Oracle Legal Notices
Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners.
Intel and Intel Xeon are trademarks or registered trademarks of Intel Corporation. All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. AMD, Opteron, the AMD logo, and the AMD Opteron logo are trademarks or registered trademarks of Advanced Micro Devices. UNIX is a registered trademark of The Open Group.
License Restrictions Warranty/Consequential Damages Disclaimer
This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.
The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.
Restricted Rights Notice
If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:
U.S. GOVERNMENT END USERS: Oracle programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, delivered to U.S. Government end users are "commercial computer software" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, use, duplication, disclosure, modification, and adaptation of the programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, shall be subject to license terms and license restrictions applicable to the programs. No other rights are granted to the U.S. Government.
Hazardous Applications Notice
This software or hardware is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications that may create a risk of personal injury. If you use this software or hardware in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure its safe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software or hardware in dangerous applications.
Third-Party Content, Products, and Services Disclaimer
This software or hardware and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.
Alpha and Beta Draft Documentation Notice Disclaimer
If this document is in preproduction status:
This documentation is in preproduction status and is intended for demonstration and preliminary use only. It may not be specific to the hardware on which you are using the software. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to this documentation and will not be responsible for any loss, costs, or damages incurred due to the use of this documentation.
This document contains information on Quarterly Update 3 to the Unbreakable Enterprise Kernel Release 2. This document may be updated after it is released. To check for updates to this document, and to view other Oracle documentation, refer to the Documentation section on the Oracle Technology Network (OTN) Web site:
This document is intended for users and administrators of Oracle Linux. It describes potential issues and the corresponding workarounds you may encounter while using the Unbreakable Enterprise Kernel Release 2 with Oracle Linux 5 and Oracle Linux 6. Oracle recommends that you read this document before installing or upgrading the Unbreakable Enterprise Kernel Release 2.
Document generated on: 2013-02-27 (revision: 615)
Table of Contents
The Oracle Linux Unbreakable Enterprise Kernel Release Notes provides a summary of the new features, changes, and fixed and known issues in the Unbreakable Enterprise Kernel Release 2.
This document is written for system administrators who want to use the Unbreakable Enterprise Kernel with Oracle Linux. It is assumed that readers have a general understanding of the Linux operating system.
For information about Oracle's commitment to accessibility, visit the Oracle Accessibility Program website at http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc.
Oracle customers have access to electronic support through My Oracle Support. For information, visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs if you are hearing impaired.
The latest version of this document and other documentation for this product are available at:
The following text conventions are used in this document:
Boldface type indicates graphical user interface elements associated with an action, or terms defined in text or the glossary.
Italic type indicates book titles, emphasis, or placeholder variables for which you supply particular values.
Monospace type indicates commands within a paragraph, URLs, code in examples, text that appears on the screen, or text that you enter.
Table of Contents
The Unbreakable Enterprise Kernel Release 2 (UEK R2) is Oracle's second major release of its heavily tested and optimized operating system kernel for Oracle Linux 5 and Oracle Linux 6. It is based on the mainline Linux 3.0 version 3.0.36. It contains a large number of improvements and new features that have been incorporated into mainline Linux since the first version of the Unbreakable Enterprise Kernel, which was based on Linux 2.6.32. See the initial Oracle Unbreakable Enterprise Kernel Release 2 Release Notes (https://oss.oracle.com/ol6/docs/RELEASE-NOTES-UEK2-en.html) for a detailed description of these changes.
The 2.6.39-400 release is a quarterly driver update release which also includes bug and security fixes.
The actual version number displayed by the kernel and on the RPM packages is 2.6.39. This was done to avoid potential breakage of certain low-level utilities of the Oracle Linux distribution (also known as the plumbing) that potentially cannot cope with the new 3.x version scheme. Regular Linux applications are usually not aware or affected by Linux kernel version numbers.
The code base has been aligned with mainline Linux 3.0.36.
