118
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I accidentally deleted my .config for my kernel configuration on Linux, and seem to remember there was a way to retrieve the kernel configuration via the proc filesystem somehow.
Is this still possible, and if so how would I do it?
Sonny Ordell
Posted 2011-05-23T10:49:38.847
Reputation: 1 357
118
Depending on your system, you'll find it in any one of these:
/proc/config.gz/boot/config/boot/config-$(uname -r)and possibly more places.
new123456
Posted 2011-05-23T10:49:38.847
Reputation: 3 707
in /boot/config-$(uname -r) for amazon linux and likely RHEL – aeb0 – 2016-11-27T23:47:25.957
1Not existing such files on Ubuntu Mate or Kali Linux for RaspBerry Pi. – Sopalajo de Arrierez – 2017-10-05T23:23:05.530
1You should mention that your first item (/proc) is only available if module "configs" is loaded – Andy – 2018-02-27T07:41:21.313
4On some distros (Fedora/Redhat) it's /boot/config-2.6.18-194.el5 or similar, with the kernel release string appended. – Phil – 2011-05-23T15:50:03.057
1@Phil I run a distro (Zenwalk) where those filenames are symlinked by the latest kernel package to /boot/config. I'll go ahead and add these to the list - thanks for reminding me. – new123456 – 2011-05-23T20:15:32.463
57
For an actual running kernel, one way to get the config file this is to
cat /proc/config.gz | gunzip > running.config
or,
zcat /proc/config.gz > running.config
Then running.config will contain the configuration of the running linux kernel.
However this is only possible if your running linux kernel was configured to have /proc/config.gz. The configuration for this is found in
General setup
[*] Kernel .config support
[*] Enable access to .config through /proc/config.gzMost distributions do not have this configuration set. They provide kernel config files in their kernel packages and is usually found in /boot/ directory.
Jarl
Posted 2011-05-23T10:49:38.847
Reputation: 671
5These are known as CONFIG_IKCONFIG and CONFIG_IKCONFIG_PROC, if you're grepping for them. – chronospoon – 2015-03-26T18:34:28.727
2zcat /proc/config.gz works fine. – Quanlong – 2016-08-22T04:15:49.470
39
A Little bit late but maybe it helps someone. I didn't have /proc/config.gz nor /boot/config nor /boot/config-$(uname -r) on my Computer. I had to run modprobe configs as root. Then, /proc/config.gz was present
Thomas Sparber
Posted 2011-05-23T10:49:38.847
Reputation: 491
Can confirm on Intel MIC embedded Linux (BusyBox), this is necessary and works. – Mark Lakata – 2016-02-23T18:59:59.963
4Same for Raspbian on Raspberry Pi 2 – Drew McGowen – 2016-03-24T02:39:30.057
2FATAL: Module configs not found. on OMV 2.2 (Debian Wheezy) so glad they provided it in /boot/config-$(uname -r) – tuk0z – 2016-04-12T11:42:10.040
You sir, saved my day. Have a +1 – Christian – 2018-01-14T10:26:15.467
'modprobe configs' is very helpful I had tests that automatically probe kconfig that were failing on a Raspberry Pi 3, but now work. Thanks for the tip!! – Tim Bird – 2019-01-03T00:40:54.783
9
If you couldn't find kernel configuration in /boot/ nor in /proc/config.gz, you can try extracting this information from the kernel itself.
Inside any kernel source code there is a script for extracting config located in scripts/extract-ikconfig, pass the kernel you want its configuration as parameter to this script.
This solution will only work if Kernel .config support was enabled in the compiled kernel.
Ramast
Posted 2011-05-23T10:49:38.847
Reputation: 191
2This was extremely helpful and helped me to obtain plenty of configs I didn't expect to ever see. Thanks! – selurvedu – 2017-10-02T14:16:58.620
6
Independently of the distribution, you can run: cat /lib/modules/$(uname -r)/build/.config
Source: https://linux.die.net/man/5/proc (search for /proc/config).
jgomo3
Posted 2011-05-23T10:49:38.847
Reputation: 281
1
For RedHat-based distributions, the .config file of the off-the-shelf kernel can be found with the command cat /lib/modules/$(uname -r)/build/.config that's available after the package kernel-devel is installed using the command:
yum -y install kernel-devel
Note that with the real Red Hat Enterprise Linux distribution, you will need to enable the source-repository to get this package. On RHEL8, use the following command to do that:
subscription-manager repos --enable=rhel-8-for-x86_64-baseos-source-rpms
Gertjan Bijl
Posted 2011-05-23T10:49:38.847
Reputation: 11
2http://superuser.com/questions/577307/how-to-get-a-list-of-active-drivers-that-are-statically-built-into-the-linux-ker || http://askubuntu.com/questions/163304/which-device-drivers-are-built-into-the-kernel || http://stackoverflow.com/questions/14376540/view-linux-kernel-config-options || http://unix.stackexchange.com/questions/83319/how-can-i-know-if-the-current-kernel-was-compiled-with-a-certain-option-enabled || http://serverfault.com/questions/51032/how-do-i-check-what-kernel-options-were-compiled-without-looking-at-boot-config – Ciro Santilli 新疆改造中心法轮功六四事件 – 2016-08-07T15:44:16.320
@Sonny Ordell: There are now two valid answers. Can you accept one of them? – Hennes – 2013-10-02T14:43:28.133
3@Hennes User has not been online since
Jun 27 '11 at 16:19. Don't think he's going to be accepting anything. – DanteTheEgregore – 2013-10-02T14:49:20.297