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

learn more… | top users | synonyms

5
votes
2answers
77 views

Linux kernel manual build: resulting binary is 10 times larger than precompiled binaries

I'm using Linux Mint 13 MATE 32bit, I'm trying to build the kernel (primarily for experience and for fun). For now, I like to build it with the same configuration as precompiled kernel, so firstly ...
0
votes
0answers
17 views

Custom kernel for Intel z2760 CPU [on hold]

A friend of mine wants to install Linux on his tablet with a z2760 CPU from Intel, Googling it gives some forum topics of people saying there Kernel freezes during boot. Is there someone who managed ...
0
votes
2answers
35 views

installing grub and a working kernel over an old and broken debian system

I have an old debian system, which I always have been able to upgrade over the years. I had installed an old kernel, compiled by me from sources. After my last dist-upgrade (using testing ...
-2
votes
0answers
34 views

Developing Linux Kernel From Scratch - Step by Step [on hold]

I would like to develop my own Linux Kernel. I am pursuing my Final Year in my Bachelor's Degree. I have undergone 2 courses based on this (Operating Systems, reference book is Silberschatz and Unix ...
2
votes
1answer
23 views

How do you patch a kernel? [duplicate]

I got diff text from lkml how do I patch it into a kernel source? I am very new to compiling kernels, and I couldn't find decent sources online I am using debian if it is relevant
5
votes
2answers
3k views

How to build a custom kernel? [duplicate]

I want to test an (upstream) custom kernel on Fedora. The plan so far is: use a recent fedora config as starting point, e.g. /boot/config-3.6.6-1.fc17.x86_64 lookup build dependencies lookup right ...
3
votes
2answers
43 views

Questions about kernel releases

Right now there are about 7 (or more) kernels maintained by the Linux Foundation. I was wondering if you could clarify my doubts and answer my questions: Isn't the next kernel's release maintaining ...
0
votes
1answer
18 views

Loginuid, should be allowed to change or not (mutable or not)?

I am trying to configure the linux kernel. I was confused by Make audit loginuid immutable (AUDIT_LOGINUID_IMMUTABLE) [N/y/?]. The help says: +config AUDIT_LOGINUID_IMMUTABLE + bool "Make ...
6
votes
1answer
31 views

How do I know what decompression algorithms are compiled-in into the linux kernel?

If /proc/config.gz is unavailable, how do I know what decompression algorithms the running kernel is capable of using on a compressed cpio initramfs? Is the gzip algorithm always available, even when ...
3
votes
1answer
25 views

How do I find out what filesystem drivers are compiled-in into the linux kernel?

On a running linux system, what is a portable (among linux distributions) way to find out what filesystems the current kernel has compiled-in (not through modules) support for? Consider for example ...
5
votes
2answers
129 views

File handles and filenames

I read this post. Are file descriptors the same as file handle? While trying to configure the linux kernel, it asks open by fhandle syscalls (FHANDLE) [Y/n/?]. Why is this option provided? Does ...
4
votes
2answers
59 views

USB set to /dev/sda instead of /dev/sdb

I've been trying to use a kickstart file to guide the Red Hat installer (RHEL6.5) without user intervention. It correctly looks for the kickstart file in /dev/sdb/fs.cfg, but because the USB is ...
2
votes
0answers
24 views

Enable BFQ in Fedora

I am running Fedora with the stock kernel and I'd like to enable the BFQ disk I/O scheduler, and ideally BFS. I have built my own kernel and that works, though it is a royal pain dealing with the ...
3
votes
0answers
24 views

Kernel bisect: when a patch is failing for a reason other than original bisect purpose, what do you do?

Let's say you're trying to find the cause of a bug between 3.11.0 and 3.12.0. The bug is really difficult to catch, because it may or may not manifest itself over several days of regular workload ...
0
votes
0answers
15 views

The latest stable RT patch version of linux kernel 2.6.31

I want to get the lastest stable RT patch version for linux kernel 2.6.31. But I was confused when looking it up at kernel.org. I saw that: patch-2.6.31.6-rt19.gz last modified was on 10-Nov-2009 ...
8
votes
3answers
473 views

Using real time kernel headers to compile userspace code vs default headers

Per customer requirements, I installed CentOS 5.6 with the default kernel. With this kernel installed, the time.h file includes the #define CLOCK_MONOTONIC. Now, a real-time kernel was installed ...
3
votes
2answers
64 views

Testing the Success of a Congestion Algorithm

How do you test whether a particular congestion algorithm is working for you? I ask because it's not as if I can easily re-create a representative workload for most algorithms. I'm current looking at ...
0
votes
2answers
952 views

How to update CentOS 6.5 to kernel 2.6.32-431?

