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

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How to compile video4linux for ARM?

I would like to use a webcam using a Linux over ARM board. Through reading, I have discovered video4linux so I would like to compile it for ARM. My unique notes are: git clone ...
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56 views

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 ...
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38 views

Linux Kernel Firewire Feature: Use Unclear

In the Linux kernel, there is a setting "FireWire SBP-2 fabric module". I do not understand the documentation: Say Y or M here to enable SCSI target functionality over FireWire. This enables you ...
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2answers
417 views

Why is the kernel boot failing?

I am trying to boot from 3.11.1 kernel image on my system having Ubuntu 12.04 (kernel 3.2.0-53) I used make defconfig and then compiled, placed the image in /boot, updated GRUB, and then rebooted. ...
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84 views

centos 6.4 trouble with /dev/pts/ptmx

I have a problem with the server running on CentOS. CentOS has been upgraded to version 6.4 and has all updates. Updates were made according to the official repositories. On the server running the ...
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Why should I build a custom kernel? [closed]

Several of my coworkers have been building custom kernels for their workstations and servers. What advantages/disadvantages are there to building a custom kernel? Why should I build a custom kernel? ...
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182 views

How do I search the linux kernel mailing list archives?

I want to research why a Linux kernel feature appears to be missing from my Linux install by searching the Linux kernel mailing list for recent discussions on the subject. The only site that I've ...
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1answer
91 views

Using qemu to boot OpenSUSE (or any other OS) with custom kernel

I want to run OpenSUSE as guest with a custom kernel image which is on my host machine. I'm trying: $ qemu-system-x86_64 -hda opensuse.img -m 512 -kernel \ ...
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297 views

How is nice working?

sched_setscheduler says : All scheduling is preemptive: if a process with a higher static priority becomes ready to run, the currently running process will be preempted and ...
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224 views

How do I know which kernel configuration option enabled my driver?

TL;DR: when I was trying to compile a driver for USB DAQ device I have reconfigured the kernel. The driver refused to compile under the default distro's kernel but everything works with my tweaked ...
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What does the Windows flag in the Linux logo of kernel 3.11 mean?

I've just installed kernel-3.11.0-1.fc20 for my Fedora 19 installation. During the rebooting progress, I saw the Linux logo with a Windows flag in it, what does it mean? The Fedora 19 is installed ...
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366 views

Boot my kernel in a Virtual Machine?

I'm learning now how to compile and boot linux kernels. Is there a way to boot kernels in a virtual machine, rather than messing my system? I use VMWare Workstation on Windows 8. Can I use that to ...
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260 views

Compile the Ubuntu “Raring” Kernel with the Intel Compiler

Of course, the first question is: why I'm doing this. Just for fun! I'm learning more about Linux kernels and I have a virtual machine that I can replace in 15 minutes. Getting to business, I don't ...
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1answer
168 views

How enable watchdog?

I'm struggling with the watchdog timer (wdt) for a while. I can't get it working. My microcontroller is a AriaG25, based on the AT91SAM925. I have used this tutorial to compile the kernel. The ...
2
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1answer
56 views

Monitoring file reads for cache warming

After adding more memory to my Linux machine I was tempted to use the cache more agressively. The thing is: I boot up my machine, go to bathroom, come back and log in. It takes like half a minute to ...
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57 views

What part of the Linux kernel determines the execution order of userland apps? [closed]

Stripping the source, I can't pinpoint which part of the kernel sets and manages the userland apps, and how it does it. For example, in the Linux main source, is the procedure have options to set ...
2
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1answer
334 views

How to learn kernel programming from the start? [closed]

I have completed my graduation recently. And I have only basic knowledge in C. But I would like to work on the Linux Kernel, and customize it according to my needs. Not only customize I would also ...
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149 views

how to stop kernel threads preempting real time user space processes?

