Cfrtjryk

Is there a way to know if the kernel was compiled with a certain option activated (i.e. CONFIG_PROC_EVENTS=y) without having to pull out the kernel sources package and looking in the config file?

If you look through your /boot directory you'll notice these files:

$ ls -l /boot/|grep config

-rw-r--r--  1 root root   109919 Oct 21  2011 config-2.6.35.14-100.fc14.x86_64

-rw-r--r--  1 root root   109919 Oct 27  2011 config-2.6.35.14-103.fc14.x86_64

-rw-r--r--  1 root root   109919 Nov 23  2011 config-2.6.35.14-106.fc14.x86_64

Notice what version of the Kernel you're using:

$ uname -r

2.6.35.14-106.fc14.x86_64

If you grep through the appropriate "config-uname -r" file you can see what options the Kernel was built with:

$ grep CONFIG_PROC_EVENTS= /boot/config-`uname -r`

CONFIG_PROC_EVENTS=y

References

• How To Check What Kernel Build Options Enabled In The Linux Kernel?

Kernel options can be found in /proc/config.gz.

zgrep CONFIG_PROC_EVENTS= /proc/config.gz

if the kernel was compiled with CONFIG_IKCONFIG_PROC=y.

If your kernel was build with CONFIG_IKCONFIG_PROC, you can find the configuration listed in /proc/config.gz

zless /proc/config.gz

Debian and Redhat based kernel packages generally install a config-$version file in /boot,

less /boot/config-$(uname -r)

In Debian you can also find the default options in kernel-package's ./kernel/Config/config as well as architecture specific configuration options in ./kernel/Config/.

mkdir /tmp/k

cd /tmp/k

apt-get source kernel-package

find . -path '*/kernel/Config/*' -type f

sudo find / -xdev -name .config(-xdev keeps it on one filesystem)

Generally it will be under /usr/src/some-specific-kernel-header-version/.config

Just read it as any text, search with grep, or to see how two versions differ diff -y -suppress-common-lines /path/linux2.6-r3/.config /path/linux2.6-r4/.config