Bug ID 700405: Disabling TCP segmentation offload can lead to a tmm assert

Last Modified: Jun 10, 2021

Bug Tracker

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

Known Affected Versions:
13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 13.1.3.5, 13.1.3.6, 13.1.4, 13.1.4.1

Fixed In:
14.0.0

Opened: Jan 02, 2018
Severity: 3-Major

Symptoms

If using vmxnet3 or virtio tmm drivers (not unic), if TCP segmentation offload is disabled while processing traffic, a tmm assert may be observed and tmm will restart. The tmm assert appears similar to the following: notice tso ioctl for member:0 of /Common/internal failed with value: 32tso ioctl for member:0 of /Common/external failed with value: 32panic: ./local/net/packet.h:328: Assertion "packet_ref: not free" failed.

Impact

Sometimes tmm will restart, which will lead to traffic group failovers. This is a fairly rare situation, and disabling TCP segmentation offloading is not something routinely done, but if done while under load, this failure might occur.

Conditions

-- Deploy Virtual Edition (VE) using vmxnet3 or virtio tmm drivers. -- Continuously pass traffic through the system. -- Disable the DB variable tm.tcpsegmentationoffload.

Workaround

There is no workaround at this time.

Fix Information

This issue no longer occurs.

Behavior Change