class_set_global() incorrectly accepts parameters whose name is empty, such as "=value". For an input beginning with =, the calculated off is 0.

size_t off = value - param - 1;

The subsequent comparison:

strncmp(lustre_attrs[i]->name, param, off)

becomes strncmp(..., ..., 0), which always returns 0. As a result, the first attribute in lustre_attrs[] is incorrectly selected and its store callback is invoked with the supplied value. An empty parameter name should not match any attribute.

Expected behavior

• Reject parameters with an empty name, e.g. "=value".
• Return an appropriate error such as -EINVAL.
• Only match an attribute when a non-empty parameter name is provided and it matches the attribute name.