I need to update my CentOS 6.5 kernel to 2.6.32-431. Running yum clean all && yum update doesn't do it for me. How do I update? And what could be the issue? [root@centos64 ~]# uname -r ...
0
votes
1answer
40 views

aircrack-ng shows negative channel

On many Linux distributions, be it BackTrack, Kali, BackBox, Ubuntu, Mint, etc., whenever I use anything from the aircrack-ng suite my wireless card is shown as channel -1. This problem has been ...
5
votes
2answers
239 views

Linux kernel headers' organization

While I was doing some reading on system calls, I did a search for "syscalls.h" to find the header file in LXR. The search results puzzled me. There is a dozen of "syscalls.h" files coming from ...
3
votes
5answers
4k views

Kernel can't find /dev/sda file during boot

I configured a gentoo kernel (kernel-2.6.36-gentoo-r5), but when I boot it can't mount /dev/sda1: ALERT! /dev/sda1 does not exist . Dropping to a shell . I use the shell to go to the /dev ...
7
votes
3answers
3k views

Why is the theoretical RAM limit for RHEL 6 128 TB and how is this determined?

I'm studying for RHCSA and am confused by a statement I came across in some training material: There is no practical maximum RAM, as theoretically, you could run 128 TB of RAM on RHEL 6. But ...
5
votes
1answer
442 views

In what sense does SATA “talk” SCSI? How much is shared between SCSI and ATA?

This is nothing new to me at least, that SATA actually "talks" SCSI, hence why these SATA devices show up as SCSI devices in Linux. A related question has been asked before, e.g. Why do my SATA ...
1
vote
1answer
46 views

How do I compile source into the kernel?

I want to add and compile my custom application code into my kernel. How should I add my .c and .o files into my kernel 'bin' directory and compile them? I made a hello.c and hello.o file and I want ...
2
votes
2answers
44 views

Linux 2.6.36.4, GCC 4.7.2, getting lots of “variable set but not used” warnings

I am trying to compile the Linux kernel 2.6.36.4 on Linux Mint 14 running a 3.5 kernel by default. Using gcc version 4.7.2. Tried googling it, but didn't quite work out. The warning is: warning: ...
6
votes
1answer
31 views

File backed, locked shared memory and disk interaction

Varnish, a HTTP accelerator, uses a ~80MB file backed SHM log that is mlock()ed into memory. The Varnish docs recommend to store the file on tmpfs to avoid unnecessary disk access. However if the ...
1
vote
0answers
45 views

Installing linux source [closed]

My distro(Crunchbang) was missing the source files and only the header files were present. So I installed the Linux source using: $ sudo apt-get install linux-source After the completion of ...
0
votes
0answers
51 views

inotify does not work with linux kernel 3.4.11

I have a Linux running with kernel 3.4.11. I tried to run inotify-tools, but it does not work (in fact it does not detect the file changes). I checked the .config file of Linux kernel and I found ...
0
votes
0answers
16 views

SLES 10 SP4 - how to get specific kernel source?

I want to look at the kernel source for some specific kernel versions on SLES 10 SP4. I don't want to see just the Linux kernel source, but the one SLES is actually running. Suppose I wanted to get ...
2
votes
0answers
14 views

Virtual kernel memory layout in dmesg linux kernel 2.6.31

I'm working on a embedded linux project for ARM architecture, kernel version is 2.6.31.12-rt21. In dmesg, I cannot see the virtual kernel memory layout like this: virtual kernel memory layout: ...
0
votes
1answer
13 views

kernel config with strange dependancies

I am trying to build the Android Linux kernel from source following this README. The instructions very clearly state: 1.1 Required enabled config options: After building a standard defconfig, ...
0
votes
1answer
35 views

ncurses-devel problems in SuSE Linux Enterprise Desktop 11

Searching on the WEB, I found this tutorial (the only one that has convinced me) for installing a new kernel and I followed the steps provided. But, I got these problems: In the first step I tried ...
1
vote
1answer
45 views

How is 32bit Linux virtual memory structured in relation to PCIe Base Address Registers

