Resolve Leap Second Issues in Real-time (RT) Products
Environment
- Red Hat Enterprise Linux for Real Time (RHEL-RT)
- Red Hat Enterprise MRG Realtime (MRG-RT)
Resolution
For the primary documentation on leap seconds, including a list of known issues, see Resolve Leap Second Issues in Red Hat Enterprise Linux. Please consult this article for all non-RT kernel packages for your systems.
Red Hat Enterprise Linux for Real Time (RHEL-RT)
There are no known issues on user-space packages provided by the RHEL-RT. As RHEL-RT is a layered product on RHEL7, users must check for RHEL7 fixes for RHEL7 provided user-space packages. For more information, see Resolve Leap Second Issues in Red Hat Enterprise Linux.
The kernel-rt provided by RHEL-RT is compatible with the RHEL7 kernel. Hence, RHEL-RT users can use RHEL7 kernel information to check for leap seconds related bugs. For more information, see Resolve Leap Second Issues in Red Hat Enterprise Linux.
Red Hat Enterprise MRG Realtime (MRG-RT)
There are no known issues on user-space packages provided by the MRG-RT. As MRG-RT is a layered product on RHEL6, users must check for RHEL6 fixes for RHEL6 provided packages. For more information, see Resolve Leap Second Issues in Red Hat Enterprise Linux.
Since the change in the MRG-RT's kernel-rt version for 3.10.0-x, the kernel-rt for MRG-RT is compatible with RHEL7 kernel fixes/bug level. For these kernels, RHEL7 kernel information can be used as a reference. For more information, see Resolve Leap Second Issues in Red Hat Enterprise Linux.
Older versions
Both MRG-RT and RHEL-RT do not support older kernels. Nevertheless, in the case that users would like to keep running older kernels, here are the historical knowledge problems involving kernel-rt.
MRG v2.4
kernel-rt-3.8.13-rt14.20.el6rt and above (v2.4.0 GA release) include the fixes for the following issue(s)
- Systems hang due to leap-second livelock
- Why is there high CPU usage after inserting the leap second?
You may still encounter the following issue(s)
- TAI offset is incorrect during the leap second
- Absolute Timers that Expire at Midnight UTC May Fire Early When the Leap Second is Inserted .
MRG v2.5
kernel-3.10.33-rt32.33.el6rt and above (v2.5.0 GA release) include the fixes for the following issue(s)
- Systems hang due to leap-second livelock
- Why is there high CPU usage after inserting the leap second?
You may still encounter the following issue(s)
- TAI offset is incorrect during the leap second
- Absolute Timers that Expire at Midnight UTC May Fire Early When the Leap Second is Inserted .
MRG v2.5.12
kernel-3.10.0-229.rt56.144.el6rt and above (RHSA-20150-0694) contain the fixes for the following issue(s)
- Systems hang due to leap-second livelock
- Why is there high CPU usage after inserting the leap second?
- TAI offset is incorrect during the leap second
- Absolute Timers that Expire at Midnight UTC May Fire Early When the Leap Second is Inserted.
Earlier versions
Earlier versions of MRG-RT kernels should be considered to be susceptible to issues caused by leap second insertion.
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