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

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Change device framebuffer to use overlay layer

I'm using atmel-hlcdc driver to control a LCD panel and an application uses the /dev/fb0 framebuffer created by the driver. The display works fine except that the panel's standard orientation is ...
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9 views

control and data flow between 2 linux machines [on hold]

I am doing a project on R-car H2(automotive SOC) in Linux platform. I would like to know how the data and control flow between two Linux machines is, if am using two such boards. Can I get the ...
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31 views

Where in GRUB2 source code is the handover/jump to kernel code?

I'm looking for the line of code where GRUB2 finally jumps to kernel code and thus hands over execution? I guess it's in an assembler file since this is very low architecture stuff. I looked at the ...
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1answer
29 views

How to reduce bootup time of linux? [on hold]

First of all, I appreciate for taking times. I have a PC with the following configuration: 1- CPU: Cor2Duo 2- Ram: 2 GB 3- 40 GB HDD I just need serial and network. I don't need Xwindow. I just ...
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1answer
14 views

Kernel panic – not syncing: Fatal machine check on current CPU

In the latest few weeks, my machine rebooted a few times with this kernel panic error. It's a fedora 21, Linux 4 machine on an AMD E-350 APU. I didn't observe any pattern. When I reboot, the BIOS ...
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11 views

Detecting Hardware of the Dyconn Dubbler Dock

I purchase USB3 dual-hard-drive docking station from Fry Electronics called the Dyconn Dubbler Dock. When I plug this device into an Ubuntu Linux 15.04 laptop (kernel: 3.19.0-26-generic), I see no ...
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31 views

What does raw_spinlock mean? [closed]

I was studying struct raw_spinlock which is in the /usr/src/linux/include/linux/spinlock_types.h was like this: typedef struct raw_spinlock { arch_spinlock_t raw_lock; #ifdef ...
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1answer
12 views

How to make SysRq working on laptop?

My /proc/sys/kernel/sysrq contains the number 502, but Alt+SysRq+... seems not to work on my HP Pavilion laptop. How can I fix that? Update 1: By the way: neither my print-screen-key nor any other ...
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1answer
15 views

compling kernels for armhf

I am trying to compile my own kernel but I am having some issues with understanding. I am using the latest kernel available from kernel.org. My issue is at current: I have zero clue on what options ...
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1answer
48 views

Downgrade Kali Linux

I have upgraded my system to KALI Sana 2.0 and kernel 4.0.0-Kali1-amd64. Previously I had the version kali-linux 1.1.0 and kernel 3.18-Kali1-amd64. The reason I want to downgrade is that Kali Sana ...
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3 views

usb_buffer_alloc, kmalloc, usb_alloc_coherent error writing USB Device Driver [migrated]

I'm writing a USB Device Driver for simple communication with an FPGA (UART / USB) and I intend to end this available for use in the Linux community. Introduction to the problem: I wrote my code and ...
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7 views

Registering virtual SPI master device

I need to create a virtual SPI master device. Having a proprietary solution that communicates directly with a sensor using SPI I want to move the sensor away. To do so I want to create a kernel ...
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3answers
274 views

Everything is a file?

In Linux, every single entity is considered as FILE. If I do vim <cd-Name> then, vim will open the directory content into it's editor, because, it do not differentiate between file and ...
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0answers
7 views

How to use RTNETLINK in kernel module/kernel space to extract routing table?

I want to extract routing table information in kernel module using Netlink sockets? Is it possible? I know that in user space we can do that. Regards
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18 views

What does Linux wait for when switches from Xorg to text console?

Sometimes my Xorg hangs and locks the console dead, with a “stale frame” of GUI on the monitor. Hardware and driver-related problems are likely (see here for description of particular configuration), ...
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1answer
11 views

How download complete patch series from patchwork?

I want to download the patch series RFC PATCH 00/26 i.MX5/6 IPUv3 CSI/IC In patchwork I can get access to individual patches https://patchwork.linuxtv.org/patch/24331/. But downloading 26 patches and ...
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1answer
15 views

Why is debug_putstr() not being printed during boot?

