Assuming it's still the case, Red Hat used to release all their RHEL-kernel specific changes as individual patches, but apparently it made this too easy for Ora

Assuming it's still the case, Red Hat used to release all their RHEL-kernel specific changes as individual patches, but apparently it made this too easy for Oracle to copy and cherry-pick in the ones they wanted, so the Red Hat released source code became a big giant squished patch. They felt it still complied with GPLv2, and TBH, I don't think that it doesn't. Not necessarily in the spirit of the license, but a necessary solution against Oracle in their minds. GPLv3 defines it differently, but I doubt you could convince anyone of this in court. I think getting the source in any form would be a good enough start for most of the companies flaunting the GPL.