Everything about UNIX kernels: development, configuration, compilation, design, etc.

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auditctl reports “File system watches not supported” on a very old system

When I run auditctl -l I got: # auditctl -l No rules File system watches not supported And I've already have AUDITSYSCALL enable in kernel, # zgrep AUDIT /proc/config.gz CONFIG_AUDIT_ARCH=y ...
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What kernel for ARM architechture, Linux or BSD? [closed]

I'm a computer sciences student and recently started a project with the engineering department that involves an onboard ARM processor, the question is what sort of operating system, kernel and ...
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1k views

How can I check my kernel preemption configuration?

I want to check if my Linux kernel is preemptive or non-preemptive. How can I check this using a command, something such as uname -a?
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Can the kernel be moved to a different mtd while the system is running?

I am attempting to do a full update on a mobile Linux Arm device. I have successfully pivoted my file system root and have been able to flash a new file system to that mtd. What I would like to ...
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Ubuntu 12.04.1 LTS - /boot is using 98.4% of 193MB

I have a problem. I have noticed that my VPS is saying : => /boot is using 98.4% of 193MB Looks like something went wrong, doesn't it? I have tried to run dpkg -l | grep linux to check what's ...
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disable transparent hugepages

We are installing SAP HANA in a RAID machine. As part of the installation step, it is mentioned that, To disable the usage of transparent hugepages set the kernel settings at runtime with echo ...
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What is the language that appears on the first line of a script? [duplicate]

Bash scripts start with the following line #!/bin/bash # Rest of script below ... In bash the # character is the start of a comment, but #!/bin/bash is definitely not a comment, therefore it isn't ...
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How to add more /dev/loop* devices on Fedora 19

How to add more /dev/loop* devices on Fedora 19? I do: # uname -r 3.11.2-201.fc19.x86_64 # lsmod |grep loop # ls /dev/loop* /dev/loop0 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 /dev/loop5 ...
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Can I list the filesystems a running kernel can support?

I'm trying to detect what filesystems a kernel can support. Ideally in a little list of their names but I'll take anything you've got. Note that I don't mean the current filesystems in use, just ones ...
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Building example device driver error: insmod invalid module format

I am following the tutorial @ http://www.embeddedsystemonline.com/home/embedded-system/embedded_linux/lab3-linux-device-driver on step #7 of this tutorial, $ cd ...
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884 views

“kernel driver” in “lspci” output

I often use lspci -v to check the LKM in use for particular hardware device. LKMs are listed as "Kernel modules" and can be seen with lsmod. However, what is a "Kernel driver"? For example here: Is ...
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How much RAM does the kernel use?

This question is motivated by my shock when I discovered that Mac OS X kernel uses 750MB of RAM. I have been using Linux for 20 years, and I always "knew" that the kernel RAM usage is dwarfed by X ...
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Why linux is a monolithic kernel, while you can load/unload modules (e.g. drivers)? [duplicate]

Hybrid- and Microkernels are flexible, in the way one can add any higher-level functionality as a module, is it not the same for linux kernels? Why then linux is called a monolithic?
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Upgrading Red Hat 9 (Shrike) kernel manually

I am following the instructions here on how to manually perform a kernel upgrade in Red Hat. The current Kernel RPM's are: kernel-2.4.20-8 kernel-headers is not installed kernel-ibcs is not ...
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How do you get hardware info and select drivers to be kept in a kernel compiled from source?