Support for the SGI UV 2 architecture has been added.
Support for family 15H model 2 (Abu Dhabi) AMD processors has been added.
NBD, the network block device driver has been updated and enabled
The following InfiniBand hardware is supported with the Unbreakable Enterprise Kernel:
Mellanox ConnectX-2 InfiniBand Host Channel Adapters
Sun InfiniBand QDR Host Channel Adapter PCIe #375-3696
The QLogic iSCSI driver (
qla4xxx) has been updated to support
Several improvements have been incorporated into the Unbreakable Enterprise Kernel to support Xen usage:
Numerous bug fixes and performance improvements.
Added support for more than 128 GB in a PV guest.
Xen Machine Check Exception (MCE) driver added (allows you to view MCE events that the Xen hypervisor receives).
Xen Physical CPU (PCPU) driver added (allows management tools to online or offline physical CPUs in dom0).
Xen Processor Aggregator Device (PAD) added (enables configuration and control of all processors on a platform).
The Unbreakable Enterprise Kernel supports a wide range of hardware and devices. In close cooperation with hardware and storage vendors, several device drivers have been updated by Oracle.
NetXtreme II iSCSI driver (
bnx2i) updated to 18.104.22.168f.
NetXtreme II Fibre Channel over Ethernet driver (
updated to 2.2.17.
Blade Engine 2 Open-iSCSI driver (
be2iscsi) updated to
Fibre Channel HBA driver (
lpfc) updated to
ConnectX core driver (
mlx4_core) released at 1.0-ofed1.5.5
(x86_64 only). Handles low-level functions such as device initialization and
firmware commands processing, and controls resource allocation so that the
InfiniBand and Ethernet functions can share a device without interfering with each
ConnectX Ethernet driver (
mlx4_en) released at 22.214.171.124
(x86_64 only). Handles Ethernet-specific functions and plugs into the netdev
ConnectX InfiniBand driver (
mlx4_ib) released at
1.0-ofed1.5.5 (x86_64 only). Handles InfiniBand-specific functions.
Fibre Channel HBA driver (
qla2xxx) updated to
iSCSI driver (
qla4xxx) updated to 5.03.00.01.06.02-uek2. Now
NetXtreme II network adapter driver (
bnx2) updated to
NetXtreme II 10Gbps network adapter driver (
bnx2x) updated to
Converged Network Interface Card core driver (
Tigon3 Ethernet adapter driver (
tg3) updated to
Blade Engine 2 10Gbps adapter driver (
be2net) updated to
PRO/1000 PCI-Express Gigabit network adapter driver (
updated to 2.1.4-NAPI.
Gigabit Ethernet network adapter driver (
igb) updated to
10 Gigabit PCI-Express network adapter driver (
10 Gigabit Server Adapter virtual function driver (
updated to 2.6.2-NAPI. The kernel must support Single Root I/O Virtualization
NetXen Multiport 1/10 Gigabit Network adapter driver
netxen_nic) updated to 4.0.80.
1/10 GbE Converged/Intelligent Ethernet Adapter driver
qlcnic) updated to 126.96.36.199.
QLE81xx network adapter driver (
qlge) updated to
The following features included in the Unbreakable Enterprise Kernel Release 2 are still under development, but are made available for testing and evaluation purposes.
DRBD (Distributed Replicated Block Device)
A shared-nothing, synchronously replicated block device (RAID1 over network), designed to serve as a building block for high availability (HA) clusters. It requires a cluster manager (for example, pacemaker) for automatic failover.
Kernel module signing facility
Applies cryptographic signature checking to modules on module load, checking the signature against a ring of public keys compiled into the kernel. GPG is used to do the cryptographic work and determines the format of the signature and key data.
Linux Containers (lxc)
Based on the Linux Cgroups and name spaces functionality, containers allow you to
safely and securely run multiple applications or instances of an operating system on a
single host without risking them interfering with each other. Containers are lightweight
and resource-friendly, which saves both rack space and power. In order to get started
with containers, you need to install the
lxc package, which is
included in the package repository of the Unbreakable Enterprise Kernel.
