This tag is for questions about the internals of the Linux kernel itself - particularly about use or configuration of kernel modules or drivers.

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312 views

Why is the kernel and the watchdogs consuming all the CPU?

I run a bunch of heavy user space processes on a powerful Xeon machine (32 virtual processors according to /proc/cpuinfo). The CPU load is normally around 30 and the machine feel responsive, but later ...
2
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0answers
80 views

How are ties broken in AuFS with the top-down-parent file creation policy?

The AuFS manual says: Policies for Creating create=tdp | top−down−parent Selects the highest writable branch where the parent dir exists. If the parent dir does not exist on a writable branch, ...
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0answers
148 views

What does the linux kernel/initrd loading time depend on?

I recently updated my Linux kernel from 3.1.10 to 3.5.0. Upon booting with GRUB, I noticed that this kernel (or the initial ramdisk?) takes a much longer time to load (~5-6 s vs. ~1 s with the old ...
2
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0answers
192 views

Capture key events at system level to control e.g. alsamixer

In Linux window managers, it is easy to define actions for key events - e.g. in openbox: <keybind key="XF86AudioRaiseVolume"> <action name="Execute"> <command>amixer set ...
2
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0answers
225 views

Linux kernel 2.6 - layer 7 support?

From what I found on the Internet, Layer7 classifier support is not merged into the current kernel (as of 2.6.39-rc6) and can be achieved with a patch. Is it known when (if ever) the support will be ...
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17 views

How to disable USB Mouse only

I was developing a device driver for a USB mouse which uses the USB HID driver. The problem is that I cannot test out my module as Linux takes over the mouse directly. So how do I find out which ...
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0answers
44 views

Linux - How to list all device nodes using a specific device driver

I know I can see what driver is being used for a device node if I know the major and minor number of the device(see this link). But I want to know if there's a way to list all device nodes that are ...
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60 views

Linux Kernel TCP socket functions

So I have been looking through the Linux Kernel v3.8.0-19-generic source code and I noticed that the proto struct, whose members are virtual functions for socket operations depending on the particular ...
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66 views

getting error while adding a system call

I'm using Ubuntu 12.04(64bit) and installed kernel version linux-2.6.37.3. My device is ASUS x201ev net-book(64 bit). I'm providing the link of procedure i used. i edited unistd_64.h file also and ...
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0answers
80 views

My own linux Chorded keyboard driver and interface to my embedded application

I wan to develop my own keypad driver to my own keypad. I have to used GPIO to identify Key Events and used I2c to get scan code. I am going to develop keypad driver like this. #include ...
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0answers
7 views

How to approach searching for sources of interface unresponsiveness

On Debian Linux: On a relatively powerful machine I ran an update and both the kernel and the window manager got updated to newer version. At that point the machine become noticeably less responsive: ...
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264 views

DKMS failing to complete in Ubuntu 12.04

After my last attempt to run an update with sudo apt-get update; sudo apt-get upgrade I got into a never returning update step (see below). So far I can only Ctrl+C but it will be triggered again ...
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40 views

Who is filling the ELF header

I have ELF file which I dumped using readelf -h filename and I can see the different fields with the some values like entry point address is 0x99cc ,but really want to know from where these values get ...
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0answers
120 views

Installing Kernel 3.5.1 breaks boot up

I have twice tried to update my kernel from 3.2.0.30 to 3.5.1 on my Ubuntu 12.04 32 bit system using two different methods I found via google. In both cases the operation appeared to run flawlessly ...
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0answers
134 views

An error during bochsdbg installation

I want to install bochs which can debug the kernel. First, I download a package, then: tar zxvf bochs-2.4.6.tar.gz<br> cd bochs-2.4.6.<br> ./configure --enable-debugger --enable-disasm ...
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0answers
858 views

Use initrd as root filesystem for network boot

I'm creating a stand-alone set of netboot images based on a LinuxFromScratch installation (7.0, kernel 3.1.0). I want to deploy that image to many diskless clients, but NFS is in my situation not an ...
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783 views

Setting up a Remote Diskless System

I am trying to setup a PXE Boot server with RHEL 6 and am following these directions. Has anyone done this successfully?? I am having various issues. I used the rsync command to copy over the ...
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0answers
97 views

kernel 2.6.36 not booting

I m a newbie to kernel programming. I am trying to boot the kernel 2.6.36 on my ECG machine.It was working perfectly on 2.6.33.2. It is getting stuck on this step: ## Booting kernel from Legacy Image ...
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161 views

Upgrading kernel in live ISO file?

