Bug ID 547657: A TCL error in a DNS_RESPONSE iRule event can cause a tmm crash.

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP GTM, LTM(all modules)

Known Affected Versions:
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 HF1, 11.5.3 HF1, 11.5.3 HF2, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4

Fixed In:
11.6.1 HF1

Opened: Sep 22, 2015

Severity: 3-Major

Symptoms

A TCL error, such as referencing an undefined variable, in a DNS_RESPONSE iRule event can cause a tmm crash. This can occur on a UDP listener with a DNS profile without datagram load balancing enabled. A DNS_REQUEST event, with any content, on the same listener is also required.

Impact

Traffic disrupted while tmm restarts.

Conditions

All of the following: UDP listener with DNS profile without datagram load balancing. A TCL error, such as referencing an undefined variable, in a DNS_RESPONSE iRule event. A DNS_REQUEST iRule event with any content.

Workaround

Either add datagram load balancing to the listener or correct the TCL errors that lead to the problem.

Fix Information

The TCL error handling is now processed asynchronously which prevents the problem from occurring.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips