Bug ID 536757: BIG-IP VE may restart tmm if descheduled by hypervisor for extended periods

Last Modified: Nov 23, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP All(all modules)

Known Affected Versions:
12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3,,,,,,,, 12.1.4,, 12.1.5,,, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,,,, 15.0.0, 15.0.1,,,,, 15.1.0,,,,,, 15.1.1, 15.1.2

Opened: Jul 30, 2015
Severity: 2-Critical
Related AskF5 Article:


BIG-IP Virtual Edition (VE) configuration may restart the tmm process if it is descheduled for 10 seconds or more. This generally happens only on oversubscribed systems.


The tmm potentially restarts due to an ABORT signal. This does not always happen, depending upon what happens to run first (tmm or sod) when the BIG-IP system gets a chance to run. Traffic disrupted while tmm restarts.


-- Overprovision resources on a hypervisor without any CPU reservations for a BIG-IP system. -- Cause enough work to happen where the BIG-IP system cannot be scheduled to run for 10 seconds.


You can use either of the following workarounds: -- Reserve ample CPU resources to guarantee that tmm gets an opportunity to touch its watchdog within 10 seconds. -- Do not provision enough jobs on a hypervisor host such that the BIG-IP system is not allotted sufficient CPU cycles.

Fix Information


Behavior Change