We've had this before: when we remove infrastructure to generate files, the old stale build artifacts still remain in-tree. And when the infrastructure to generate them is gone, so is the gitignore file for those build artifacts. End result: git will see the old generated files, and people will mistakenly commit them. That's what happened with the 'genheaders' file not that long ago (see commit 04a3389b3535 "Remove stale generated 'genheaders' file"). This time it's commit 9c54baab4401 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it") that removed the 'build' file from the arch/x86/boot/tools/ subdirectory, and removed the .gitignore file too (because the whole subdirectory is gone). And as a result, if you don't do a 'git clean -dqfx' or similar to clean up your tree, 'git status' will say Untracked files: (use "git add <file>..." to include in what will be committed) arch/x86/boot/tools/ and some hapless sleep-deprived developer will inevitably decide that that means that they need to 'git add' that directory. Which would bring back some stale generated file that we most definitely do not want in the tree. So when removing directories that had special .gitignore patterns, make sure to add a new gitignore entry in the parent directory for the no longer existing subdirectory. It will avoid mistakes. Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Fixes: 9c54baab4401 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>