Engineers working on the kernel and drivers have a dilemma. They cannot test the code for every conceivable platform because they do not have that many resource

Engineers working on the kernel and drivers have a dilemma. They cannot test the code for every conceivable platform because they do not have that many resources. They will test the code for the devices they have, and then ask for others to test on other similar platforms. This is because the code is near metal. The most the developers can do is to develop using the design-by-contract methodology. But that too goes out of the window when others start supporting more platforms and devices. So the only approach that has worked is solid code reviews. There was a very interesting email exchange between Linus and an engineer from Sun. Linus was rejecting his patch because there was a spelling mistake in a comment. That's how strict he is about code quality.