Bug ID 625198: TMM might crash when TCP DSACK is enabled

Last Modified: Sep 13, 2023

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

Known Affected Versions:
11.2.1, 11.4.0, 11.4.1, 11.5.0, 11.5.1, 11.5.2, 11.5.3, 11.5.4, 11.5.5, 11.5.6, 11.6.0, 11.6.1, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2

Fixed In:
13.0.0, 12.1.2 HF1, 11.6.2, 11.5.7

Opened: Oct 27, 2016

Severity: 2-Critical


TMM crashes


Traffic disrupted while tmm restarts.


All of the below are required to see this behavior: DSACK is enabled MPTCP, rate-pace, tail-loss-probe, and fast-open are disabled. cmetrics-cache-timeout is set to zero; congestion control is high-speed, new-reno, reno, or scalable; AND Nagle is not set to 'auto'. an iRule exists that changes any of the conditions above besides DSACK. various client packet combinations interact in certain ways with the iRule logic.


Change any of the conditions above.

Fix Information

TCP maintains state appropriately to avoid crash.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips