Don't add "+" to linux kernel version

Question

I am building linux kernel, if my kernel under git, then kernel version every time is:

Image Name:   Linux-2.6.39+

If I am not using git, then everything is OK without any plus at the end.

I know that this done by scripts/setlocalversion script:

if test "$CONFIG_LOCALVERSION_AUTO" = "y"; then
    # full scm version string
    res="$res$(scm_version)"
else
    # append a plus sign if the repository is not in a clean
    # annotated or signed tagged state (as git describe only
    # looks at signed or annotated tags - git tag -a/-s) and
    # LOCALVERSION= is not specified
    if test "${LOCALVERSION+set}" != "set"; then
        scm=$(scm_version --short)
            res="$res${scm:++}"
        fi
fi

So, it is possible without code changes say to build system that no need to add "+" at the end of version line?

Solution 1

The plus sign at the end of your version string is there as an indicator that the kernel was built from modified sources (that is, there were non-committed changes). This is also indicated by the comments in scripts/setlocalversion.

To avoid the '+' being appended despite having a dirty working directory, simply set LOCALVERSION explicityly when running make:

make LOCALVERSION=

You may also have to change the configuration option CONFIG_LOCALVERSION_AUTO to n in your kernel config (.config) before building:

sed -i "s|CONFIG_LOCALVERSION_AUTO=.*|CONFIG_LOCALVERSION_AUTO=n|" .config

Solution 2

To prevent the script scripts/setlocalversion to append the + to the end of the kernel local version, create an empty .scmversion file in the root of the kernel sources.

touch .scmversion

this way, you'll be able to leave LOCALVERSION as is in the kernel configuration file, in case you want to append a local signature to the kernel name.

Comments

[Gauthier]

I do get a + at the end of my vmlinuz and initrd.img, yet git status says "nothing to commit, working directory clean". It is my own commit though, does the + appear because I am not on the official master branch? Or maybe since I built locally the working directory is not clean although the dirt is gitignored?

[Jon Gjengset]

I'm not entirely sure.. You should have a look at scripts/setlocalversion and see exactly what it is testing for when setting +.

[Gauthier]

Apparently, it also adds a plus if your working directory is clean, but your current git HEAD has no tag.

[Gauthier]

Ah, but that's not all of it. I have my own branch, tagged commit, clean working dir, but I still get the +.

[Peterlits Zo]

@Gauthier Same as you >_<