depmod [-b basedir] [-e] [-E Module.symvers] [-F System.map] [-m]
[-n] [-v] [-A] [-P prefix] [-w] [version]
depmod [-e] [-E Module.symvers] [-F System.map] [-m] [-n] [-v]
[-P prefix] [-w [ [version] [filename ...] ] ]
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 /lib/modules/version and determining what symbols it exports and
what symbols it needs. By default, this list is written to mod-
ules.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 mod-
ules.devname if modules supply special device names (devname) that
should be populated in /dev on boot (by a utility such as udev).
If a version is provided, then that kernel version's module directory
is used rather than the current kernel version (as returned by uname
depmod will also generate various legacy map files in the output direc-
tory for use by the older hotplug infrastructure. These map files are
-a --all Probe all modules. This option is enabled by default if no
file names are given in the command-line.
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
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
espencially when additionally updated third party drivers are
not correctly installed or were built incorrectly.
When combined with the -e option, this reports any symbol
versions supplied by modules that do not match with the sym-
bol versions provided by the kernel in its Module.symvers.
This option is mutually incompatible with -F.
-F --filesyms System.map
Supplied with the System.map produced when the kernel was
built, this allows the -e option to report unresolved sym-
bols. This option is mutually incompatible with -E.
-h --help Print the help message and exit.
-m This overrides any possible configuration file setting of
make_map_files and forces the generation of legacy map files,
such as modules.pcimap.
This sends the resulting modules.dep and the various map
files to standard output rather than writing them into the
-P Some architectures prefix symbols with an extraneous charac-
ter. This specifies a prefix character (for example '_') to
In verbose mode, depmod will print (to stdout) all the sym-
bols each module depends on and the module's file name which
provides that symbol.
Show version of program and exit. See below for caveats when
run on older kernels.
-w Warn on duplicate dependencies, aliases, symbol versions,
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