Issued:

2012-08-23

Updated:

2012-08-23

RHBA-2012:1199 - kernel bug fix update

Synopsis

kernel bug fix update

Type/Severity

Bug Fix Advisory

Topic

Updated kernel packages that fix two bugs are now available for Red Hat Enterprise Linux 6.

Description

The kernel packages contain the Linux kernel, the core of any Linux operating system.

When an NTP server asserts the STA_INS flag (Leap Second Insert), the kernel starts an hrtimer (high-resolution timer) with a countdown clock. This hrtimer expires at end of the current month, midnight UTC, and inserts a second into the kernel timekeeping structures. A scheduled leap second occurred on June 30 2012 midnight UTC.

This update fixes the following bugs:

• Previously in the kernel, when the leap second hrtimer was started, it was possible that the kernel livelocked on the xtime_lock variable. This update fixes the problem by using a mixture of separate subsystem locks (timekeeping and ntp) and removing the xtime_lock variable, thus avoiding the livelock scenarios that could occur in the kernel. (BZ#840950)

• After the leap second was inserted, applications calling system calls that used futexes consumed almost 100% of available CPU time. This occurred because the kernel's timekeeping structure update did not properly update these futexes. The futexes repeatedly expired, re-armed, and then expired immediately again. This update fixes the problem by properly updating the futex expiration times by calling the clock_was_set_delayed() function, an interrupt-safe method of the clock_was_set() function. (BZ#847366)

All users are advised to upgrade to these updated packages, which fix these bugs. The system must be rebooted 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

Updated Packages

• perf-debuginfo-2.6.32-279.5.2.el6.s390x.rpm
• kernel-debuginfo-2.6.32-279.5.2.el6.ppc64.rpm
• python-perf-debuginfo-2.6.32-279.5.2.el6.s390x.rpm
• python-perf-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-headers-2.6.32-279.5.2.el6.i686.rpm
• kernel-devel-2.6.32-279.5.2.el6.i686.rpm
• kernel-debug-2.6.32-279.5.2.el6.i686.rpm
• kernel-debug-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-bootwrapper-2.6.32-279.5.2.el6.ppc64.rpm
• python-perf-debuginfo-2.6.32-279.5.2.el6.x86_64.rpm
• perf-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-firmware-2.6.32-279.5.2.el6.noarch.rpm
• kernel-headers-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-debuginfo-common-s390x-2.6.32-279.5.2.el6.s390x.rpm
• kernel-2.6.32-279.5.2.el6.s390x.rpm
• kernel-kdump-2.6.32-279.5.2.el6.s390x.rpm
• kernel-debug-devel-2.6.32-279.5.2.el6.s390x.rpm
• kernel-devel-2.6.32-279.5.2.el6.s390x.rpm
• perf-2.6.32-279.5.2.el6.s390x.rpm
• perf-debuginfo-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-debug-devel-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-debug-debuginfo-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-debug-debuginfo-2.6.32-279.5.2.el6.i686.rpm
• kernel-debug-debuginfo-2.6.32-279.5.2.el6.ppc64.rpm
• perf-2.6.32-279.5.2.el6.i686.rpm
• kernel-debuginfo-common-x86_64-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-headers-2.6.32-279.5.2.el6.s390x.rpm
• perf-debuginfo-2.6.32-279.5.2.el6.i686.rpm
• kernel-devel-2.6.32-279.5.2.el6.x86_64.rpm
• python-perf-debuginfo-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-debug-2.6.32-279.5.2.el6.s390x.rpm
• kernel-debug-debuginfo-2.6.32-279.5.2.el6.s390x.rpm
• kernel-debuginfo-2.6.32-279.5.2.el6.i686.rpm
• kernel-debug-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-kdump-debuginfo-2.6.32-279.5.2.el6.s390x.rpm
• python-perf-2.6.32-279.5.2.el6.s390x.rpm
• kernel-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-debuginfo-common-i686-2.6.32-279.5.2.el6.i686.rpm
• kernel-debug-devel-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-kdump-devel-2.6.32-279.5.2.el6.s390x.rpm
• python-perf-debuginfo-2.6.32-279.5.2.el6.i686.rpm
• kernel-doc-2.6.32-279.5.2.el6.noarch.rpm
• perf-debuginfo-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-debuginfo-2.6.32-279.5.2.el6.s390x.rpm
• python-perf-2.6.32-279.5.2.el6.i686.rpm
• kernel-debuginfo-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-2.6.32-279.5.2.el6.i686.rpm
• kernel-debug-devel-2.6.32-279.5.2.el6.i686.rpm
• python-perf-2.6.32-279.5.2.el6.ppc64.rpm
• perf-2.6.32-279.5.2.el6.x86_64.rpm
• kernel-debuginfo-common-ppc64-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-headers-2.6.32-279.5.2.el6.ppc64.rpm
• kernel-2.6.32-279.5.2.el6.src.rpm
• kernel-devel-2.6.32-279.5.2.el6.ppc64.rpm

Fixes

• This content is not included.BZ - 840950

CVEs

(none)

References

(none)

Additional information

• The Red Hat security contact is This content is not included.secalert@redhat.com. More contact details at https://access.redhat.com/security/team/contact/.
• Offline Security Data data is available for integration with other systems. See Offline Security Data API to get started.