DEPMOD(8) DEPMOD(8)
NAME
depmod - program to generate modules.dep and map files.
SYNOPSIS
depmod [ -b basedir ] [ -e ] [ -F System.map ] [ -n ] [ -v ] [ version ] [ -A ]
depmod [ -e ] [ -FSystem.map ] [ -n ] [ -v ] [ 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 com-
plex.
depmod creates a list of module dependencies by reading each module under /lib/modules/version and determining what symbols it exports and
what symbols it needs. By default, 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, mod-
ules.symbols.bin.
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).
depmod will also generate various legacy map files in the output directory for use by the older hotplug infrastructure. These map files are
largely deprecated.
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
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.
-C --config file or directory
This option overrides the default configuration file at /etc/depmod.conf (or the /etc/depmod.d/ directory if that is not found).
-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 ker-
nel. 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 espencially when additionally updated third party drivers are not correctly installed or were
built incorrectly.
-F --filesyms System.map
Supplied with the System.map produced when the kernel was built, this allows the -e option to report unresolved symbols.
-h --help
Print the help message and exit.
-n --dry-run
This sends the resulting modules.dep and the various map files to standard output rather than writing them into the module direc-
tory.
-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.
COPYRIGHT
This manual page originally Copyright 2002, Rusty Russell, IBM Corporation. Maintained by Jon Masters and others.
SEE ALSO
depmod.conf(5), depmod.d(5), modprobe(8), modules.dep(5)
2010-03-01 DEPMOD(8)
