Depmod

A program to generate modules.dep and map files.

DESCRIPTION Linux kernel  modules  can provide services (called "symbols") for other modules to use (using EXPORT_SYMBOL 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 modules.dep 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).

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 map files in this directory, for use by the hotplug infrastructure.

From the depmod man page