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

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Dracut failure when trying to boot Fedora with Qubes kernel

I would like to boot Fedora 23 Workstation x86_64 with a kernel from QubesOS 3.1. I have copied vmlinuz-4.1.13-9.pvops.qubes.x86_64 and initramfs-4.1.13-9.pvops.qubes.x86_64.img into the /boot ...
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How to Recompiling the Kali Linux Kernel ( real tutorial 4/2016 )? [on hold]

I was follow this tutorial : http://docs.kali.org/development/recompiling-the-kali-linux-kernel , and it not helpful . Basicl I finish in this step: http://imgur.com/a/3AuHs . But in step Configure ...
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What is the correct approach to update linux kernel? [on hold]

Currently I use Ubuntu 14.04, 4.0.0-040000-generic. Hardware: intel i3-6100, motherboard asus b150m-c, video card AMD R7850. I've got an issue with Xorg, which led me to updating video drivers, whose ...
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3answers
31k views

Why is swappiness set to 60 by default?

I just read some stuff about swappiness on Linux. I don't understand why the default is set to 60. According to me this parameter should be set to 10 in order to reduce swap. Swap is on my hard ...
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How filesystem atomically writes a block to disk?

Block is an abstraction provided by filesystem, block size is integer multiples of disk sector size. Suppose a filesystem uses 4K as its block size, and the disk sector size is 512B, when the ...
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1answer
43 views

Designing a new Operation System

I want to design a new OS to learn more about how an OS works. This OS is only for educational purpose and I had a few doubts choosing its kernel. Is there any legal issue for using an Ubuntu ...
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350 views

The meaning of Linux Kernel bug output

I have a quick, (maybe naive),question about Linux kernel's output. When I issue a command, the system (Ubuntu 12.04) freezes, the serial port output of this system is as follows: [ 373.805067] BUG: ...
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462 views

What does this key code qualifier mean?

I know that in general this means that I have a "bad disk". But I'm after a more specific reason for why I am getting these messages from the kernel: sd 15:0:0:0: [sda] Attached SCSI disk sd ...
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2answers
334 views

What causes the ata exceptions in my syslog and how to solve them

I have a new system with debian (omv) a SSD hard drive for the OS and a software RAID 6 for the data. I only saw now that I have very regular exceptions in my syslog. I'm worried now, what could ...
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Having a bad time installing Ubuntu

So, I recently upgraded my motherboard and processor. Windows was a real pain to me so I decided to go with Ubuntu. However, I ran into more than a few problems with my installation: When I tried ...
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new kernel compile - error on bootup - Could not find overlay

I was compiling the kernel using slackware-current, the latest version of the kernel, 4.3.3, also tried 4.4-rc5, and ran into this error on bootup Could not find overlay #6 ### dt-test ### of ...
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1answer
27 views

Error on enabled probe: syscall::open_nocancel:entry): invalid user access in action #2 at DIF

I've the following one-liner to show files opened by process: sudo dtrace -n 'syscall::open*:entry { printf("%s %s",execname,copyinstr(arg0)); }' however I've plenty of repeated errors such as: ...
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4answers
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running kernel on QEMU

I face this message: Failed to execute /initKernel panic - not syncing: no init found. Try passing init=option to kernel. I am using this command line: qemu-system-x86_64 -hda disk.img -kernel ...
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Home directory does not mount on kernel update

My home directory will not mount on booting with new linux kernel. Previously, my home directory has been mounted automatically from a network device. I updated my kernel to 4.6.0 from the git ...
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2answers
557 views

Are there any Workload Management subsystems for Linux?

Asked this on superuser, got no response: Can anyone tell me of the status/state of WLM (Workload Management) kernel scheduler systems in Linux? Alternatively, any user-space process goal-based load ...
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1answer
376 views

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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1answer
849 views

custom kernel and firmware loading

After I have compiled my kernel, and when I type make modules_install, not only are the modules copied into /lib/modules/ but also firmware is copied into /lib/firmware/. The following is the end of ...
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Empty kernel directory but kernel-headers are installed

Host - Windows 7 Guest - CentOS I am trying to install kernel-headers using yum since during the installation of vmware-tools I get a message asking for the path to the kernel header files for the ...
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3answers
9k views

Set default kernel in GRUB

How can I pick which kernel GRUB2 should load by default? I recently installed a the linux realtime kernel and now it loads by default. I'd like to load the regular one by default. So far I only ...
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14 views

How do I enable higher C-states on Xeon 1505m with Linux?

I am running a Lenovo ThinkPad P70 with a Xeon E3-1505M v5. Installed the 201604 Arch, most everything is running well, except power states. The kernel I'm using is 4.5.1-ARCH, but I've also tried 4.6 ...
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1answer
1k views

Scaling issues of i7 3520M with intel_pstate module on Kernel 3.10.0

Few days ago I updated my openSUSE 12.3 system from Kernel 3.9.8-1.gf3348a8-desktop to 3.10.0-1.g3dcd746-desktop and since then, turbo mode of my i7 3520M is enabled by default and it does not ...
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How do I compute the angle of the 2D 3 points ? [[ In kernel space]

I 'm looking at the touch driver 's Kennel. Sometimes a touch is bouncing County singah appear. Collected by recruiting three points 'm trying to calculate the angle between . But there is no such ...
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1answer
37 views

How to use the proper video driver on Scientific Linux 6 for Display Port screens?

I am working with (one of) my workstation(s) working under Scientific Linux 6, so, basically a quite old version of Red Hat Enterprise Linux. I would need to use 2 screens, but only have 2 DisplayPort ...
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How to support 64-bit times on a 32-bit Linux platform

I need to support 64-bit times on a 32-bit ARM embedded Linux system based on kernel version 4.1. I use clock_gettime() and clock_settime() to get/set the time, but they are limited to 32-bit seconds ...
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Kernel problem after upgrading to 4.5.1

I updated my kernel from 3.19 to 4.5.1 (which is the latest ubuntu-based upgrade), and when I rebooted, I saw an alert: Alert! /dev/disk/by-uuid/xxxxxxxxxxxxxxxxxxx does not exist! where x's are ...
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979 views

psmouse sync issues!

I have Compaq CQ61-420US (64-bit AMD) laptop with Synaptics touchpad checked using $ egrep -i 'synap' /proc/bus/input/devices N: Name="SynPS/2 Synaptics TouchPad" But recently after Arch Linux ...
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ALG IPSEC and RSTP

I have linux 3.18. my Linux is installet on a router. in this router I activate a NAT from the wan side. Does this Linux support ALG of IPSEC and RSTP ?
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Installing Wireless Adapter (GWU625 v1.1) On Modern Fedora OS

I am trying to install the driver to GWU625 v1.1. You can download it here for what it is worth. It is recommended for Fedora v10 but I want a to run an OS which is supported by the people who ...
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Centos kernel-devel 4.x kernel

I'm under directive to use Centos with kernel 4.x due to a customer requirement I updated my Centos kernel to 4.5..., Now when I try to build my kernel driver I get an error saying build is not ...
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1answer
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Are IPv6 link-local addresses assigned by the kernel or by a userspace program

When IPv6 is enabled for an interface, it will get a link-local address assigned automatically based on the MAC of the network interface. But who assigns this address? Is it done in the kernel, or by ...
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What is kernel Space and User space. [duplicate]

what is Kernel space ? i want to understand it and same with User space and what is the diff between them
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764 views

Do I have to compile the kernel every time, even for a small change?