Transcendent Memory (tmem for short) provides a new approach for improving the utilization of physical memory in a virtualized environment by claiming underutilized memory in a system and making it available where it is most needed. From the perspective of an operating system, tmem is fast pseudo-RAM of indeterminate and varying size that is useful primarily when real RAM is in short supply. To learn more about this technology and its use cases, see the Transcendent Memory project page at http://oss.oracle.com/projects/tmem/.
Oracle Linux maintains user-space compatibility with Red Hat Enterprise Linux, which is independent of the kernel version running underneath the operating system. Existing applications will continue to run unmodified on the Unbreakable Enterprise Kernel Release 2 and no re-certifications are needed for RHEL certified applications.
The Oracle Linux team works closely with third-party hardware and software vendors to minimize impact on interoperability during releases but in order to introduce new drivers there are instances where changes must be made. In this release, there are changes to the kernel ABI which requires third-party kernel modules on the system be recompiled. Before installing this update, verify the support status of this release with your application vendor.
This chapter describes the fixed and known issues for the Unbreakable Enterprise Kernel Release 2.
The following issues have been fixed in this update.
The legacy DNS resolver now supports the sending of NFSv4 referrals (lists of NFS
servers and exported NFS file systems) to Oracle Linux 6 clients. The user-space
component in the
nfs-utils package is distributed with Oracle Linux
6 Update 4. (Bug ID 14769650)
A bug has been fixed that caused connections to hang when running SysBench benchmarks on MySQL with the thread pool enabled. (Bug ID 16363540)
This section describes known issues in this update.
One some systems you might see ACPI-related error messages in
similar to the following:
ACPI Error: [CDW1] Namespace lookup failure, AE_NOT_FOUND ACPI Error: Method parse/execution failed [_SB_._OSC||\||] ACPI Error: Field [CDW3] at 96 exceeds Buffer [NULL] size 64 (bits)]]>
These messages, which are not fatal, are caused by bugs in the BIOS. Contact your system vendor for a BIOS update. (Bug ID 13100702)
/etc/init.d/oracleasm, with the parameter
scandisks can lead to error messages about missing devices similar to
oracleasm-read-label: Unable to open device "
device": No such file or directory
However, the device actually exists. You can ignore this error message, which is
triggered by a timing issue. Only use the
init script to start and stop
oracleasm service. All other options, such as scandisks,
createdisk, are deprecated. For these
and other administrative tasks, use
/usr/sbin/oracleasm instead. (Bug ID
When using the
bnx2x driver in a bridge, disable Transparent Packet
Aggregation (TPA) by including the statement
options bnx2x disable_tpa=1
/etc/modprobe.conf. (Bug ID 14626070)
Running btrfs filesystem balance converts a non-RAID or concatenated file system setup to RAID-0 after adding a new device. (Bug ID 13715389)
Converting an existing
ext4 root file system to
btrfs does not carry
over the associated security contexts that are stored as part of a file's extended
attributes. With SELinux enabled and set to enforcing mode, you might experience many
permission denied errors after reboot, and the system might be unbootable. To avoid
this problem, enforce automatic file system relabeling to run at bootup time. To
trigger automatic relabeling, create an empty file named
.autorelabel (for example, by using touch) in
the file system's
root directory before rebooting the system after
the initial conversion. The presence of this file instruct SELinux to recreate the
security attributes for all files on the file system. If you forget to do this and
rebooting fails, either temporarily disable SELinux completely by adding
selinux=0 to the kernel boot parameters, or disable enforcing of
the SELinux policy by adding
enforcing=0. (Bug ID 13806043)
A failing RAID1 disk might result in a kernel panic with the error kernel:
BTRFS error (device (null)) in btree_writepage_io_failed_hook:3662: \ IO failure (Error occurred while writing out btree at offset).
