Manual: depmod

DEPMOD(8)						   depmod						   DEPMOD(8)

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 //version.	 By  default
         is	/lib/modules  and   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	mod‐
       ules.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  where modules are located. If your modules are not currently in the (nor‐
	   mal) 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 , which defaults to /lib/modules prefix set at build time. This is use‐
	   ful 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. Un‐
	   less 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 re‐
	   sult 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/$(uname -r)	and  generates	index  files  under  /my/build/stag‐
	   ing/dir/lib/modules/$(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.

COPYRIGHT
       This manual page originally Copyright 2002, Rusty Russell, IBM Corporation. Portions Copyright Jon Masters, and	oth‐
       ers.

SEE ALSO
       depmod.d(5), modprobe(8), modules.dep(5)

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.

AUTHORS
       Numerous contributions have come from the linux-modules mailing list  and	 Github.  If
       you have a clone of kmod.git itself, the output of git-shortlog(1) and git-blame(1) can show you the authors for spe‐
       cific parts of the project.

       Lucas De Marchi  is the current maintainer of the project.

kmod							 2026-02-02						   DEPMOD(8)