How is the Linux kernel tested?
embeddedbits.org
How is the Linux kernel tested?
1–10 of 59 posts
Re: How is the Linux kernel tested?
#2So what happens when Linus Torvalds dies? Is there someone else who will become BDFL?
Re: How is the Linux kernel tested?
#3So what happens when Linus Torvalds dies? Is there someone else who will become BDFL?
Greg Kroah-Hartman has filled in before when Linus has had to take time off.
Re: How is the Linux kernel tested?
#4Long way of saying "it's not".
Re: How is the Linux kernel tested?
#5Long way of saying "it's not".
Fuck you.
I hate comments like this on HN.
The article clearly elaborates which methods/tools are used in their test process.
Re: How is the Linux kernel tested?
#6Long way of saying "it's not".
Re: How is the Linux kernel tested?
#7Re: How is the Linux kernel tested?
#8Why is there such little emphasis on “traditional” testing, that is, regular unit tests? At least some portion of the code base is surely suitable for normal unit tests. For example data structures, scheduling algorithms, file systems, ...
Re: How is the Linux kernel tested?
#9Why is there such little emphasis on “traditional” testing, that is, regular unit tests? At least some portion of the code base is surely suitable for normal unit tests. For example data structures, scheduling algorithms, file systems, ...
I think the main reason is that the Linux kernel (and similarly the *BSD kernels) are written in a programming language (C) that doesn't make it easy to do that. Code is often directly built on top of other kernel subsystems without any dependency injection whatsoever. This means that it's still possible to do unit testing of parts of the kernel, but it takes a crazy amount of effort, such as overriding symbols, overriding include paths and provide stub headers, etc..
I am well aware that it's also possible to have dependency injection in C by using structs with function pointers, but I think we can all agree that it's a lot less pleasant to use than C++ abstract base classes, Go interfaces or Rust traits. This is why the Linux kernel only tends to use this sparingly (e.g., inode operations).
Re: How is the Linux kernel tested?
#10Why is there such little emphasis on “traditional” testing, that is, regular unit tests? At least some portion of the code base is surely suitable for normal unit tests. For example data structures, scheduling algorithms, file systems, ...
You could test data structures (which tend to be implemented using macros), but any nontrivial subsystem of a monolithic kernel lives in a web of dependencies with other subsystems. This is especially true of Linux.
To solve this, you would need to either use a hierarchical decomposition of subsystems or do some crazy mocking to run subsystems outside of the full kernel.
There is a recent project (KUnit) to add a unit testing framework to the Linux kernel, but it remains to be seen how much adoption it will get.