I would like to create a minimal kernel for a web server. When you compile a kernel from source how do you get hardware info and then know what drivers need to be kept in the kernel so the rest can ...
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Detecting kernel thread on pre-3.0 kernels

Looking at the proc man page (http://man7.org/linux/man-pages/man5/proc.5.html) it is possible to detect which processes are kernel threads in /proc/<pid>/stat by looking at the flags value ...
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dmesg email digest

I have a remote server which has some issues (Seem hardware related) which means that it logs KVM errors and then sometime later it becomes unresponsive and locked up. There is an often an early ...
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Need small distro without a desktop or windows manager, just to run a single graphical app [duplicate]

I am looking for some help on this from a linux expert. I am very novice when it comes to linux so I am hoping someone can help out. I need a small distro, that is stable. I don't need a full X ...
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Making a bootable pendrive for custom kernel

I read the tutorials to make a mimalistic custom kernel from here and am able to boot it up as explained in the tutorial over a virtual machine using GRUB as the boot loader. I think it would be more ...
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387 views

Processes in Linux

As I understand it, process descriptors are stored in a doubly linked list data structure. But a fork can create multiple children for the same process, so that makes me think that there is a tree ...
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793 views

ttyS1/uart1 initialised but not accessible through /dev/ttyS1

I'm not sure at which level I am having a problem. System is a LeopardBoard DM368 running TI's own SDK / LSP / BusyBox kernel, the core Linux kernel is 2.6.x so using serial_core.c driver model. By ...
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User space to kernel space transition

Both physically (hardware, rings) and logically (software), what is user space to kernel space transition? And vice versa. Or more generally what goes on when there is a "space" (or ring) transition ...
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963 views

LinuxMint15: Suspend to RAM not working

I just installed LinuxMint15 on an Acer Aspire V3-771G-73638G500Maii. Hibernation works. But suspend to RAM does not. When clicking suspend: After a few seconds the screen goes grey and then off. ...
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Rings and run levels

The question stated below might not be technically correct(misconception) so it would be appreciable if misconception is also addressed. Which ring level do the different *nix run levels operate in? ...
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How do I verify that the Linux kernel is not freezing when uploading or downloading large data over the ethernet interface?

How to verify if the Linux kernel is doing what it's saying for network interfaces? I have one network interface eth0 which has hardware support to do 1GB full-duplex. I have prepared 2 box. Now ...
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281 views

Why do people call Linux a kernel rather than an OS?

Why do people refer to Linux as a kernel rather than an operating system? To the best of my knowledge, the kernel is one part of the operating system.
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Kernel pppd task hung after running over serial port

I am trying to run the ppp daemon on the console port of my board which has p2020 processor with Linux kernel 2.6.32. After running ppp interface ppp0 is not coming up and I get an error pppd blocked ...
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error: “net.inet.ip.fastforwarding” is an unknown key

I've been doing some research into improving performance for OpenVPN and I found out about setting fastforwarding to 1 but when I tried I got the error error: "net.inet.ip.fastforwarding" is an ...
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75 views

Why have a fake LR-WPAN driver?

In the Linux kernel configuration, a fake LR-WPAN driver can be enabled and added to the kernel that will be compiled. Why would someone want a fake LR-WPAN driver? I assume it would be for debugging, ...
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Are the outputs of /proc/meminfo, /proc/cpuinfo etc always in English?

I am writing code that relies on the output of /proc/meminfo, /proc/cpuinfo etc. Are the file contents always in English? For example, will MemTotal in /proc/meminfo always be MemTotal in all locales? ...
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731 views

How can I install Arch Linux on a Laptop with Intel GMA 4500 MHD?

I would like to install Arch Linux on my Acer TravelMate 5735Z. Sadly, it has a Intel GMA 4500 MHD graphic card. This means, I suffer from Kernel Bug [GM45] black screen at boot (0 backlight?). When ...
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Is there any difference between these two configuration options?

Is there any actual difference between iptables -P FORWARD DROP and net.ipv4.ip_forward = 0 ? I know that one is a firewall command while the other one is a kernel option. But: I don't know ...
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Kernel panic after building kernel in Red Hat Linux?

I've been trying to build a new kernel for Red Hat Enterprise Linux virtual installs under VM Ware. I've followed these steps so far: Download the kernel from kernel.org. Extract the downloaded ...
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why would there be a load of 5 if there are zero processes in the runq?

