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 un-
der <BASEDIR>/<MODULEDIR>/version. By default <MODULEDIR> is /lib/mod-
ules 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 mod-
ules.dep.bin, in the same directory. If filenames are given on the com-
mand line, only those modules are examined (which is rarely useful un-
less all modules are listed). depmod also creates a list of symbols pro-
vided 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-tmp-
files).
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 mod-
ules.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/mod-
ules/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/mod-
ules/$(uname -r) and generates index files under that same direc-
tory.
-m moduledir, --moduledir=moduledir
Override the module directory <MODULEDIR>, which defaults to
/lib/modules prefix set at build time. This is useful when building
modules.dep file in basedir for a system that uses a different pre-
fix, e.g. /usr/lib/modules vs /lib/modules.
Relative and absolute paths are accepted, but they are always rela-
tive to the basedir.
Examples:
depmod -b /tmp/build -m /kernel-modules
depmod -b /tmp/build -m kernel-modules
This expects all input files under /tmp/build/kernel-modules/$(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/$(uname -r) and gener-
ates index files under the same directory. Unless libkmod is pre-
pared to handle that arbitrary location, it won't work in runtime.
-o outdir, --outdir=outdir
Set the output directory where depmod will store any generated file.
outdir serves as a root to that location, similar to how basedir is
used. Also this setting takes precedence and if used together with
basedir it will result in the input being that directory, but the
output being the one set by outdir.
If a relative path is given, it's relative to the current working
directory.
Example:
depmod -o /my/build/staging/dir/
This expects all input files under /lib/modules/$(uname -r) and gen-
erates 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 dep-
mod.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 pro-
vided 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 pro-
vided 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 Corpora-
tion. Portions Copyright Jon Masters, and others.
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
<linux-modules@vger.kernel.org> 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 specific parts of the project.
Lucas De Marchi <lucas.de.marchi@gmail.com> is the current maintainer of
the project.
kmod 2025-04-25 DEPMOD(8)
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