I'm asking myself why debug_putstr() in arch/x86/boot/compressed/misc.c is not being printed during x86 boot phase, though it is configured to do so with GRUB_CMDLINE_LINUX_DEFAULT="". On other ...
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17 views

check-config errors on Linux 3.19.0 kernel, configured under Ubuntu 15.04 x86-64

I'm new to configuring Linux kernels, and am receiving the following errors when running config-check: check-config: /tmp/tmp.tnqExc0fHn/CONFIGS/amd64-config.flavour.generic: loading config ...
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0answers
13 views

Best way to approach HID_MAX_USAGES kernel errors?

This is an issue I have for the second time now: basically, an USB based device reports some wrong numbers for "HID_MAX_USAGES", resulting in the kernel giving an error message and the device not ...
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2answers
37 views

Compiling Kernel : Unable to locate ncurses

I am trying to compile the kernel. I downloaded the source . When I tried 'make menucionfig'. I got following result : * Unable to find the ncurses libraries or the * required header files. * 'make ...
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5answers
114 views

Is there a plain GNU/Linux OS?

I'm currently looking at all the different Linux distros and can't seem to find the original GNU/Linux OS. Apparently there is a GNU System which combined the GNU project with the Linux kernel. How do ...
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Kernel - Measuring the rate of timer interrupts

I am working on optimizing kernels of my boxes for telephony, which involves (among other things) adjusting the HZ rate and the preemption model. Initially the kernel was compiled with the default ...
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.config not getting updated after modification to tegra3_android_defconfig

.config not getting updated after modification to tegra3_android_defconfig After adding a module(MODULE_XX_CONFIG=y) inside tegra3_android_defconfig, I did "make tegra3_android_defconfig" though the ...
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0answers
7 views

Using two memory controllers with SPARSE_MEM on AT91SAM9G45

There are lot posts on this problem in google, but I have tried all the solutions but they are not working for me, so I'm posting here… I am working with AT91BootStarp 3.5.9 with linux kernel 3.6.9. ...
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2answers
189 views

What files does the Linux kernel access?

/init during early userspace, /sbin/init, and /sbin/request-key are three files that the Linux kernel accesses (and they are all executables). Are there any other files, possibly non-executable ones, ...
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6answers
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Why is the Linux kernel 15+ million lines of code? [closed]

What are the contents of this monolithic code base? I understand processor architecture support, security, and virtualization, but I can't imagine that being more than 600,000 lines or so. What are ...
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58 views

module verification failed: signature and/or > required key missing - tainting kernel

I am a newbie in Linux device drivers. I got some problem after installing the driver, which was written by me. The driver is working fine in all functional aspects, but it is is giving one warning ...
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0answers
10 views

Kernel symbol gets .part suffix

When cross compiling the Linux kernel 3.18.10 the compiler adds a .part.<N> suffix at the end of some symbols (see an example below). The number <N> changes when using different ...
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0answers
16 views

Replacement for cap-bound

We have an old Linux from scratch kernel used in one of our systems, that uses the old cap-bound mechanism (modifying /proc/sys/kernel/cap-bound) to restrict the capabilities of the system. This was ...
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0answers
46 views

Wifi driver on Kernel 4.x

I've upgrade my kernel from 3.19 to 4.1.5 but the Wifi driver don't work. Does anyone know how I can make it work? I've tried a few methods but it doesn't work. First method I've tried was to try ...
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3answers
68 views

How can I verify `nice` is working?

Looking at different jobs running on a system with shared resources, it seems the nice values are being ignored. Many jobs with nice set at 19 are running at 100% cpu load while other many other jobs ...
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Linking shared library in linux kernel [migrated]

I would like to modify the linux kernel. I would like to use functions from a shared library (an .so file) in file kernel/panic.c. Unfortunately I don't know how to compile it. When I put it in ...
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1answer
74 views

CPU warning - abrt-watch-log

I am running a Red Hat Enterprise Linux Server release 7.1 (Maipo) on Intel(R) Xeon(R) CPU X5690 @ 3.47GHz I keep getting this error in abrt-watch-log. root 888 1 0 Aug03 ? ...
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Print kernel memory layout

Userland memory layout can be inspected by looking into /proc/self/maps. I am wondering if there is a similar facility allowing to inspect runtime kernel memory layout?
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1answer
13 views

Do less severe log level INCLUDE more severe log levels?

