Does /proc/config.gz always contain all supported options of a kernel?

somanyquestions · 07-30-2021, 07:59 AM

Assuming I have a running Linux system that has the /proc/config.gz file:

Does the (unpacked) file always contain all of the options the particular kernel supports, including commented out like:

Code:

#CONFIG_SOMETHING is not set

or is it possible that some options which the kernel supports do not appear at all in that file?

(the usefulness of knowing that for sure is to, perhaps, be able to do some problem hunting without currently having access to the buildroot config files that were used to create the Linux image at hand)

syg00 · 07-30-2021, 08:27 AM

If /proc/config.gz exists it will be the config used to build the current kernel. All config options available to that kernel build will either be selected or not.
Dependant options may (will ?) not exist if the primary option is not selected. Very few things in life are "black and white".

somanyquestions · 07-30-2021, 08:55 AM

Quote:

Originally Posted by syg00

If /proc/config.gz exists it will be the config used to build the current kernel. All config options available to that kernel build will either be selected or not.
Dependant options may (will ?) not exist if the primary option is not selected. Very few things in life are "black and white".

Ahh... dependent options, that makes sense!