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

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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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0answers
189 views

Linux server crash (kernel NULL pointer dereference + soft lockup - CPU#1 stuck)

I have a Linux 3.2.0-4-amd64 #1 SMP Debian 3.2.46-1 x86_64 GNU/Linux server that keeps crashing, usually once every 24-72 hours. I'm running lighttpd, mysql, haproxy and a couple of always-running ...
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2answers
569 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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1answer
172 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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1answer
1k views

Running make with vermagic kernel string with parentheses causes /bin/sh syntax error

I am on Ubuntu Server 12.04 x86_64 and I need to build Android CyanogenMod 7.2 kernel module. My phone has custom ROM and a patched kernel: adb shell cat /proc/version yields Linux version ...
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1answer
158 views

proc/sys/vm/flush_mmap_pages missing in 3.9 kernel, how to get it?

There was an option in redHat 5.2 called flush_mmap_pages, I could set this to zero and that would turn of writing dirty pages from a mapped memory file (so I can do it myself when I want to). However ...
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3answers
1k views

How can I create my own distro and include a custom kernel & packages? [closed]

I wanted to know how to add packages to the Linux kernel and then package it to a ISO or CD for friends. Thanks in advance and please don't point me to LFS - Linux From Scratch!
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1answer
346 views

DD-WRT on WZR-HP-AG300H: Want XFS support; what firmware has kernel 3.8.13-1?

I installed latest DD-WRT firmware to my wifi router WZR-HP-AG300H. I got the firmware from here (05-27-2013-r21676). I'm currently trying to install XFS file system support because my USB hard disk ...
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3answers
79 views

Contents of stack area of a process

I've been going through some Unix text books and I can't have a clear picture on the contents of the stack area of the process. Can anyone please explain or point out some references?
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234 views

Why there are so many problems with the overheating and fan speed when installing Linux? [closed]

I don't understand it. Almost every 10th or 20th question is about fan or overheating or that the fan is too loud and the speed too big etc. And these questions are not only about laptops but often ...
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1answer
185 views

Linux signals logger

I'm looking for a signals logger for the Linux kernel, without patching of kernel. I found many articles with patching, but I am not interested in that. I'm running default Ubuntu 13.04. # uname -a ...
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268 views

How are drivers for peripheral hardware installed in Linux?

I have acquired a new wireless keyboard, and I've tested it out on both a Windows and a Linux box. It worked on both, but with an initial difference - Windows took a minute or two, to look up the ...
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1answer
71 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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1answer
471 views

removing kernel modules not working for some modules [closed]

unfortunately i couldnt install a machine with minimal installation as a virtual machine ,so i am trying to prevent loading of unwanted modules from kernel using blacklist file. Added following to ...
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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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0answers
65 views

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
144 views

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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1answer
163 views

apt-get purge <packages> works fine, aptitude still has <packages> marked as installed and reinstalls them

I've created a Rubygem to help with removing old kernels that have built up over years and are eating disk space. (My laptop had 19 kernels on it alone, and on a small SSD...) I want to use apt-get ...
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2answers
95 views

Making a process read a different file for the same filename

I have an application that reads a file. Let's call it processname and the file ~/.configuration. When processname runs it always reads ~/.configuration and can't be configured differently. There are ...
8
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1answer
252 views

How do I prevent system information from being displayed on a terminal?

I'm working on a curses GUI that is supposed to start up automatically on boot-up in the default linux terminal (I have no X server installed). I have this working great, but I have a problem where ...
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2answers
646 views

My process was killed but I cannot understand the kernel notice

I have a custom application running on an embedded x86 setup (built using buildroot and uClibc). The application has been running fine but this morning when I returned to work I discovered my process ...
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1answer
134 views

How are username, date and time are registered in kernel

How is the date and time of kernel compilation registered in kernel image? cat /proc/sys/kernel/version #35~precise1-Ubuntu SMP Fri Jan 25 17:15:33 UTC 2013
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2answers
2k views

Change the size of my memory pages?

I would like to change my kernel's page size from 4KB to 4MB as I have had a large addition of RAM to my computer and I am never running out of anymore. The idea is that programs requiring large ...
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1answer
3k views

ulimit & rlimit in Linux, are they the same thing?

I see people use the terms ulimit & rlimit interchangeably, can I say they are referring to the same thing?
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106 views

Download the Complete Linux Kernel Collection

I am wanting to download EVERY version of the Linux kernel as source code, Debian files, and RPM files. Where can I find a single site where I can download them all at once? If that is not possible, I ...
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675 views

Enabling UTS Namespaces in the Linux Kernel

When configuring the Linux kernel, what are the advantages and disadvantages of enabling UTS namespaces? Would the new system be harmed if UTS namespaces were disabled?
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4k views

Understanding RCU when Configuring the Linux Kernel

I am configuring the Linux kernel version 3.9.4. I am being asked questions about RCU (seen below). Specifically, what are each of these and what are the advantages and disadvantages of enabling or ...
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1answer
880 views

Why does building an Android kernel need a toolchain, but compiling the entire source does not?

As seen here, compiling the Android kernel requires a prebuilt GCC toolchain (or the equivalent from the Android NDK). Cross-compilation makes sense; we are compiling code for a device with a ...
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3answers
1k views

cant compile install and Configure any linux kernel in debian 7

I followed these steps from the link: (http://www.howopensource.com/2011/08/how-to-compile-and-install-linux-kernel-3-0-in-ubuntu-11-04-10-10-and-10-04/) but these commands don't work: sudo make ...
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1answer
282 views

init: is it a user thread or a kernel thread?

init is the first task executed after kernel is loaded, right? Then who is its owner. also I can see [swapper/0] [swapper/1] ..... [swapper/7] having pid 0 PID PPID CPU TASK ST %MEM ...
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1answer
448 views

Cannot mount eCryptfs

I tried to install eCryptfs on my server to open an eCryptfs I did on my home computer. I got these errors. $ sudo mount -t ecryptfs /home/(place)/enc/ /home/(place)/enc/ Unable to get the ...
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318 views

What does the “00:00:00” timestamp mean in kern.log?

I'm looking for causes of a particular problem in kern.log. There are many entries with a 00:00:00 timestamp: Jun 11 00:00:00 mymachine kernel: [ 0.000000] Initializing cgroup subsys cpusetJun 11 ...
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1answer
404 views

How can I prevent drivers from binding USB devices on a certain bus?

I have a setup with two Logitech Unifying receivers, each receiver has a keyboard bound to it. One of the receiver is to be used by the physical machine to which the devices are connected, the other ...
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1answer
2k views

What is TX status timeout and do I have to worry about it?

Recently, after performing a routine software upgrade, I notice a huge surge in the number of warnings from the kernel that goes like this: warning kern [10839.717480] phy0 -> rt2800usb_txdone: ...
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1answer
105 views

Kernelpanic Fedora 18 with kernel 3.9.2-200

Since upgrading to kernel 3.9 I now get this error every time at start up: BUG: unable to handle kernel NULL pointer dereferences at (null) IP[<ffff8800ca93bfcd>] 0xffff8800ca93bfcc PGD 0 ...
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1answer
7k views

using devtmpfs for /dev

I have noticed the following option in the kernel: CONFIG_DEVTMPFS Device Drivers -> Generic Driver Options -> Maintain devtmpfs to mount at /dev And I see that it is enabled by default in ...
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2answers
202 views

Using newest kernel version on an older system

I always compile my own kernel, and therefore I am not reliant on the distribution kernel (in my case Debian). I have always wondered, whether there is an optimal combination of userspace and ...
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1answer
124 views

Where can I find documentation or source code for udev properties?

Specifically, I've been trying to find what the possible values are for the property UDISKS_PARTITION_FLAGS. It seems to be set to "boot" if the partition has the boot/active flag set, and unset if ...
2
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1answer
471 views

Kernel panic in Fedora 18 after updating to kernel-3.9

I'm really a beginner in Linux, I've installed Fedora 18 and did yum update to update my system. I got a bunch of updates (around 350 MB download), among them is kernel-3.9.4-200.fc18.x86_64. Now, ...
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4answers
153 views

How to make sure, that certain functionality (like Alt+Ctrl+F1 switching into tty) is available in havily swapping system?

At the moment, when I accidentally launch application that eats a lot of memory (that causes system to heavily swap), the system become so unresponsive (waiting hours just to see the mouse move/or ...
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1answer
3k views

How do pdflush, kjournald, swapd, etc interoperate?

Recently saw a question that sparked this thought. Couldn't really find an answer here or via the Google machine. Basically, I'm interested in knowing how the kernel I/O architecture is layered. For ...
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2answers
243 views

obtaining kernel build tree

Could anyone explain me what the kernel build tree is? What files does it include? How can I obtain it from a cross-compiled kernel source (e.g. 3.4.0)?
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2answers
212 views

What does longterm mean on kernel.org?

It's fairly easy to understand EOL, mainline and stable kernel, but I'm not sure about longterm here, What does it mean, or how does it differ from stable kernel?
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1answer
273 views

compressed and uncompressed kernel on an embedded device

I have been using several different embedded boards that store kernel, init files, filesystem, etc. on partitions of a (micro)SD card. I notice in the example usage or instructions that compressed ...
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1answer
550 views

building/compiling kernel headers

I am compiling kernel 3.4 and 3.8 for different target devices. I would like to install compat wireless driver which requires kernel header. Could anyone tell me how I can compile/build the kernel ...
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1answer
4k views

Problem compiling a driver : “No rule to make target”

First of all I am running a CentOS 6.4 installation. My computer is a laptop and I am trying to install the drivers for my ethernet card, because this week end I lost my ability to connect to the ...
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1answer
208 views

Virtual mouse driver, possible X11 problems

I created virtual mouse driver according to Essential Linux Device Drivers book. After I wrote coordinates echo x y > /sys/ ... /coordinates into sysfs node, my program generates event packets ...
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1answer
6k views

Excluding kernel modules through /etc/modprobe.d/blacklist.conf does not work

I don't want to load the kernel module nouveau on my debian box at startup, so I put the following in /etc/modprobe.d/blacklist.conf: blacklist ttm blacklist drm blacklist nouveau I even did a ...
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1answer
1k views

What is user address space and what is it's purpose?

I am reading about processes. I came across a topic "How a process is created" wherein I encountered the following :- The process image as viewed by the kernel runs in its own user address space ...
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1answer
998 views

Assembly files in obj-m list when building kernel modules

I'm trying to build kexec as a module, but I'm running into a weird problem. My obj-m is: obj-m += kexec.o machine_kexec.o relocate_kernel.o When I run the makefile, it complains that there's "no ...