(Bug ID 16262571)
The btrfs subvolume get-default command lists all existing subvolumes instead of only the default subvolume. (Bug ID 13815433)
The btrfs filesystem defragment command exits with an exit code of 20 even if it succeeds. (Bug ID 13714531)
Commands such as du might show inconsistent results for file
sizes in a
btrfs file system when the number of bytes that is under
delayed allocation is changing. (Bug ID 13096268)
Btrfs has a limit of 237 hard links to a file. Attempting to create more than this
number of links results in the error
Too many links. (Bug ID
When running Oracle Linux with UEK R2, you might see error messages in
/var/log/messages similar to this
microcode: CPU0 update to revision 0x6b failed.
You can ignore this warning. You do not need to upgrade the microcode for virtual CPUs as presented to the guest. (Bug ID 12576264, 13782843)
The Unbreakable Enterprise Kernel uses the
deadline scheduler as the
default I/O scheduler. For the Red Hat Compatible Kernel, the default I/O scheduler is the
The following message might appear in
WARNING! power/level is deprecated; use power/control instead.
The USB subsystem in UEK R2 deprecates the
attribute in favor of the
power/control attribute. The
libfprint fingerprinting library triggers this warning via
udev rules that try to use the old attribute first. You can safely
ignore this warning. The setting of the appropriate power level still succeeds. (Bug ID
After upgrading to UEK R2, the NVIDIA driver upgrade script does not correctly blacklist
the Nouveau kernel driver. To blacklist the driver, append
nouveau.modeset=0 to the kernel boot parameters in
For the Unbreakable Enterprise Kernel,
set by default. For the Red Hat Compatible Kernel,
kernel.sched_compat_yield=0 is used by default.
A message similar to the following might be recorded in
/var/log/messages at boot
pid/oom_adj is deprecated, please use /proc/
udev process uses the deprecated
interface to prevent it from being killed if the system runs short of memory. You can safely
ignore the message as the action still succeeds. To prevent the message from occurring,
install the package
or higher for Oracle Linux 6, or
udev-095-188.8.131.52.el5. or higher
for Oracle Linux 5. (Bug ID 13655071 and 13712009)
When booting UEK R2 as a 32-bit PVHVM guest, you can safely ignore the following kernel message:
register_vcpu_info failed: err=-38
(Bug ID 13713774)
The Unbreakable Enterprise Kernel Release 2 can be installed on Oracle Linux 5 Update 8 or newer, as well as Oracle Linux 6 Update 2 or newer, both running either the Red Hat compatible kernel or a previous version of the Unbreakable Enterprise Kernel. If you are still running an older version of Oracle Linux, first update your system to the latest available update release.
The kernel images are available as binary RPM packages from dedicated channels on Oracle's Unbreakable Linux Network as well as the public yum repository. Four channels are available:
Oracle Linux 5 (x86):
Oracle Linux 5 (x86_64):
Oracle Linux 6 (x86):
Oracle Linux 6 (x86_64):
Existing Oracle Linux 5 or Oracle Linux 6 installations can be upgraded to UEK R2 by
enabling the appropriate
UEK_latest channel and running yum
update. The channel is automatically enabled for freshly installed Oracle Linux 6
Update 3 systems that shipped with the 2.6.39-200 kernel version of UEK R2.
For detailed instructions on how to download and install the Unbreakable Enterprise Kernel on Oracle Linux see the Getting Started with the Unbreakable Enterprise Kernel for Oracle Linux document on the Oracle Technology Network (OTN) at http://www.oracle.com/technetwork/articles/servers-storage-admin/uek-rel2-getting-started-1555632.html.
If you have questions regarding configuring or using yum to install updates, refer to the Oracle Linux Administrator's Solutions Guide at http://docs.oracle.com/cd/E37670_01/index.html.
The kernel's source code is available via a public git source code repository at http://oss.oracle.com/git/?p=linux-uek-2.6.39.git.