Bug ID 493558: TMM core due to SACK hole value mismatch

Last Modified: Nov 07, 2022

Bug Tracker

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

Known Affected Versions:
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, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1

Fixed In:

Opened: Dec 01, 2014
Severity: 2-Critical
Related Article:


TMM cores with 'sack scoreboard population counts valid' assert. The TMM core occurs due to lost-packet retransmitted packet value mismatch.


Traffic disrupted while tmm restarts.


This occurs when processing retransmitted packets configured for selective acknowledgement (SACK), when multipath TCP (MPTCP) and selective negative acknowledgement (SNACK) are enabled with a SNACK-supporting client.


There are two possible workarounds: -- Disable MPTCP. -- Disable the SNACK option in the TCP profile.

Fix Information

TMM handles the case, and no longer cores due to lost-packet retransmitted packet value mismatch.

Behavior Change