Bug ID 537034: PEM: CPU spike seen when iRule tries to update nonexistent sessions.

Last Modified: May 14, 2019

Bug Tracker

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

Known Affected Versions:
11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 12.0.0

Fixed In:
12.1.0, 12.0.0 HF1, 11.6.0 HF6

Opened: Aug 01, 2015
Severity: 3-Major
Related AskF5 Article:


CPU spikes and remains high, eventually leading to TMM core.


CPU spike. Traffic disrupted while tmm restarts.


iRule is used to update a session with policies for a session that does not exist.


Make sure the session exists if you plan to use iRules to update sessions with policies.

Fix Information

CPU spike are no longer seen, even if iRule tries to update nonexistent sessions.

Behavior Change