Bug ID 876677: When running the debug version of TMM, an assertion may be triggered due to an expired DNS lookup.

Last Modified: May 29, 2024

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

Known Affected Versions:
15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1

Fixed In:
17.0.0, 16.1.2.2, 15.1.6.1

Opened: Feb 04, 2020

Severity: 2-Critical

Symptoms

When running the debug version of TMM, if a particular DNS lookup takes more than 30 seconds, TMM may assert with a message in the /var/log/tmm file similar to the following example: notice panic: ../modules/hudfilter/3dns/cache_resolver.c:2343: Assertion "standalone refcnt must be one" failed.

Impact

TMM crashes and, in redundant configurations, the unit fails over.

Conditions

-- Using the debug TMM -- Using the RESOLV::lookup iRule command -- The DNS server targeted by the aforementioned command is running slowly or malfunctioning

Workaround

Do not use the debug TMM.

Fix Information

The debug assert was removed and replaced by a debug log.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips