64 votes

How to sign a kernel module Ubuntu 18.04

In order to get VirtualBox working without simply disabling UEFI Secure Boot, then you'll need to do the following: Create a personal public/private RSA key pair to sign the kernel modules. As ...
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  • 741
48 votes
Accepted

Directory - /sys in linux

From sysfs.txt: sysfs is a ram-based filesystem [...]. It provides a means to export kernel data structures, their attributes, and the linkages between them to userspace. In essence /sys allows ...
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46 votes

Enable user namespaces in Debian kernel

On Debian the ability to create or handle user namespaces from a non-privileged process (usually meaning non-root user) is disabled by default. There's a Debian-specific patch (from Ubuntu) to the ...
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  • 4,263
30 votes

VirtualBox Ubuntu Guest Additions not installing : modprobe vboxsf failed

Ok, so this is a known problem. Instead of using the image provided by virtualbox you should just download it trough aptitute sudo apt-get install virtualbox-guest-dkms and if you need the headers ...
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  • 1,206
29 votes

Unable to install VIrtualbox, `"Specify KERN_DIR=<directory>"` -- installing Virtual Box to Debian?

How to fix this for Fedora/CentOS First make sure that your installed packages (especially kernel) are up to date: $ sudo yum update If it updates the kernel version, you will have to restart ...
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  • 409
21 votes

How to sign a kernel module Ubuntu 18.04

I know that this question is old, but because there is no accepted answer and none of these answers solved the issue for me, I am writing how I solved this today: When running this command, get this ...
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15 votes
Accepted

IPsec in the Linux Kernel

The IPsec stack integrated in the Linux kernel since 2.6 (NETKEY) was originally based on the KAME stack (at least in regards to the API). The source code is part of the kernel repository, where the ...
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  • 1,158
12 votes

Directory - /sys in linux

Can't beat Wikipedia's simplicity: Filesystem Hierarchy Standard > FHS compliance Modern Linux distributions include a /sys directory as a virtual filesystem (sysfs, comparable to /proc, which ...
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  • 1,829
12 votes
Accepted

How to view all boot messages in Linux after booting?

So your console has two types of messages: generated by the kernel (via printk); generated by userspace (usually your init system). Kernel messages are always stored in the kmsg buffer, visible via ...
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  • 376k
11 votes

Is it possible to make the OOM killer intervent earlier?

For me setting vm.admin_reserve_kbytes=262144 does exactly this thing. OOM killer intervents before system goes completely unresponsive.
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11 votes

Is it safe to enable user namespaces in CentOS 7.4 and how to do it?

Namespaces is a kernel feature used by containers like LXC or docker. You have several kinds, PID namespaces, user namespaces,... And you're right, it's quite complicated at first. I find this old ...
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  • 3,057
10 votes

VirtualBox Ubuntu Guest Additions not installing : modprobe vboxsf failed

open the terminal and run sudo reboot. then try to install again via devices -> Insert Guest Additions CD Image. worked for me.
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  • 249
10 votes

What is "modloop" option in Alpine?

The modloop= option specifies a SquashFS filesystem that gets mounted to /.modloop by the init file /etc/init.d/modloop and symlinked from /lib/modules (or possibly union-mounted with the overlay - ...
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9 votes

What is the exact difference between the parameters (pgpgin, pswpin) and (pswpout, pgpgout) in /proc/vmstat?

So old question and no correct answer so far. First of all, memory is segmented by CPU and Kernel into so called pages. Size of page is given by architecture of CPU, many architectures support ...
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  • 2,033
9 votes

How to install kernel rc rawhide in Fedora?

You could enable the whole rawhide repository, and then just install the kernel. But, for the kernel in specific, we have a better way. The Rawhide kernel is built with debugging turned on, which can ...
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  • 2,647
8 votes
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Uninstall latest kernel using yum

How can I remove this latest kernel from my system? I was apparently specifying the version incorrectly. This works: $ sudo yum remove kernel-3.10.0-229.1.2.el7 How can I prevent it from being ...
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8 votes

Which is the user‑space command for resuming from hibernation?

The short answer is /sys/power/resume Much longer answer, because that by itself won't do much if any good. Most distros recommend initiating a resume from the init / PID 1 process (early user space)....
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  • 4,270
7 votes

What does "sudo -s" actually do?

sudo -s runs the shell specified in your $SHELL environment variable as the superuser/root. You can specify another user using -u. The $SHELL environment variable contains the path to the user's ...
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  • 171
6 votes

How to get a list of active drivers that are statically built into the linux kernel?

The sysfs module area /sys/module is a view into all the modules visible to the running kernel. Each module directory has a set of sysfs interface files to view and manage the module via userspace. ...
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  • 161
6 votes

How do I stop rfkill module from hardblocking my wifi, without rfkill command?

I had the same problem on my Raspberry.  A simple sudo apt-get install rfkill did the job.  I was then able to unblock my devices with rfkill unblock all
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6 votes
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Where are Kernel Headers for Fedora 21?

To compile programs that build Linux kernel modules, such as VMware Tools, VMware Workstation, etc., you should install both the relevant kernel-headers and kernel-devel packages. The kernel-headers ...
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6 votes
Accepted

Why is USB Serial so fast in linux?

There is no actual serial link to run at 115,200 baud or any other baud rate. The interface a serial link would provide is emulated to allow the modem to work with software designed to work with an ...
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6 votes

How do I fix Manjaro error hibernation device not found on boot?

I keep having this problem in Arch Linux and Manjaro, when my Laptop runs out of battery while being in standby. My solution in Arch is to run: sudo mkinitcpio -p linux Under Manjaro you might ...
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6 votes

How do I fix Manjaro error hibernation device not found on boot?

Did you repartition your swap? If so, the UUID of the swap partition, which is used for hibernation, may have changed. Then this procedure may help. Live-boot and access your filesystem by mounting ...
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  • 161
6 votes

How to sign a kernel module Ubuntu 18.04

I had this issue. Disable Secure Boot : https://wiki.ubuntu.com/UEFI/SecureBoot/DKMS
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  • 161
6 votes

How to sign a kernel module Ubuntu 18.04

I had the same issue on Ubuntu 20.04, but could not understand why. I tried all the above options but they did not quite work for me. Signing packages seems a bit complex and unnecessary, so I am not ...
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  • 61
5 votes
Accepted

dkms does not find kernel source

After a looong debug session I found that the build and source links in /lib/modules/2.6.32-openvz-042stab090.5-amd64 to /usr/src and /usr/include were missing. Added them manually and it worked. ...
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  • 565
5 votes

How to check which SysRq functions are enabled?

Here is a Bash one-liner which will print you the enabled options: for i in $(seq 1 8); do (( ($(</proc/sys/kernel/sysrq) & $((1<<$i))) > 0 )) && echo $((1<<$i)); done ...
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  • 22.6k
5 votes

wait for kernel after creating partition with sftdisk on linux

Later, but better than never. For completeness. udevadm settle --timeout=15 --exit-if-exists=$PARTITION
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5 votes

Is there any Linux command that I can use to show all the network interfaces except ifconfig

The ifconfig tool (from net-tools) is being deprecated in favour of the ip tool, which is part of the iproute2 suite. This will list interfaces, and their ip addresses if they have one: ip addr
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