In my project I configure the kernel (2.6.32) in block/ioctl.c. We all know that kernel compiling and building takes few hours. Even for a small change, I'm compiling from scratch. So is there any way ...
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1answer
572 views

Linux distro with PREEMPT_RT patch

I want to know if there is any Linux distribution with PREEMPT_RT kernel patch? If not, is there any good tutorial on how to patch and compile a kernel with RT patch and how can I create kind of a ...
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1answer
26 views

How to block drivers built-into Kernel, i.e. drivers who are not a module

I configured and compiled Linux kernel with nouveau driver built-into kernel, i.e. with <*> as opposed to <M> when doing make menuconfig inside Linux kernel source directory. Now, I ...
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Kdump.service FAILED centOS 7

I'm having CentOS 7 64 installed on my desktop. After recent system update, I am getting below error while booting the CentOS 7. Some time system is able to boot and I can work on it. but it gives ...
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1answer
44 views

How to simulate GPU hardware failure?

I'm doing some research that has to do with GPGPU resilience with NVIDIA graphics cards and I've been looking for a way to, as accurately as possible, simulate hardware failure. I know about ...
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Debian Wheezy VirtualBox error: Kernel driver not installed

Installed virtualbox on wheezy via apt, while I try to launch my VM a message error appears: The virtual machine 'Windows 7' has terminated unexpectedly during startup with exit code 1 (0x1)." ...
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How to compile custom kernel for Raspberry Pi

I'm trying to run the Ubuntu 14 Raspberry Pi ARM image in QEMU, and for that I need the kernel that matches the version used in the image. If I mount the image and run file vmlinuz I see: vmlinuz: ...
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1answer
3k views

Setting up HDMI output from Linux console

I am currently running Debian Wheezy on a HP Microserver N54L with an AMD Radeon 5450 video card. I would like to be able to play audio from the console through the HDMI port of my video card and ...
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3answers
35 views

Filesystem kernel API

Assuming that all filesystems are specific, how tools like ls, touch, cat, etc interacting with them? I suppose that 'ls' doesn't know specifics about btrfs for example, but it reads directory entries ...
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2answers
41 views

How is redirection implemented?

Is redirection a concept of the shell, not of the OS kernel? How is redirection implemented in terms of system calls? Is redirection implemented similarly to pipe?
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38 views

Cleaning swap space while running

I have a theoretical question, What would happen if I clean up all the swap space while running, Would the operating system crash because of page faults that would happen in the kernel?
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2answers
68 views

Change Wireless adapter driver in Linux

I am using openSUSE Tumbleweed. I've bought a new PCI-E Wireless card, that supports 5G WiFi (Intel 5100 AGN). It doesn't show up in lspci and even if I take old adapter out it still cannot see my ...
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21 views

m2c : Command not found

I want to experiment on DCTCP protocol. For that I am trying to compile linux kernel version 3.2.18 and include a dctcp patch for that. I am following the directions given here. While I am compiling ...
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1answer
29 views

Uprobes Status on the present linux kernel

I know uprobes was introduced on kernel 3.5 has it survived or is it dropped, is it still available on kernel 4.x
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minimum time between two consecutive UDP packets

I am interested in developing a C application which sends UDP packets with minimum delay between two consecutive packets. Is it possible to "book" the UDP stack with the NIC hardware from user space ...
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Linux usb-drive write cache

Is there any way to change the way the Linux kernel handles external storage and the external storage cache? Every time I copy something to it, the copy process seen from userspace seems really fast. ...
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2answers
1k views

Benefiting of sched_autogroup_enabled on the desktop

I am running a 2.6.37 kernel with sched_autogroup_enabled set to 1. I am not certain that I am seeing the benefits of this patch since: I am launching my applications from the desktop; applications ...
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it terms of terminology is there an accepted difference between a kernel agent and a kernel module or a kernel driver?

In terms of terminology is there an accepted difference between the concept of a kernel agent, kernel module, or a kernel driver?
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2k views

Why does the linux kernel use linux-libre code to get rid of binary blobs?

I ask this question because I'm curious as to whether there is some sort of performance advantage offered from the binary blobs that are in the Linux kernel. Since many of these blobs have been ...