In the past, it was common practice for people to symlink the /usr/include/linux and asm directories to /usr/src/linux/include/linux and asm respectively. This is a bad idea as this extract from a post by Linus Torvalds to the Linux Kernel Mailing List points out: I would suggest that people who compile new kernels should: - not have a single symbolic link in sight (except the one that the kernel build itself sets up, namely the "linux/include/asm" symlink that is only used for the internal kernel compile itself) And yes, this is what I do. My /usr/src/linux still has the old 2.2.13 header files, even though I haven't run a 2.2.13 kernel in a _loong_ time. But those headers were what glibc was compiled against, so those headers are what matches the library object files. And this is actually what has been the suggested environment for at least the last five years. I don't know why the symlink business keeps on living on, like a bad zombie. Pretty much every distribution still has that broken symlink, and people still remember that the linux sources should go into "/usr/src/linux" even though that hasn't been true in a _loong_ time. The relevant part here is where he states that the headers should be the ones which glibc was compiled against. These are the headers which should remain accessible and so by copying them, we ensure that we follow these guidelines. Also note that as long as you don't have those symlinks, it is perfectly fine to have the kernel sources in /usr/src/linux.