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

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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
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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1answer
190 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
750 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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51 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 ...
4
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1answer
122 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
103 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
85 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 ...
7
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1answer
209 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 ...
5
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2answers
385 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
103 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
448 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
911 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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0answers
70 views

Shared memory counted as cached

When i start my application that allocates about 5GB of shared memory, i instantly see that the the cache is up by 5GB. Why is the application shared memory is counted as also as cached memory? ...
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2answers
86 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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2answers
307 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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755 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
483 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
183 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
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
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1answer
166 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
236 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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1answer
190 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
233 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
1k 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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91 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
2k 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
186 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
107 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
385 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
137 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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40 views

Kernel dependency on Grub in LinuxMint

I have several linux OS's on my laptop the main one being Ubuntu which I used to boot the other OS's with. I recently had to reinstall Mint Cinnamon, during the installation grub was installed ...
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63 views

Are these memory leaks or is it normal?

I want to find out if there are memory leaks in my kernel. First log: http://pastebin.com/wD2Bhduz Second log: http://pastebin.com/ZWhr7T7S Memory increases for example in UDPv6, cfq_io_context, ...
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1answer
1k 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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111 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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123 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
138 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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264 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
2k 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
120 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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42 views

Is ZONE_NORMAL mapped on the kernel space only?

In several textbooks I've stumbled upon a strange phrase, that "if the amount of physical RAM available is small, the ZONE_HIGH might not exist at all and all the memory would belong to ZONE_NORMAL". ...
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1answer
3k 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
511 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
505 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 ...
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1answer
332 views

Can kexec be built to a standalone binary, to be used where kexec was not built into the kernel?

I have remote embedded Linux devices I am trying to update to a new kernel without having to physically access. However, the command line options they boot with make one of the MTDs read only - I ...
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2answers
2k views

How to blacklist a correct bad RAM sector according to MemTest86+ error indication?

MemTest86+ (the version included with Ubuntu 13.04) says Failing address: 002f796c48 - 759.5 MB What should I specify in the memmap kernel parameter to bypass this area? I've tried running ...
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3answers
106 views

What considerations need to be made when choosing the version of kernel for an embedded device?

I have used buildroot to successfully create a kernel, root file system and cross-compilers to enable me to write application code to run on an embedded device. Currently I have no need to write ...
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1answer
240 views

debian cannot install kernel source

I want to use debian linux for my laptop again. So I took my old debian 6.0 cds and installed it. From the last time I know, that I have to build the driver for my Atheros AR8151 Gigabit Ethernet ...
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366 views

*ERROR* timed out waiting for panel to power on

I'm using Ubuntu 13.04 on Asus VX6 (1.8GHz Atom - 2 cores, optimus nVidia ION) with Kernel 3.9.0. When I start my system I get this error: [ 15.728106] [drm:intel_enable_lvds] *ERROR* timed out ...
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60 views

Decreasing mouse sensitivity at kernel level

I have developed a custom-GUI Server, which runs on virtual console of Linux.For mouse-handling purpose, it reads the mouse device file /dev/input/mice and retrieves the event data and updates ...