RHBA-2014:1504 - Bug Fix Advisory

Topic

Updated irqbalance packages that fix several bugs are now available for Red Hat
Enterprise Linux 6.

Description

The irqbalance packages provide a daemon that evenly distributes the interrupt
request (IRQ) load across multiple CPUs for enhanced performance.

This update fixes the following bugs:

• Previously, the irqbalance daemon did not consider the NUMA node assignment

for an interrupt request (IRQ) for the banned CPU set. Consequently, irqbalance
set the affinity incorrectly when the IRQBALANCE_BANNED_IRQS variable was set to
a single CPU. In addition, IRQs could be assigned to a node that had no eligible
CPUs. Node assignment has been restricted to nodes that have eligible CPUs as
defined by the unbanned_cpus bitmask, thus fixing the bug. As a result,
irqbalance now sets the affinity properly, and IRQs are assigned to the
respective nodes correctly. (BZ#1039178)

• Prior to this update, the dependency of the irqbalance daemon was set

incorrectly referring to a wrong kernel version. As a consequence, irqbalance
could not balance IRQs on NUMA systems. With this update, the dependency has
been fixed, and IRQs are now balanced correctly on NUMA systems. Note that users
of irqbalance packages have to update the kernel to 2.6.32-358.2.1 or later in
order to use the irqbalance daemon in the correct manner. (BZ#987801)

• Prior to this update, irqbalance could not accurately determine the NUMA node

it was local to or the device to which an IRQ was sent. The kernel affinity_hint
values were created to work around this issue. With this update, irqbalance is
now capable of parsing all information about an IRQ provided by the sysfs()
function. IRQ balancing now works correctly, and the affinity_hint values are
now ignored by default not to distort the irqbalance functionality. (BZ#1079109)

Users of irqbalance are advised to upgrade to these updated packages, which fix
these bugs.

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/site/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• 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 6 i386
• Red Hat Enterprise Linux Desktop 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 - 878001 - NULL dereferencing and memory leaks
• BZ - 1052166 - irqbalance exits early when cpus are restricted to the one cache domain
• BZ - 1079109 - irqbalance oneshot not working with ixgbe

CVEs

(none)

References

(none)