Bug ID 466260: TMM may produce a core file with the 'Assertion we always have room in tx ring! failed' error message

Last Modified: Feb 13, 2019

Bug Tracker

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

Known Affected Versions:
11.4.1, 11.5.0, 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

Fixed In:
11.6.0, 11.5.1 HF5

Opened: Jun 09, 2014
Severity: 2-Critical
Related AskF5 Article:
K15953

Symptoms

tmm might drop packets and eventually result in tmm crash.

Impact

tmm process might crash with assertion 'we always have room in tx ring!".

Conditions

This intermittent issue might occur when TSO is enabled (enabled by default) because of TSO handling combined with certain stressful transmit conditions, as a result of which the system attempts actions on memory or content that has already been freed.

Workaround

Disable TSO and restart services: tmsh sys db tm.tcpsegmentationoffload value disable. If TSO is not disabled, three related fixes are needed to fully address the issue: -- ID 466260, covered in SOL15953: TMM may produce a core file with the 'Assertion we always have room in tx ring! failed' error message. -- ID 502238, covered in SOL16736: The BIG-IP system may lose connectivity and fail to process all traffic through TMM if the HSB is overloaded. -- ID 509782, covered in SOL16780: The BIG-IP system may drop TSO packets. The Solutions are available here: -- https://support.f5.com/kb/en-us/solutions/public/15000/900/sol15953.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16736.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16780.html

Fix Information

This release fixes a crash bug where TMM asserts 'we always have room in tx ring'. Three related fixes are needed to fully address the issue: -- ID 466260, covered in SOL15953: TMM may produce a core file with the 'Assertion we always have room in tx ring! failed' error message. -- ID 502238, covered in SOL16736: The BIG-IP system may lose connectivity and fail to process all traffic through TMM if the HSB is overloaded. -- ID 509782, covered in SOL16780: The BIG-IP system may drop TSO packets. The Solutions are available here: -- https://support.f5.com/kb/en-us/solutions/public/15000/900/sol15953.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16736.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16780.html

Behavior Change