The vmkernel.log file on an VMware vSphere ESXi host contains one of these or similar entries
cpu2:10234)WARNING: CBT: 986: Unsupported ioctl 58
cpu2:10234)WARNING: CBT: 986: Unsupported ioctl 43
cpu2:10234)WARNING: CBT: 986: Unsupported ioctl 59
cpu2:10234)WARNING: CBT: 986: Unsupported ioctl 60
These warning messages are harmless and can be safely ignored