I'm no Linux expert and I need to upgrade the kernel, and some applications, in a Ubuntu live ISO file whose structure looks like this: I've never done this before, and would like to check ...
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0answers
5 views

Mounting HFS+ Franken-file-system created by Mac Partitioner on Powerbook G4 (mount in Debian or OSX)

The ultimate goal here is to copy files from a drive, which was created (as an external backup drive only) on a Powerbook G4 (AluBook). This drive was previously used in Windows XP, and appears to ...
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0answers
18 views

IPsec in the Linux Kernel

I have some issues (questions) related tot the Linux Kernel implementation of IPsec and it's user-space interface. The biggest question is which is the actual official project for the Linux Kernel ...
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0answers
6 views

How to install cached linux debug symbols?

I am doing work which requires downloading and installing debug symbols multiple times for a specific linux kernel i.e: linux-image-3.8.0-26-generic-dbgsym I'm on a fast university fiber network. ...
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23 views

What is the exact difference between the parameters (pgpgin, pswpin) and (pswpout, pgpgout) in /proc/vmstat?

Please note that this question is specific to linux only. And by swap space, I mean the dedicated swap partition. I did google a bit on this, and found these definitions: Paging refers to writing ...
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0answers
15 views

unable to find a suitable fs

I am trying to install edx on a virtual machine. But i am getting problem with apparrmor.When i run command. $ apparmor_parser Warning: unable to find a suitable fs in /proc/mounts, is it ...
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0answers
9 views

Is ramdisk_size still needed with a .cpio initrd?

I'm creating a rescue system with the following two files: rescue.linux (version 3.2) initrd.cpio The initrd.cpio file can be quite large, larger than the default 4MB of a ramdisk. However, it ...
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13 views

kernel configuration: select specific drivers or symbols regardless of dependencies?

Is there a way in "make menuconfig" et al. to start with enabling device drivers that you want included, and have it enable the necessary (dependent) generic options and APIs automatically? As it is, ...
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0answers
17 views

Virtual machines on Secure Boot

I have Fedora 20 installed with Secure Boot. I've been trying to make a virtual machine using OracleVM VirtualBox and VMware Workstation, but none of them work (vmmon couldn't be started). After ...
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0answers
17 views

What HID/Module does Air mouse use in Linux?

I was thinking about developing a module for running a Air Mouse. I am not sure as what module s used to carry out the operation done by air mouse. Is it under HID? (I am talking about a wireless Air ...
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0answers
28 views

How to rewrite ACPI control tables from Linux?

I have a HP Probook 4720s laptop with broken ACPI tables. The fan is always switched off and the computer tends to overheat and shut down. Under Windows I can use a program called RW_Everything to ...
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0answers
15 views

Acpitool no information

When I run as root acpitool I recieved Battery is not present, bailing out. AC adapter : <info not available> Thermal info : <not available> I can understand why all the ...
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0answers
35 views

What is the difference between cat and normal file operations on proc files

I have implemented a ps like utility module for procfs which extracts basic information such as command, pid, tgid etc. I have used the sequence file approach. I am inspecting my proc file using two ...
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64 views

How to install kernel 3.9 in Debian Jessie from repos?

I was wondering if it is possible to install kernel 3.9 in Debian Jessie from repos. A brief check shows that there are only 2.6, 3.2 and 3.13 kernels in repos Compiling my own kernel is the last ...
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0answers
18 views

How can I to update the kernel in my network NAS from Conceptronic: CH3SNAS (same as D-Link DNS-323)?

