Driver bug in Linux 5.10? After upgrade from 4.19 lots of illegal loopback warnings in dmesg

I just upgraded a host with a MT27710 Family [ConnectX-4 Lx] adapter from Linux 4.19 to 5.10, and now dmesg is filling up with:

bond1: (slave enp179s0f0np0): An illegal loopback occurred on slave

Check the configuration to verify that all adapters are connected to 802.3ad compliant switch ports

These messages do not occur on Linux 4.19, switch seems correctly configured and connection appears to work. So is this just a driver bug in the 5.10 kernel?

Hello Eli,

Thank you for posting your inquiry on the NVIDIA Networking Community.

Based on the information provided, the issue looks related to a firmware issue of the adapter. On the RedHat site, there is KB article related to this →

We recommend to upgrade the f/w of the adapter to the latest available. You can download the latest f/w through the following link →

Thank you and regards,

~NVIDIA Networking Technical Support

I can confirm after upgrading to

firmware-version: 14.31.1014 (MT_2420110004)


firmware-version: 14.26.1040 (MT_2420110004)

the issue appears to have resolved, thanks.