When creating an lnet self test session without the lnet_selftest module loaded I see the following message:
This is misleading as the real problem is not the parameter list, but the fact that lnet_selftest is not loaded. To an uninformed user, this can be extremely confusing.
From a quick scan of the code, the error occurs here:
Because the module is not loaded, the ioctl fails and sets errno to EINVAL. lst_print_error then interprets this error code and prints the misleading message. It would be much better if something was reported to the user which hinted at a possible unloaded module.
Something like the following would be much better:
Better yet, if the ioctl fails, the lst command could parse /proc/modules to determine if lnet_selftest is loaded.