I have installed Fun_Plug (up to v0.7) and using it for years in my CH3SNAS, following instructions from Uli's web site, but even when the site has new kernel modules for download, I have not been ...
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0answers
325 views

Not enough host controller resources for new device state

I have a debian mint based system where I plug in 16 usb devices. The Kernal is: 3.11.0-12-generic After about 10 or so devices I start to experience problems with connecting new ones. There error ...
0
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0answers
17 views

Need an application that takes a few seconds to test some speed up techniques

there is this ARM9 SAM9G25 embedded device, which I like to improve its performance. I'm using Buildroot 2013.10 to generate the bootable Linux 2.6.39 images. There are some methods I'd like to apply ...
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25 views

Linux: Keypresses missed when typed, possibly IRQ issues?

I have a strange behavior on a Raspberry Pi, running a buildroot'ed Linux kernel 3.13.5. When the system comes under a little load (eg. mpd is running in the background happily playing out some ...
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0answers
62 views

Linux kernel module is not running anymore when switching from mdev to udev

I'm using Buildroot 2013.10 to generate my Linux 2.6.39 Images, with the following Kernel module: void GPIO_LED(void) { printk(" GPIO: set PC8: '0'); at91_set_gpio_value(AT91_PIN_PC8, 1); ...
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33 views

Hardware watchdog only works on one of two almost identical systems

I've got two industrial single board computers which should be identical except for one has a Intel Atom Z510 and the other a Z530 (1.1GHz vs 1.6GHz and Z530 has hyperthreading). I'm pretty sure the ...
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0answers
34 views

why the device file can not be found in init process after kernel booted?

I want to execute a script in init process, and I want it auto restart whenever it is terminated. I put this line in /etc/inittab ::respawn:/root/test.sh and the test.sh contains this line (I ...
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0answers
138 views

Buildroot : how to install generated images on another disk?

I use buildroot to generate linux kernel, rootfs and boot-loader (grub) for i386-i686 architecture. The generated image works with qemu. I have tested with "unetbootin" and "linuxlive usb creator" to ...
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0answers
90 views

Oom-killer (out of memory) with plenty of RAM (?!) - inotify

I'm facing an issue by putting inotify to a huge amount of folder (~2 000 000). I changed the max_user_watches to 8388608 : echo 8388608 > /proc/sys/fs/inotify/max_user_watches To support this ...
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0answers
26 views

What are the basic dependencies in linux to detect and use USB?

What are the basic requirements to detect and mount usb on the Linux platform till now I have found following dependencies : Power up pulse to the pins of USB port in GPIO drivers usb drivers ...
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0answers
134 views

PF_RING on arch linux

I'm currently trying to install PF_RING on my arch linux: http://sourceforge.net/projects/ntop/files/PF_RING/ But when I run make I get the following error: cd kernel; make make[1]: Entering ...
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0answers
26 views

Missed record in GRUB

I did install a new linux kernel from deb packages and run reboot. This new kernel replaced my current one. But the new kernel caused corrupted and it fails on booting (no console and no X... just ...
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0answers
1k views

linux kworker's CPU percentage extremely high

I have a laptop with i7 processor and ATI video card, all the distros I'v installed have a common problem -- there is always a kworker(kernel thread) occupy 40% of the CPU, (i.e. one of the 8 logical ...
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0answers
343 views

bash autocompletion is slow, freezing my desktop

sometimes when working with a custom kernel, pressing tab in the bash autocompletes at a horrible pace. It freezes the whole desktop. Then comes back after awhile. This is the only quirk that I've ...
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0answers
162 views

rtl8111/8168b doesn't work after upgrade linux kernel

my computer has a ethernet controller: realtek semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06) my computer is installed archlinux. Before I upgrade kernel, it ...
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0answers
484 views

Kernel OOM killer been called when plenty of memory left while using malloc

The program is a memory exerciser that request multiple chunks of 512MB to malloc. For some reason the node 0 is been memory exhausted while the others are not been called. MemExerciser cpuset=/ ...
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0answers
181 views

Kernel recompilation: mp-bios error 8254 timer not connected to ioapic

After recompiling my kernel I see this error every time I start linux. Os starts fine but I see it is not stable at all: sometimes it freezes and I can just reboot it. I guess it is because of this ...
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0answers
529 views

Get current thread id in kernel based C code (Linux)

I have a module which is accessed for read/write operations to a proc file. I know I can get current process id using current->pid, but is there a way to get the current thread id that is accessing ...