RHBA-2016:2883 - Bug Fix Advisory

Topic

Updated kernel-rt packages that fix several bugs are now available for Red Hat Enterprise Linux 7.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

The kernel-rt packages have been upgraded to the 3.10.0-514.2.1 source tree, which provides a number of bug fixes over the previous version. (BZ#1388526)

This update also fixes the following bugs:

• Previously, the leapsec_timer (LTP) test in some cases failed, because the hrtimer subsystem expired earlier than expected. With this update, the timekeeping_update() function is executed on the shadow timekeeper prior to copying the full state over to the real timekeeper, and LTP test now passes every timekeeper. (BZ#1396105)
• Previously, the use of the synchronized_rcu_expedited() kernel function might delay the execution of some high-priority realtime operations. This caused latency spikes in the system. With this update, the kernel code has been modified to not allow calling this functio on a realtime kernel. As a result, the potential latency spikes have been eliminated. (BZ#1388528)

Users of kernel-rt 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.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for Real Time 7 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 7 x86_64
• Red Hat Enterprise Linux for Real Time for x86_64 - Extended Life Cycle Support 7 x86_64

Fixes

• BZ - 1388526 - kernel-rt: update to the RHEL7.3.z batch#1 source tree [rt-7.3.z]
• BZ - 1388528 - KVM-RT: halting and starting guests cause latency spikes [rhel-rt-7.3.z]

CVEs

(none)

References

(none)