How exactly is RedHat not showing a commitment to open source? Do they invest in open source? CHECK. Do they contribute to the adoption of open source? CHECK. Are they abiding by the open source licenses that govern the use of the open source on which they rely? CHECK.
All they have done in this case is make a legal, wise, and likely necessary move to protect themselves. Nothing they have done damages the kernel or prevents you from getting it. Nothing they have done damages any other OS projects.
Sounds like you've got a whole mouthful of sour grapes there...
They're withholding documentation for "open source" code they wrote. You're welcome to argue that's okay, sound business, etc. but if they were committed to open source they would release documentation alongside their code.
Red Hat is under that obligation to give out their source code. They are under no obligation to explain it to you. For that, you have to pay them, or figure it out yourself. I have no problem with that model. Why should you feel entitled to their knowledge base or documentation if you haven't paid for it?
What it comes down to is that paywalled documentation is, in my experience, universally inferior to documentation that is publicly available. In my last job I saw "Proprietary Information of <company>" stamped over all the documentation I used, and the thing was the most insulting thing I'd ever seen. The "information" was less useful than the reverse engineering my colleagues had done over the years.
Red Hat's documentation is better now, but documentation tends to rot when people can't see it until they're in the midst of using it. I feel entitled to the knowledge base because I'm not paying for something unless I have a good idea of the sort of issues I'll have when using it, and what the company does to resolve them. Red Hat has made a fine business respecting this up until now.
On the other hand, a lack of publicly available documentation is less important when source is available.
IIRC the GPL does, actually, require you to enumerate your changes to the code. This doesn't necessarily have to be in the form of a diff, though, and can be in a ChangeLog instead.
2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
a) You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change.
b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
c) If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.)
Seems like all it requires is that you say "We changed this file, and we changed it on this date." I suppose one could question whether giving detailed information about the changes is simply the "spirit of the rule" or if it's actually "going above and beyond."
It sounds like the problem you both have is a high sense of entitlement for something that the license doesn't entitle you to have...why is Red Hat at fault for asking you to pay for something that wasn't at all free or easy to create?
Where did I say they were at fault? All I said was that they're making a significant move away from their open source business model.
Now in your post that I was replying to, on the other hand, you clearly seem to be talking about the broader social contract that the open source community is organized around. Red Hat makes the best code and documentation they have available to anyone, and in return the community does the same.
Red Hat has loudly trumpeted the superiority of this social contract over the proprietary avenue. Now their documentation has become proprietary. That says to me they believe the social contract and the business model they've built around it are somehow flawed.
Personally, I don't have a dog in this fight, and so I don't feel at all entitled to their documentation. If I'm working with Red Hat I'll be working with someone who has a support contract. But if I were, for example, someone involved with Fedora who had worked on resolving issues in Red Hat, I would feel like Red Hat was acting improperly, regardless of legality. Are you arguing that it's okay to free ride on the work of the community and not give back what you create? Stop muddying the waters by flitting back and forth between morality and legality, please.
Devil's advocate: software isn't free or easy to create either. Maybe open source license should require "best-effort" documentation, or prevent the witholding of it.
They are withholding the intermediate steps between their kernel and a vanilla one. They are not withholding the source code - you can study it, change it and even diff it against the vanilla kernel to see what they changed.
I bet some comments may even help you figure out why they made a specific change.
Unfortunately, I believe all Oracle will just pay some proxy for RH support and get the same individual patches.
It's sound business because I'd rather RedHat continue to be the leader in the space of commercial open source than Oracle. We've seen what Oracle does to open source since they acquired Sun and it's not pretty.
If, hypothetically, they were able to close, to own, the source they were dealing with, it really wouldn't matter how much they'd invested in the previously open source. It would be just source they invested in 'cause they wanted to sell it and there would be nothing "altruistic" about it (and no benefit for any who didn't pay them).
So, no, they can't compensate for withholding information by investing in open source. They might currently be only withholding an "acceptable" amount but their investment in open source and their information-withholding can't be naively compared to see if they "balance out".
All they have done in this case is make a legal, wise, and likely necessary move to protect themselves. Nothing they have done damages the kernel or prevents you from getting it. Nothing they have done damages any other OS projects.
Sounds like you've got a whole mouthful of sour grapes there...