Bug ID 479183: Unexpected iSession tunnel state transition causes TMM to restart.

Last Modified: Aug 19, 2026

Affected Product(s):
BIG-IP AAM, WOM(all modules)

Known Affected Versions:
11.5.1, 11.5.1 hf1, 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, 11.5.1 hf10, 11.5.1 hf11, 11.5.2, 11.5.2 hf1, 11.5.3, 11.5.3 hf1, 11.5.3 hf2, 11.5.4, 11.5.4 hf1, 11.5.4 hf2, 11.5.4 hf3, 11.5.4 hf4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.0 hf1, 11.6.0 hf2, 11.6.0 hf3, 11.6.0 hf4, 11.6.0 hf5, 11.6.0 hf6, 11.6.0 hf7, 11.6.0 hf8, 11.6.1, 11.6.1 hf1, 11.6.1 hf2, 11.6.2, 11.6.2 hf1

Fixed In:
12.0.0, 11.6.3

Opened: Sep 12, 2014

Severity: 3-Major

Related Article: K01749002

Symptoms

A TMM process cores due to a 'valid event' assertion failure in isession_handle_evt().

Impact

An assertion failure causes tmm to create a core file and restart. Traffic disrupted while tmm restarts.

Conditions

This issue can occur when a virtual server's iSession profile is modified while idle iSession connections are awaiting reuse. The iSession profile must have connection reuse enabled for this problem to occur.

Workaround

Disable reuse-connection in iSession profile.

Fix Information

Unexpected iSession tunnel state transitions are handled without causing TMM to restart or create a core file.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips