Bug ID 521408: Incorrect configuration in BigTCP Virtual servers can lead to TMM core

Last Modified: Apr 10, 2019

Bug Tracker

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

Known Affected Versions:
11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5

Fixed In:
12.0.0, 11.6.0 HF6, 11.5.3 HF2

Opened: May 05, 2015
Severity: 3-Major


An incorrect configuration on an irule associated to a BigTCP virtual server can lead to TMM to core.


Traffic disrupted while tmm restarts.


The following circumstances are needed: - BigTCP Virtual server - FastL4 profile with syncookies enabled. - Invalid iRule that will fail to execute, on LB_FAILED - Syncookie currently activated in that moment.


Correct or remove the irule event and coring will no longer occur.

Fix Information

TMM now correctly handles the specific scenario to no longer core.

Behavior Change