Symptoms

tmm might drop packets and eventually result in tmm crash.

Impact

Rare reboot with message: tmm process might crash with assertion 'we always have room in tx ring!'.

Conditions

This intermittent issue might occur when TSO is enabled (enabled by default) because of TSO handling combined with certain stressful transmit conditions, as a result of which the system attempts actions on memory or content that has already been freed.

Workaround

None. If TSO is not disabled, three related fixes are needed to fully address the issue: -- ID 466260, covered in SOL15953: TMM may produce a core file with the 'Assertion we always have room in tx ring! failed' error message. -- ID 502238, covered in SOL16736: The BIG-IP system may lose connectivity and fail to process all traffic through TMM if the HSB is overloaded. -- ID 509782, covered in SOL16780: The BIG-IP system may drop TSO packets. The Solutions are available here: -- https://support.f5.com/kb/en-us/solutions/public/15000/900/sol15953.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16736.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16780.html

Fix Information

This release fixes a crash bug where TMM asserts 'we always have room in tx ring'. Three related fixes are needed to fully address the issue: -- ID 466260, covered in SOL15953: TMM may produce a core file with the 'Assertion we always have room in tx ring! failed' error message. -- ID 502238, covered in SOL16736: The BIG-IP system may lose connectivity and fail to process all traffic through TMM if the HSB is overloaded. -- ID 509782, covered in SOL16780: The BIG-IP system may drop TSO packets. The Solutions are available here: -- https://support.f5.com/kb/en-us/solutions/public/15000/900/sol15953.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16736.html -- https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16780.html

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips