcode for processor families 10h-14h(microcode_amd.bin) and 15h(microcode_amd_fam15h.bin)

CVEs

(none)

References

(none)