This doesn't make sense to me, why would there be a load of 5 if there are zero processes in the runq? 12:00:01 AM runq-sz plist-sz ldavg-1 ldavg-5 ldavg-15 12:05:01 AM 0 708 ...
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How to specify an ISO as the location of root filesystem for GRUB?

I'm trying to understand the Debian "booting from Hard Disk" installation manual. The process is as follows: I copy a kernel image, a ramdisk initrd and an ISO with installer to the hard drive and ...
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How can I compile, install and run the tools inside kernel/tools?

There are some tools in side the kernel, <kernel source root directory>/tools perf is one of them. In ubuntu I think the tools inside this folder is available as package linux-tools How ...
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710 views

What happened to `vga=ask` in newer kernels?

I used to activate framebuffer mode in the "older" kernels with vga=ask, and later setting it to a value, once I've figured out which one works best for me. Now, this option seems to be gone, the ...
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Could the Kernel stack of a process be empty, when a process is swapped out to a disk?

I am just curious to know whether the Kernel stack could be empty when a process is swapped out to a disk or not?
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Can Linux “run out of RAM”?

I saw several posts around the web of people apparently complaining about a hosted VPS unexpectedly killing processes because they used too much RAM. How is this possible? I thought all modern OS' ...
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How can I install perf 3.4.25?

By installing perf using sudo apt-get install linux-tools-common sudo apt-get install linux-tools-3.2.0.23 gave me perf version 3.2.14 How can I install perf 3.4.25? Is it related to kernel ...
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ACPI Errors/Exeptions, why they spam, how to know and fix it?

I've been having these errors pollute my dmesg: [21720.400079] ACPI Error: [\_TZ_.THRM] Namespace lookup failure, AE_NOT_FOUND (20130328/psargs-359) [21720.400093] ACPI Error: Method parse/execution ...
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Linux Mint Debian quits on boot

I just upgraded Linux Mint Debian Edition with the up7 package. The update manager failed initially (can't remember where...) so I ran sudo apt update, sudo apt dist-upgrade, sudo apt upgrade and ...
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Linux process “scheduling”

I've seen it written many times that the Linux scheduler schedules processes. I'm teaching a course on multithreaded programming, and would like to get my terminology straight. I have one thing I ...
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452 views

TUN/TAP Will not load

I have an OpenVZ server but can't seem to get the tun/tap module to load. I ran modprode tun on the hostnode but when I go under the VM I get: Tue Sep 24 03:08:36 2013 Note: Cannot open TUN/TAP dev ...
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Confusion with Linux kernel [closed]

I am really confused with the kernel concepts. I came to know that the kernel is between application and hardware, and that the kernel takes input from the applications and it will send the ...
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What's the difference between a kernel oops and a kernel panic?

I know what a kernel panic is, but I've also seen the term "kernel oops". I'd always thought they were the same, but maybe not. So: What is a kernel oops, and how is it different from a kernel panic? ...
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How to fix unreliable Realtek Wireless card on Ubuntu 13.04

I have a Realtek RTL8188CE wireless card and it works fine when I have a strong signal, but if I get even slightly away from the wifi I lose connectivity even though there is a strong Rx signal. I ...
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283 views

What changed between kernels 3.2 and 3.9 that affect MiniDLNA?

I'm using Debian testing, and I've problems with MiniDLNA on kernel > 3.2. The DLNA client works about 30 min, after that it lost the connection with the minidlna server and can't discover the server ...
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1k views

Features that Linux kernel has and Windows does not? [closed]

What are the significant technical features the Linux kernel has that the Windows does not? Something that I might find on a kernel feature list, which is conceptually an advantage, or significantly ...
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Is there kernel patch to prevent load files into RAM for LiveCD?

Is there kernel patch to prevent load files into RAM for LiveCD? I mean, if I'm use LiveCD with "boot to Ram" option, there is no needs for kernel to load executable binaries to RAM from RAM. It ...