CODEWITHSUNDEEP
linuxkernel-module
Jacob Marble
Jacob Marble

Reputation: 30242

How to find the version of a compiled kernel module?

I am in a situation where it would be very convenient to find the version of a loaded kernel module by querying the loaded module or .ko file.

Is there a standard way to do this without digging into the source code?

Upvotes: 13

Views: 14273

Answers (2)

Ciro Santilli OurBigBook.com
Ciro Santilli OurBigBook.com

Reputation: 384454

Runtime method

insmod /module_version.ko

cat /sys/modules/module_version/version
# => 1.0

cat /sys/module/module_version/srcversion
# => AB0F06618BC3A36B687CDC5

modinfo /module_version.ko | grep -E '^(src|)version'
# => version:        1.0
# => srcversion:     AB0F06618BC3A36B687CDC5

Tested with this setup on kernel 4.9.6.

/sys/modules/module_version/version

version is set by the MODULE_VERSION macro.

The file does not exist if the MODULE_VERSION macro is not used in the module.

/sys/module/module_version/srcversion

srcversion is an MD4 hash of the source code used to compile the kernel module. It is calculated automatically at build time from https://github.com/torvalds/linux/blob/v4.9/scripts/mod/modpost.c#L1978 using https://github.com/torvalds/linux/blob/v4.9/scripts/mod/sumversion.c#L400

To enable it, either:

The srcversion file is only present when if one of the above holds.

You can then check that the built .ko matches the insmodded one with:

modinfo mymod.ko

This is a very useful sanity check when you are developing your own kernel modules and copying modules between machines.

From inside module code itself with THIS_MODULE

You can use THIS_MODULE->version, here is an example: What is the significance of THIS_MODULE in Linux kernel module drivers?

Upvotes: 4

Sdaz MacSkibbons
Sdaz MacSkibbons

Reputation: 28716

$ apropos modinfo
modinfo              (8)  - display information about a kernel module
$ modinfo cpuid.ko
filename:       cpuid.ko
author:         H. Peter Anvin <[email protected]>
description:    x86 generic CPUID driver
license:        GPL
vermagic:       2.6.37 SMP preempt mod_unload PENTIUM4 gcc-4.4.5
depends:

Upvotes: 10

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