I'm working on a Linux system (32 bit, 4GB RAM) and found some contradictory information about memory addressing in Linux. Am I right with this: Only virtual memory has the differentiation between ...
0
votes
0answers
19 views

Calling speaker-test from usermode-helper API

I needed to call come audio-producing applications from kernel in a toy module. In order to test that, I thought of calling speaker-test from a simpler module, but no sound would ever come from it. I ...
1
vote
1answer
316 views

Determine whether kernel built-in driver supports a device

I'm trying to find a way to accurately determine whether all the hardware on some system has a valid driver installed either via a kernel module or built-in to the kernel. I'm working with RHEL 5.5 ...
1
vote
0answers
53 views

DisplayPort and Intel HD cause GPU hangs

My system has problems with the displayport connection. This is indicated by several problems that, at the first glance, do not have anything in common. The reason why I claim DP for beeing the cause, ...
0
votes
2answers
103 views

Linux memory usage?

We have 1TB of memory on a server which hosts an SAP application. When the app is running the memory usage shown in top is around 700GB. When the app is stopped the memory usage shown in top comes ...
0
votes
2answers
394 views

File system CRC check

I know that before running the kernel, u-boot (the boot loader) will check the kernel image CRC. Only if it is correct it will go further, else it will give a "Bad CRC" error. I want to do same thing ...
7
votes
3answers
14k views

Enabling IOMMU in the kernel for graphics card pass-through

Short question: How can I turn on the intel_iommu setting in the Linux kernel? I run a Debian host, using the grub2 bootloader. Documentation I've seen says to edit /boot/grub/menu.lst, which seems ...
14
votes
2answers
2k views

Who is responsible for the Linux kernel?

As of today, there are many Linux distributions like Ubuntu, Fedora, Gentoo, Mint, Debian, etc. These distributions update at different cycles. Ubuntu seems to update its kernel weekly or monthly, ...
3
votes
0answers
537 views

How extended (4MB) and regular (4KB) paging coexist?

On x86 architecture, "Extended paging" allows page frames (physical memory) to be 4 MB instead of 4 KB. The book "Understanding the Linux Kernel, 3rd" at chapter 2 "Memory Addressing", sub-chapter ...
0
votes
2answers
451 views

Error while installing wireless-bcm43142-dkms-6.20.55.19: dependency linux-headers is not satisfiable

I have to install a .deb file with the firmware for the wifi card (This is the name of the file: wireless-bcm43142-dkms-6.20.55.19_amd64.deb; I've downloaded the file from here: ...
1
vote
2answers
22 views

Running assembly program as ring 0

I'm writing an application which reports back readings from CPU temperature sensors, and the fan speed monitor. However, according to the Intel documentation on PECI, the instructions required must be ...
3
votes
0answers
35 views

What's the exact behaviour of the command: ip address change?

I have been fiddling with IPv6 and address lifetimes. I found out that the valid_lft attribute will make a v6-address disappear automagically, if used correctly. To extend an address' lifetime I would ...
3
votes
1answer
47 views

Built the kernel with NFS support but not getting /dev/nfs

I'm trying to build kernel 3.13.9, fetched using apt-get source, and built in a clean debootstrap chroot (both host and chroot being installations of Ubuntu Trusty). My goal is to boot a diskless ...
1
vote
0answers
29 views

tasklet and interrupt handler synchronization [closed]

The things I know about tasklet: Tasklet runs with all interrupt enabled. The tasklet runs in interrupt context. It can't sleep. It runs in atomic way. It has the assurance to be scheduled never ...
1
vote
1answer
2k views

net.ipv4.conf.all.mc_forwarding: why is my access denied?

On Debian 12.04 LTS I am trying to access the key net.ipv4.conf.all.mc_forwarding by doing : sudo sysctl -w net.ipv4.conf.all.mc_forwarding=1 But every time I am doing this, I get the message ...
3
votes
1answer
906 views

Setting CPU governor to on demand or conservative

I'm struggling with cpupower on ArchLinux. I want to set governor to ondemand or even to conservative. First if I do $ sudo cpupower frequency-info --governors, I only get performance powersave. So ...
1
vote
1answer
2k views

Is “sync” before drop_caches 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, since drop_cache is a ...
-1
votes
0answers
11 views

How to use termios and ioctl functions in kernel module? [migrated]

I wrote a kernel module for a touch screen monitor and earlier I used inputattach (written in userspace) to open serial port, set baud rate, control flags, line discipline etc. But now I want to ...