> Any provision in an employment agreement which provides that an employee shall assign, or offer to assign, any of his or her rights in an invention to his or her employer shall not apply to an invention that the employee developed entirely on his or her own time without using the employer’s equipment, supplies, facilities, or trade secret information except for those inventions that either:
> (1) Relate at the time of conception or reduction to practice of the invention to the employer’s business, or actual or demonstrably anticipated research or development of the employer or ...
I am not a lawyer, but I think it would not be unreasonable to believe that work on the kernel would be related to IBM's business (like RedHat).
Its not just that it doesn't compete with the employer's business but if it is related to the employer's business.
Furthermore, while the own time/equipment is there, there is also trade secret information mentioned beyond the time and equipment constraint.