I created some processes in user space and tried to visualize its working in kernelshark with the trace recorded using trace-cmd. But kernel processes like the ones shown below are preempting my ...
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1answer
266 views

CONFIG_RTC_SYSTOHC: how to use the NTP synchronization option in the kernel

I have noticed in kernel 3.10, there is an option CONFIG_RTC_SYSTOHC Device Drivers -> RTC -> Set the RTC time based on NTP synchronization The help says: If you say yes here, the system ...
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2answers
592 views

Which file in kernel specifies fork(), vfork()… to use sys_clone() system call

When ltrace is used for tracing the system calls, I could see that fork() uses sys_clone() rather than sys_fork(). But I couldnt find the linux source where it is defined. My program is ...
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1answer
111 views

How can I override the kernel default options for mount?

I'm struggling with a program that creates a file system in a file and mounts it as a loopback device. The purpose of the program is to create a clone of the root file system and it thinks it's being ...
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90 views

Does a fault in a kernel module necessarily result in a system crash?

Or is it possible to overcome the fault, since the code isn't in the monolithic part of the kernel?
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2k views

Does the kernel have a main() function? [closed]

I am learning device drivers and Kernel programming. According to Jonathan Corbet's book, there is no main() function in device drivers. So I two questions: Why don't we need a main() function in ...
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2answers
1k views

Install kernel-devel of specific version in fedora 19

So I have different "installed" kernel versions from the running kernel version, on my fedora 19 machine. To give a more clear idea, here is my terminal output: [user@home ~]$ uname -r ...
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3answers
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Can I create a virtual ethernet interface named eth0?

This is a rather odd question, because normally it would not make sense to do that. I am running Arch based on the Linux 3.10.5-1 kernel. The system uses the new de-facto naming conventions of ...
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288 views

PC sudden shutdown, Sensors show normal temps, Thermal event interrupts shows 1276

I'm experiencing sudden shutdowns on my Linux systems. Using Ubuntu 12.04, my kernel version is 3.5.0-37-generic #58~precise1-Ubuntu. Running a Acer M5 581t(G) with 6 gigs ram laptop. I have been ...
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1answer
138 views

Generate interrupts for purpose of stress testing

I'm testing the quality of a generated PWM signal on a Raspbery Pi. I would like to test how it behaves if there are lots of interrupts coming. Is there a way to fake interrupts or force 2000 ...
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1answer
465 views

Beaglebone Black Device Tree for LCD4 cape

The device tree for LCD4 cape is located at /lib/firmware/BB-BONE-LCD4-01-00A1.dts When I looked into it, the declaration of those GPIO buttons confuse me. There are five buttons according to ...
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1answer
70 views

Building Linux from Scratch stuck, incompatible sed version? [duplicate]

I am trying to build Linux from Scratch per LFS website While I was able to install all the packages until 6.7.1 without any error, I am stuck at Installation of Linux API headers (This is after I ...
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2answers
201 views

Strange temporary network outage in Linux

I'm facing a very annoying problem that I noticed a week from now and for which I can't find an answer: my network suddenly stops responding, usually coming back exactly 25 seconds later. I was using ...
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2answers
721 views

Linux (debian/testing) cannot boot after installing kernel 3.9.1

Today I wanted to upgrade the kernel on my debian/testing system from 2.6.32-5-686 to 3.9-1-686-pae. So I installed the image by sudo aptitude install linux-image-3.9.1-686-pae (or something like ...
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117 views

What value is stored in linux xtime variable?

Whenever I print the value of /proc/interrupts the value of rtc0 in IRQ8 which is for RTC shows only 1 interrupt on CPU0. I have read that when booting the value of the xtime variable is stored from ...
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1answer
313 views

Why CONFIG_NO_HZ is not set by default

In the Linux Kernel CONFIG_NO_HZ is not set. But an initial reading suggests that setting that option would be nice from a performance point of view. But reading some posts like this made me think ...
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83 views

Why can't new versions of kernel solve the backlight problem?

Currently I am using Linux 3.8.0-27-generic kernel on my Samsung laptop. I replaced grub configuration file with the following text to make backlight control work: GRUB_CMDLINE_LINUX_DEFAULT="quiet ...
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1answer
737 views

What is meant by interrupt remapping in Linux?

Can anyone explain what the interrupt remapping is? Would turning this feature off in the Linux kernel cause any problems, or bring any benefits?
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1answer
138 views

Efficiency of Linux Kernel [closed]

In a documentary, Linus Torvalds says that even in the future, if anyone wishes to make a new OS from the scratch, they could use the Kernel which he wrote. It was very inspiring. Is it true that ...
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488 views

Can system calls be interrupted?

Please comment on the following sentence: On the standard Linux kernel without the rt patch, interrupts can't interrupt ongoing system calls. The reason why our machine doesn't stop working ...
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1answer
175 views

Are time interrupts always followed by a scheduler call?

When a timer interrupt occurred the ISR is called to service the interrupt. Is it okay to assume that every timer interrupt ends with a call to the scheduler on which process should continue running ...
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1answer
45 views

CentOS - acts abnormal every week and causes my whole setup to be down, how can I rollback / restore back to one week?

I have CentOS and Red hat enterprise Linux running, where I have now working Google Apps Engine and related other Python web applications. Every week or depending on any Google Apps Engine latest ...
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68 views

boot updated kernel image on beagleboard

Boot updated kernel image on beagleboard. I had installed a kernel on Beagle-board to update image of kernel to it. I've used this command: $ sudo apt-get install linux-image-3.2.0.49-omap It ...
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1answer
419 views

What are PCI quirks?

I hear a lot about PCI quirks when reading about the Linux kernel, but no website explains or defines PCI quirks. What are PCI quirks?
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How can I know if the current kernel was compiled with a certain option enabled?

Is there a way to know if the kernel was compiled with a certain option activated (i.e. CONFIG_PROC_EVENTS=y) without having to pull out the kernel sources package and looking in the config file?
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to update kernel on Beagleboard

i had compile a kernel for beagle-board with kernel version 3.6.8.x4 with 12.04.1 LTS but after recompile kernel (3.10.1 stable) in this process i just copying the uImage into boot of rootfs section ...
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Will there be any security problem to permit non-root user set up a loopback devices?

if the user has full access to the image file (iso or disk image), will there be any security problem to permit him set up a loopback device backed by this file ? % ls -al /dev/loop* ...
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216 views

Allocated Memory difference in xen guests after using Linux 3+ kernel [closed]

Can someone explain to me why there is a memory difference in Guests with the same configuration? Hypervisor: xen 4.2 64 bit VM1: Centos 5.7 with 2.6.18-274.el5xen Assigned memory from xen is ...
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63 views

Significance of certain folders in linux kernel tree

While going through Linux Kernel Source tree, found certain folders, explanation of which was not seen in the popular sites. Could someone tell why these folders are there like: block - This is not ...
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configure allowed_tcp_congestion_control via config files in linux kernel

I am trying to come up with a custom set of TCP congestion control variants as part of the tcp_allowed_congestion_control. I do have multiple variants on my tcp_available_congestion_control list but ...
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1answer
1k views

“sync” before drop_caches,is it necessary?

I have read a lot of docs saying, it is good idea to do a sync before doing echo [1,2,3] > /proc/sys/vm/drop_caches. I am not able to understand why it is needed, drop_cache is a non-destructive ...
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1answer
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what is the linux boot param “memmap” equivalent in freebsd

In linux kernel, there is an option to reserve a portion of system ram i.e memmap=512M$2G (boot param) Here 512M starting from 2G would be reserved and not available to OS What is the equivalent in ...
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Resuming the Linux Kernel Configuration

I am configuring a Linux kernel before I compile the code. However, after I was thirty minutes into answering the many questions concerning various kernel settings, I accidentally pressed Ctrl+C. I do ...