Bug ID 933809: Too many interrupts from console serial port starve TMM for CPU time

Last Modified: May 29, 2024

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

Known Affected Versions:
14.1.2,,,,,,,,, 14.1.3,, 14.1.4,,,,,,, 14.1.5,,,,,, 15.1.0,,,,,, 15.1.1, 15.1.2,, 15.1.3,, 15.1.4,, 15.1.5,, 15.1.6,, 15.1.7, 15.1.8,,, 15.1.9,, 15.1.10,,,, 16.1.0, 16.1.1, 16.1.2,,, 16.1.3,,,,,, 16.1.4,,,, 17.0.0,,

Opened: Aug 05, 2020

Severity: 4-Minor


Kernel log file will show this message: "err kernel: serial8250: too much work for irq4" In some conditions when there are too many of these, TMM may crash.


Traffic disrupted while tmm restarts.


Occurs due to performing heavy I/O over the serial console. For example, running tcpdump and dumping the output to the console while the device is under heavy load.


Avoid using the console for issuing commands that produces a lot of output.

Fix Information


Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips