Linux kernel : Kernel version string appended with either ''+" or "-dirty"

Question

I am trying to install latest kernel from git of Linus Torvalds, i.e., version 3.16-rc7. I have created a new branch by following using following commands: git checkout -b v_3_16 v3.16-rc7 Then I checkout on the branch v_3_16 and fire following commands make menuconfig and check the option CONFIG_LOCALVERSION_AUTO because I need the version string to be updated. But I cannot understand why does this append "+" or "-dirty" (when CONFIG_LOCALVERSION_AUTO is disabled) to the version string. I have checked out for uncommited changes using git commit -a but it says nothing to commit.

Answer 1

If Linux kernel images are being built with "-dirty" on the end of the version string, this simply means that modifications in the source directory have not been committed. Use git status to check for uncommitted files.

When you see the dirty string, it appends the kernel version string with the last abbreviated commit id + dirty to the kernel version.

You can use the above Git command to report modified, removed, or added files. You should commit those changes to the tree regardless of whether they will be saved, exported, or used. Once you commit the changes, you need to rebuild the kernel.

To force a pickup and commit of all such pending changes, enter the following:

 $ git add .
 $ git commit -s -a -m "getting rid of -dirty"

Alternatively, use the make -j2 LOCALVERSION="-customstring" to get the custom string

Answer 2

"Create an empty .scmversion file in the root of the kernel sources."