The kernel of operating systems popularly known as Linux, or sometimes GNU/Linux.

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What is a Kernel Routine ?

In another answer I met a short overview of the sections of the man pages: commands for $-User system call, that means evoking a function from the Kernel library call, that means evoking a function ...
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259 views

Does Linux virtual bridge support VLAN's?

Does Linux virtual bridge(configured with for example ip or brctl) support VLAN's? For example configure access ports in different VLAN's and trunk ports with only certain VLAN's enabled. Only option ...
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web cam starting hangs os

I faced a strange effect as ... when my notebook wakes up from suspend I can start and close my web cam with guvcview 1-3 times; But after while on 3dr or 4th starting attempt (I didn't count for ...
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How to understand virtual switch in Linux?

I have a following virtual Ethernet switch in Linux: root@vmhost:~# brctl show br0 bridge name bridge id STP enabled interfaces br0 8000.266b04c4a79a no ...
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Find out which kernel source files were used when kernel was compiled

I am compiling the Linux kernel for my specific hardware and I only select the drivers/options which I really need. This is in contrast to a typical distribution kernel, where they compile almost ...
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git: show which files have changed between kernel 3.18.6 and 3.18.7

I have checked out linux kernel git repository git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git I know how to use git log, git show and similar commands to see ...
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MMU-less kernel?

I would like to try compile mmu-less kernel. From what I found in configuration there is no option for such a thing. Is it possible to be done?
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Cross compile GLIBC : error: Need linker with .init_array/.fini_array support

Whenever I call glibc configure with --prefix=/usr --with-headers=/var/tmp/ubuild.wandboard-armhf.build_dir/armv7a-hardfloat-linux-gnueabi/sysroot/usr/include --host=armv7a-hardfloat-linux-gnueabi ...
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How to rotate the LCD screen/framebuffer to 180 degree?

I have a custom board with a Freecale i.MX6Q SoC. I am using Linux kernel 3.03.35 and LCD is 3.5 inch RGB type display. I want to rotate my LCD screen to 180 degree. I tried a lot to pass parameters ...
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Compiling a loadable kernel module outputs several warnings about undefined functions [closed]

This question is a follow up of this one. I am trying to compile the ELF loader as an individual LKM and use it as a standalone application(replacing the original module within the base kernel sounds ...
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How to insert a modified ELF loader given the current ELF loader is present?

I need to modify the ELF loader's kernel implementation of an Ubuntu 14.04 distribution. Having downloaded the sources using: sudo apt-get source linux-image-$(uname -r) I ran the configuration ...
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dracut md5sum boot directory

This has been going on for a few months now, but my initramfs (and kernel) for that matter have been placed in /boot/{some hash}/{kernel version}/{initramfs,linux}. Did dracut or some other module ...
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make: xscale_be-gcc: Command not found

I'm new to embedded and am reading 'Embedded Linux Primer' at the moment. I tried to build an xscale arm kernel: make ARCH=arm CROSS_COMPILE=xscale_be- ixp4xx_defconfig # # configuration written to ...
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1answer
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Re-enabling the console once the kernel is up, if silent mode was set in Uboot?

I have enabled the silent mode by setting the U-boot env variable "silent". Uboot-> setenv silent 1 Uboot-> saveenv Now, I would like to re-enable the console once the kernel is up. Can ...
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Gummiboot Kernel Parameters, Cannot find /boot/loader dir

I installed Gummi boot to my EUEFI partition which is sda1. when I do lsblk it show boot is mounted on sda2, which is also my root partition. when I ls '/boot' there is no loader dir. I need the ...
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Is it safe to upgrade kernel manually on a system which is using NVIDIA drivers?

Upgrading kernel manually on Ubuntu 14.04 can cause trouble with NVIDIA drivers? (one of the troubles could be booting to black screen) I had lot of trouble with installing NVIDIA graphics drivers ...
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Linux question: stat file modification for creator field [closed]

I modified stat structure in my new kernel, and I compiled and entered to new kernel version linux-3.19. The location of new kernel source code was present on desktop. While I try to print the stat ...
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Specifically what advantages does Kali Linux have other than preinstalled packages? [closed]

I have been using Kali Linux increasingly over the last few months. I also have an Ubuntu system, and have found that there are many similar tutorials on how to install Kali tools on Ubuntu. However, ...
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Trying to make a Universal Makefile

I'm working on my own netfilter module for the first time. According to internet documentation, The simplest module contains the following C code: //'Hello World' kernel module, logs call to ...
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Why do we need a usbkbd driver when there is usbhid?

I discovered that it is the usbhid that controls my USB keyboard by default. I discovered it by doing rmmod usbhid. When I removed usbhid the usb keyboard stopped working. Note that usbkbd was not yet ...
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1answer
61 views

What are the `some_name.o.cmd` files?

What are the some_name.o.cmd files that I see in Linux's kernel code? are they auto-generated?
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Centos 7 boot up with custom kernel problem

I have installed centos 7 on virtualbox machine which has kernel-3.10.0-123.20.1.el7.x86_64. I am trying to build Linux kernel from kernel sources. I downloaded the kernel source files from: ...
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RTC time synchronization not working (CONFIG_RTC_SYSTOHC)

I have the option CONFIG_RTC_SYSTOHC enabled in my kernel: Device Drivers ---> [*] Real Time Clock ---> [*] Set the RTC time based on NTP synchronization The help says: ...
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How/Where to learn about linux kernel? [closed]

I want to learn how the Linux kernel works, specifically about the following topics: structure, programming design, device development, but I do not know of good places to learn about these topics. I ...
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Linux Operating System and Version, Regardless of Distibution [duplicate]

I would like to know a linux command that can tell me the operating system and version regardless of what distribution I am using as it seems different distributions have a different way of doing ...
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Enabling ethernet over usb support in Linux Kernel

How to enable Ethernet over USB support in linux kernel. Which driver(like CONFIG_USB_USBNET) is related to this support. Is EEM (Ethernet Emulation) regarding this support or not..???
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modinfo when a module was compiled into kernel statically wouldn't work — workarounds?

modinfo is rather useful tool when it comes to tweaking module's parameters (at least discovering what options are availalbe), for e. g.: $ modinfo dummy filename: ...
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Constant 60KB Shared library memory on /proc/<pid>/maps

In a quest for understanding RAM requirements of system processes, I arrived to analysis of /proc/pid/maps. I have noticed a pattern: many shared libraries have exactly 60KB space allocated in their ...
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Kernel loglevel and console manipulation

I want to have two console kernel arguments, one /dev/tty2 for screen and one /dev/ttyAM0 for serial debugging. I can achieve that simply with: console=ttyAM0,115200 console=tty2 I want /dev/ttyAM0 ...
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Buildroot - missing i2c kernel modules

I've used Buildroot to build a minimal operative system. During the configuration step with the menuconfig utility I specified to install I2C tools. The option was is Target Package -> Hardware ...
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1answer
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How to list all loadable kernel modules?

I'm looking for a few kernel modules to load i2c-dev and i2c-bcm2708. But the modprobe command returns: sudo modprobe i2c-dev modprobe: module i2c-dev not found in modules.dep How can I list all ...
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update kernel without restart

Recently Linux got a new feature called Live Kernel Patching, which you means you dont have to restart your system to update kernel. Is there any other kernel which has this feature already or Linux ...
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What setsockopts() 'name' values are used by the running Linux kernel?

I am introducing some new socket commands with nf_register_sockopt(&my_new_socket_options). How can I find, what setsockopt commands are already used (registered?) by the currently running kernel, ...
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dmesg: pci BAR 7: can't assign io

I have VMware virtual machine running Debian Wheezy. I have compiled my own kernel 3.14. I have noticed dmesg is flooded with messages pci BAR 7: can't assign io (size 0x1000). I have no idea what ...
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1answer
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kernel: nf_conntrack: table full, dropping packet; Underlying Reason

I have a modified linux on an ARM9 processor. It was working OK, but yesterday I got this error repeatedly: kernel: nf_conntrack: table full, dropping packet I have 2 questions: How can I find ...
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doubts regarding memory control group and memory zones lru list?

I have doubts regarding memory control group and memory zones lru list ? I just want know whether memory control groups lru list is subset of memory zone lru list or they have different pages on them ...
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How is the linking mechanism so fast in the kernel system calls? [closed]

If I open any file in Linux kernel almost every file has many extern functions and many #indef or #ifndef macros so while compiling how exactly does it map all the functions and macros when more than ...
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How to instruct RHEL6.5 Linux to save/starts states before crush or restart

I have multiple Workspaces, each responsible for different revisions of the same software. Not to have to recreate all Worspaces and open all tools/windows, I'm wondering how can I instruct Linux to ...
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Detecting and categorizing device drivers in a running system

How can I obtain what device drivers are incorporated in a running kernel? More than this, how can I categorize these device drivers? For instance, this is a Linux kernel conceptual map, from ...
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Can a zImage be used with U-Boot and ArchLinuxARM?

I am using U-Boot on a Cubieboard 2, sun7i AllWinner A20 board to boot into ArchLinux ARM. The kernel version that I have is the sun7i latest, which is 3.4.103-5-ARCH so, in kernel terms, it's a bit ...
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“Last resort” Linux terminal command to reboot (over ssh) in case of a kernel bug?

I have a small server with Ubuntu 10.04 on it; I am manipulating this server from another computer via ssh, and I tried to use nfs on it to share files. That mostly works, until one of the clients ...
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module scsi_wait_scan not found on CentOS kernel-ml causes kernel panic on boot

I am attempting to upgrade from kernel-lt to kernel-ml, following the instructions here, however on boot the console is flooded with module "scsi_wait_scan" not found This leads to a general kernel ...
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What is “fs” short for in kernel function “get_fs()”?

There are two Linux kernel functions: get_ds() and get_fs() According to this article, I know ds is short for data segment. However, I cannot guess what "fs" is short for. Any explanations?
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Looking for a Distro for a beginner in kernel hacking

I'm currently trying to learn the basics of the linux kernel via Linux Kernel in a Nutshell and Linux Kernel Development books, the problem is that when using Ubuntu, there are a lot redundant ...
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Why is there AF_NETLINK? Is AF_UNIX not enough?

As far as I understand, AF_NETLINK socket protocol is for communicating between the kernel and userspace and AF_UNIX is for communication between two userspace processes. Why does Linux need a ...
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What does “task mysqld:xxx blocked for more than 120 seconds” mean?

We are troubleshooting a MySQL issue where some queries are taking a very long time complete and I see many of these entry in /var/log/messages: Jan 28 05:52:15 64455-alpha01 kernel: [2529273.616327] ...
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Looking for ancient kernel source

I'm looking for an specific old kernel source namely 2.6.26.5 to build an exact replicate of an cross toolchain for an embedded target. Unfortunately all I can find is 2.6.26 in the kernel.org ...
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CentOS/Kernel v3.18/Thunderbolt2

I just got a new SuperMicro box with a AOC-TBT-DSL5320 Thunderbolt2 card pre-installed. I installed CentOS 6.5,ran yum update, and then, because to my understanding at least, thunderbolt support was ...
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MAC to MAC MII interface not working

I have a MAC to MAC MII interface between MPC8569 processor and BCM68610 controller , whose schematic design is followed from here. My linux kernel version is 2.6.32. I want to ping one device from ...
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haproxy - in CentOS is running but the whole directory is no more available and i do not have configuration backup

I had haproxy configured in /var/tmp directory by compiling, i did not had any backup after few months its still running but my /var/tmp/ is having no haproxy anymore. Can anyone please recover it i ...