Will loglevel=7 include the logs, for example, that would be produced by loglevel=0? http://www.makelinux.net/ldd3/chp-4-sect-2
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Unattended build of linux kernel

Goal: I am trying to automate the 4.0.4 kernel build to provision it to multiple machines. Since AUFS no longer ships in "extras" package, I am compiling it as well, and then adding via make ...
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37 views

Where do these boot log entries come from and who creates them?

I'm wondering what kind of code writes these first two lines into /var/log/syslog while booting my machine: Aug 4 10:13:48 HOSTNAME kernel: imklog 5.8.11, log source = /proc/kmsg started. Aug 4 ...
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2answers
228 views

Process which locks up, ignores SIGKILL, is runnable (not a zombie or in uninterruptable sleep). What state is it in?

I have a process which several times now has stopped responding and appears to be completely locking up. It doesn't respond to any attempt at strace or peeking with gdb (gdb just hangs on a wait4() ...
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1answer
23 views

Increasing Kernel Mode Setting (KMS) scrollback buffer size

I'm using Kernel Mode Setting to set my server's tty resolution. I added GRUB_GFXMODE=1280x1024x24,auto to /etc/default/grub, and GRUB_GFXPAYLOAD_LINUX=keep was already there. There's no vga= or ...
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1answer
77 views

Unable to install new kernel in ubuntu server. “gzip: stdout: No space left on device” error even though abundant disk space

I am trying to install a new kernel on Ubuntu Server and I am unable to complete it due to a "gzip: stdout: no space left on device" error. The full error was produced after running sudo make ...
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1answer
36 views

Is it possible to delay booting the system after the user has pressed the power button? [closed]

I want to delay the time to load the kernel after the user has pressed the power button by 10 seconds. Reasons for this is a machine we have built which requires other components to start sending data ...
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2answers
46 views

Uboot pass arguments to kernel!

How uboot can pass command line argument to kernel? I did some googling and got to know that it uses bootargs environment variable.There it was mentioned that setenv bootargs key=value.Since I am ...
2
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1answer
31 views

Recompile kernel without modules that are not currently in use

Is there a neat way of stripping the Linux kernel to only support the devices that are currently in use. After NVIDIA complaining about GCC version mismatch, I decided to recompile the kernel with the ...
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0answers
17 views

What is the Linux scsi mid-layer

In the Linux storage stack there are 3 levels: upper, mid and lower. Therefore, I know what it is in that sense. What I'm hoping someone will know is, what files in the Linux source tree actually ...
3
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1answer
42 views

Kernel address space layout

Userland address space is well documented, which includes segments like heap, stack, .text, .bss, etc. But there is not enough documentation on kernel address space. Since certain virtual address is ...
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Kernel config diffs - better way to maintain

I maintain one Linux distro (LEAF) with multiple kernel targets, so it needs to have multiple kernel configs (one reference config + usual patch files for other targets). But this adds headache on ...
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1answer
73 views

what's difference between src version 3.* and 3.*-generic

In my local Linux/Ubuntu, I have two directories for Linux src /usr/src/linux-3.16.0 /usr/src/linux-3.16.0-generic I found the code in 3.16.0 is much more than that in 3.16.0-generic. I am ...
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2answers
52 views

Wrong eUID in `/proc/PID/status` when SETUID is used

While doing a wargame challenge, I ran into an issue with permissions. The info given by /proc/PID/status is not in adequation with the permissions that should be given to the processus. I am user ...
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0answers
30 views

Debian instance has two Kernels after installing Intel PCIe SSD drivers - one with Black screen

I am using Debian 8 and after installing Intel PCIe ssd drivers I noticed that the are two kernels. The kernel which has the Intel drivers installed does not display the desktop, only a black screen. ...
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1answer
87 views

RAM Disk related questions [duplicate]

there is a developed kernel subsystem that needs a chunk of memory allocated to itself that only it could manipulate this chunk. this memory should be physically contiguous and also it need the access ...