Going by the numbers from https://lwn.net/Articles/895800/ https://lwn.net/Articles/895800/ Intel is the top documented contributor to the overall kernel (as o

Going by the numbers from https://lwn.net/Articles/895800/ https://lwn.net/Articles/895800/ Intel is the top documented contributor to the overall kernel (as opposed to the "core" of the kernel, which is defined here has non-driver, non-architecture dependent code) with 11.4%, whereas Oracle has 2.2%. 7.7% are attributed to "unknown", 5.5% as "none", and 2.4% as "consultant". Almost 2/3 of that combined quantity would need to be attributed to Oracle in order to make up the gap, which seems unlikely. So the definition of "core" seems to be the key factor here. Intel, AMD, IBM, Huawei, Linaro and Red Hat contribute substantial amounts of architecture-dependent code and/or driver code which isn't counted in this metric.