How do some real time vendors license Linux when it is already open source?

I have had a hard time finding licensing models for companies/distributions like Wind River Linux and RedHawk Linux.

  • 3
    Can you elaborate what you mean by "get away with licensing Linux"? This would help get better answers. Jan 24, 2017 at 10:38
  • Is it not GPL? Do they provide full source for their stuff? Are drivers written for their distribution GPL'd also?
    – user_ABCD
    Jan 24, 2017 at 11:14
  • 1
    It's your question, so you tell us. You claim that some real time vendors are licensing Linux in a manner that you think is questionable. Philippe has asked you to clarify, so please do: which vendors are doing questionable things, and what are those questionable things?
    – MadHatter
    Jan 24, 2017 at 11:31
  • I didn't think my question was too confusing. I simply mentioned 2 vendors you can find by a simple google. I thought all things Linux were GPL, so I was confused on what licensing model exists for such vendors.
    – user_ABCD
    Jan 24, 2017 at 15:06
  • 1
    I upvoted you because i grok your question somehwo and I think it make some sense.... But your question is not precise and explicit enough. It feels vague and could stated more clearly rather than in comments. For instance: Linux is GPL-licensed. Some vendors such as XX and YY sell commercial products for RT based on and including Linux. How is this possible under the GPL? How can they comply with the terms of the GPL and in particular source code redistribution? Must the drivers and LKMs they provide be licensed under the GPL? Jan 26, 2017 at 10:46

1 Answer 1


Typically vendors such as RedHat, WindRiver, SUSE Enterprise, etc. license support for Linux. The packages they provide will be licensed under open source license such as MIT, GPLv2, BSD, etc. just like a typical Linux distribution. For licenses that require source distribution, e.g. GPLv2, these vendors certainly will comply and give you the full source.

What is entailed in the "support" that vendors supply? Security updates, newer versions of the packages, and debugging the software they provide. They sometimes might even help you debug applications you write on top of the software they support or debug their software running on your custom hardware. If you've ever tried to debug a kernel oops or a user-space application that you didn't write, you know it's not always the easiest to find the problem in somebody else's code. This is where the Linux vendors excel.

They're not just selling you the free software, they make the individual software components work together, debug your setup, and provide updates for both security and new features.

Edit: Note that Linux can become preemptive with the preempt-rt patch set and a kernel configuration option, so I geared my answer towards general commercial Linux. It is worth noting that not all commercial Linux vendors may support the preempt-rt flavor of Linux.

  • Not sure why I am getting down votes. @airfishey if I write a driver for say RHEL, is it GPL? Do I need to provide source?
    – user_ABCD
    Jan 25, 2017 at 11:24
  • 1
    @user_ABCD It's possible some of the users that down voted did not understand how your question relates to open source. Since this is the Open Source Stack Exchange, please explicitly state how your question relates to open source. An example: "How can real time vendors license Linux when it's already open source?".
    – airfishey
    Jan 25, 2017 at 15:44
  • @user_ABCD It seems this is a new question that deviates from your original commercial Linux vendor question. In the future, I suggest a new post dedicated solely to your question when changing topics. I will answer your new question in my next comment.
    – airfishey
    Jan 25, 2017 at 15:50
  • 1
    @user_ABCD In regards to your GPL driver question, it depends on how you write the "driver". When I think of a Linux driver, I often think of a kernel module. I would strongly suggest licensing Linux kernel modules as GPLv2 unless you have a good lawyer and a good understanding of what you need to do to allow you to license a kernel module as proprietary/closed-source. However, there are some proprietary kernel modules out there (Nvidia). However, it is possible to write a GPLv2 kernel module and a proprietary user space application that interfaces with the module via normal system calls.
    – airfishey
    Jan 25, 2017 at 15:56
  • See elinux.org/…
    – airfishey
    Jan 25, 2017 at 15:57

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