Bug ID 514521: Rare TMM Cores with TCP SACK and Early Retransmit

Last Modified: Jun 30, 2021

Bug Tracker

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

Known Affected Versions:
10.2.4, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4

Fixed In:
12.0.0, 11.6.0 HF5

Opened: Mar 26, 2015
Severity: 2-Critical
Related AskF5 Article:
K16417

Symptoms

In certain isolated cases, TCP profiles with Early Retransmit and SACK enabled will cause a TMM Crash.

Impact

Traffic disrupted while tmm restarts.

Conditions

The connection is not in fast recovery but a SACK hole has been retransmitted.

Workaround

Disable Early Retransmit in the TCP profile.

Fix Information

Early retransmit now handles corner cases where the SACK scoreboard is empty.

Behavior Change