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

Last Modified: Sep 13, 2023

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

Known Affected Versions:
11.5.1, 11.5.2

Fixed In:

Opened: Dec 01, 2014

Severity: 2-Critical

Related Article: K16206


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

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips