One aspect of open source that appeals to many people is the idea that anyone can contribute. All it takes is a great idea, a little bit of work, and you can have fame, glory, and more conference t-shirts than you know what to do with. The reality is often not quite as simple for many reasons. A common complication is software licencing. There are plenty of other locations talking about open source software licencing and the complications there of so this one will be narrowly focused and have a simple request: When submitting patches for the Linux kernel, whether to official kernel mailings lists or to Fedora, please remember sign off your patches.

Luis Rodriguez has a great blog post on the history of the DCO. In over simplfied terms, the DCO is an assertion of ‘Yes, I am permitted to include this code in this open source project’. Many projects, including the Linux kernel, require this assertion before taking any patch. Adding it is simple enough: simply add Signed-off-by: Your Name <your@e-mail.address> to the bottom of your commit text. If you can make the assertions in http://developercertificate.org, you can add a Signed-off-by.

Is the Signed-off-by needed in all patches? Yes. Even cleanup patches? Yes. Even patches that just add a few device ids? Yes. Even patches that don’t do anything useful? If a patch isn’t useful it shouldn’t be getting merged, but yes. A pattern I’ve seen a few times is

  • Person has problem
  • Person googles for problem
  • Person finds someone else had the same problem, someone else had a fix for the issue
  • Person tests the fix – it works!
  • Person excitedly e-mails the fix to maintainers to get it included

Often the fix lacks a proper DCO so even if the patch is perfect in any other way, the maintainers cannot take the patch. This leaves everyone feeling frustrated. But just because a patch was submitted once without a proper DCO doesn’t mean it can’t be re-submitted later; if you can get in contact with someone (e.g. original author, co-maintainer) who can make the assertions of the DCO, the patch can be resubmitted. Until that happens though there isn’t much the maintainers of the project can do with the patch.

It’s vital to the success of open source projects that licences are followed. So please, if you want your patch included make sure to add your Signed-off-by.