# depmod

## NAME



           depmod - Generate modules.dep and map files.
    


## SYNOPSIS



           **depmod**[**-b** _basedir_] [**-m** _moduledir_] [**-o** _outdir_] [**-e**]
           [**-E** _Module.symvers_]
                  [**-F** _System.map_] [**-n**] [**-v**] [**-A**] [**-P** _prefix_] [**-w**] [_version_]
    
           **depmod**[**-e**] [**-E** _Module.symvers_] [**-F** _System.map_] [**-n**] [**-v**] [**-P**
           _prefix_]
                  [**-w**] [_version_] [_filename_...]
    


## DESCRIPTION



           Linux kernel modules can provide services (called "symbols") for
           other modules to use (using one of the EXPORT_SYMBOL variants in
           the code). If a second module uses this symbol, that second module
           clearly depends on the first module. These dependencies can get
           quite complex.
    
           **depmod** creates a list of module dependencies by reading each
           module under <BASEDIR>/<MODULEDIR>/_version_. By default <MODULEDIR>
           is /lib/modules and <BASEDIR> is empty. See options below to
           override when needed. It determines what symbols each module
           exports and needs.  This list is written to **modules.dep** , and a
           binary hashed version named modules.dep.bin, in the same
           directory. If filenames are given on the command line, only those
           modules are examined (which is rarely useful unless all modules
           are listed). **depmod** also creates a list of symbols provided by
           modules in the file named modules.symbols and its binary hashed
           version, modules.symbols.bin. Finally, **depmod** will output a file
           named modules.devname if modules supply special device names
           (devname) that should be populated in /dev on boot (by a utility
           such as systemd-tmpfiles).
    
           If a _version_ is provided, then that kernel version's module
           directory is used rather than the current kernel version (as
           returned by **uname -r**).
    


## OPTIONS



           **-a** , **--all**
               Probe all modules. This option is enabled by default if no
               file names are given in the command-line.
    
           **-A** , **--quick**
               This option scans to see if any modules are newer than the
               **modules.dep** file before any work is done: if not, it silently
               exits rather than regenerating the files.
    
           **-b** _basedir_ , **--basedir** _basedir_
               Override the base directory <BASEDIR> where modules are
               located. If your modules are not currently in the (normal)
               directory /lib/modules/_version_ , but in a staging area, you can
               specify a _basedir_ which is prepended to the directory name.
               This _basedir_ is stripped from the resulting **modules.dep** file,
               so it is ready to be moved into the normal location. Use this
               option if you are a distribution vendor who needs to pre-
               generate the meta-data files rather than running **depmod** again
               later.
    
               If a relative path is given, it's relative to the current
               working directory.
    
               Example:
                   depmod -b /my/build/staging/dir/
    
               This expects all input files under
               _/my/build/staging/dir/lib/modules/$(uname -r)_ and generates
               index files under that same directory.
    
           **-m** _moduledir_ , **--moduledir** _moduledir_
               Override the module directory <MODULEDIR>, which defaults to
               /lib/modules prefix set at build time. This is useful when
               building **modules.dep** file in _basedir_ for a system that uses a
               different prefix, e.g. _/usr/lib/modules_ vs _/lib/modules_.
    
               Relative and absolute paths are accepted, but they are always
               relative to the _basedir_.
    
               Examples:
                   depmod -b /tmp/build -m /kernel-modules
                   depmod -b /tmp/build -m kernel-modules
    
               This expects all input files under _/tmp/build/kernel-_
               _modules/$(uname -r)_ and generates index files under that same
               directory.
    
               Without an accompanying **-b** argument, the moduledir is relative
               to _/_. Example:
    
                   depmod -m foo/bar
    
               This expects all input files under _/foo/bar/$(uname -r)_ and
               generates index files under the same directory. Unless libkmod
               is prepared to handle that arbitrary location, it won't work
               in runtime.
    
           **-o** _outdir_ , **--outdir** _outdir_
               Set the output directory where **depmod** will store any generated
               file. _outdir_ serves as a root to that location, similar to how
               _basedir_ is used. Also this setting takes precedence and if
               used together with _basedir_ it will result in the input being
               that directory, but the output being the one set by _outdir_.
    
               If a relative path is given, it's relative to the current
               working directory.
    
               Example:
                   depmod -o /my/build/staging/dir/
    
               This expects all input files under _/lib/modules/$(uname -r)_
               and generates index files under
               _/my/build/staging/dir/lib/modules/$(uname -r)_.
    
           **-C** _file or directory_ , **--config** _file or directory_
               This option overrides the default configuration files. See
               depmod.d(5).
    
           **-e** , **--errsyms**
               When combined with the **-F** option, this reports any symbols
               which a module needs which are not supplied by other modules
               or the kernel. Normally, any symbols not provided by modules
               are assumed to be provided by the kernel (which should be true
               in a perfect world), but this assumption can break especially
               when additionally updated third party drivers are not
               correctly installed or were built incorrectly.
    
           **-E** _Module.symvers_ , **--symvers** _Module.symvers_
               When combined with the **-e** option, this reports any symbol
               versions supplied by modules that do not match with the symbol
               versions provided by the kernel in its _Module.symvers_. This
               option is mutually incompatible with **-F**.
    
           **-F** _System.map_ , **--filesyms** _System.map_
               Supplied with the _System.map_ produced when the kernel was
               built, this allows the **-e** option to report unresolved symbols.
               This option is mutually incompatible with **-E**.
    
           **-h** , **--help**
               Print the help message and exit.
    
           **-n** , **--show** , **--dry-run**
               This sends the resulting **modules.dep** and the various map files
               to standard output rather than writing them into the module
               directory.
    
           **-P**
               Some architectures prefix symbols with an extraneous
               character. This specifies a prefix character (for example '_')
               to ignore.
    
           **-v** , **--verbose**
               In verbose mode, **depmod** will print (to stdout) all the symbols
               each module depends on and the module's file name which
               provides that symbol.
    
           **-V** , **--version**
               Show version of program and exit. See below for caveats when
               run on older kernels.
    
           **-w**
               Warn on duplicate dependencies, aliases, symbol versions, etc.
    


## BUGS



           Please direct any bug reports to kmod's issue tracker at
           https://github.com/kmod-project/kmod/issues/ alongside with
           version used, steps to reproduce the problem and the expected
           outcome.
    


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