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

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1answer
561 views

Calls to sync/fsync slow down after 30 minutes uptime

After 30 minutes of uptime using Ubuntu 14.04 with a hybrid SSD I see many processes blocking IO using iotop. This is during disk writes, for example if I open and close an empty file in gedit it can ...
6
votes
3answers
932 views

System calls supported in running Kernel

Is there a way to get the number of or list of system calls supported by currently running Linux Kernel? So I want to find a way to 'read' the syscall table of a running kernel.
3
votes
1answer
795 views

Delaying kernel upgrades on Arch Linux

On Arch Linux, whenever a kernel upgrade is applied (via pacman -Su), problems occur. For example, iptables can no longer be used: # iptables -L iptables v1.4.21: can't initialize iptables table ...
1
vote
2answers
715 views

Why should you not edit the .config kernel configuration file?

# Automatically generated file; DO NOT EDIT Is at the header of the kernel configuration file: /usr/src/linux/.config My question is why, why should you not edit this file? If I know exactly what I ...
2
votes
1answer
90 views

Tool to give only the built linux source code

Linux is large complex piece of software. A running kernel in the system would not be using all the code. I'm looking for a tool which can give me the source code needed for the .config I used to ...
0
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0answers
13 views

OpenSuse 11.1 Keyboard Issuses

Im having some repeat issues with my keyboard being unresponsive. Im using opensuse 11.1 with a 2.26.27* kernal and it seems to be getting worst. When the keyboard dies (although the mouse works) , ...
1
vote
1answer
898 views

Fedora 20 ACPI issues on black screen before log on

I installed Fedora 20 64-bit with the standard Gnome3 desktop environment and while booting a black screen is displayed with 4 messages in the following form: Failed to find handle for ACPI object ...
1
vote
1answer
190 views

How to test new kernel releases ?

I am using ubuntu 14.04 with linux kernel 3.13.0-37-generic . I know that the latest stable release of the kernel is 3.17.01 and want to test it. Can I test it on my system without blowing away my ...
8
votes
1answer
2k views

Which Debian kernel should I install?

I've started installing Debian testing on amd64 and I've come to a screen asking me to install a kernel. It gives me a choice between linux-image-3.16-2-amd64, linux-image-amd64, and none. What is ...
0
votes
3answers
118 views

Linux Distro name API to get name of linux distro in a driver code?

I am writing a common code in a driver to get the distros name and host name. host name i am taking from struct utsname{nodename[]}, but how do I get the distro name?
0
votes
1answer
371 views

Role of the Intel P state driver

I searched high and low for what “Intel P state” is and what it does. I found out that it has to do with performance and power consumption. I learned that if you build it in the kernel, it'll becomes ...
1
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0answers
495 views

How to display printk messages filtered by level as they come?

I wrote a hello word module that performs a printk when it is loaded in level ALERT and another printk when it is released with level INFO: #include <linux/module.h> #include ...
2
votes
0answers
965 views

How to create the framebuffer file node?

I'm working with a limited embedded device - Linux environment - that uses a custom DirectFB implementation to draw a user interface in its video output. I would like to exchange this method by a raw ...
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votes
0answers
53 views

Kernel version name is repeated twice

I'm compiling my own kernel on Ubuntu. I use make deb-pkg -j5 to compile and package the kernel. In the kernel Makefile, I have added "-mykernel" to the extraversion part of the version string. ...
8
votes
1answer
725 views

Why do user space apps need kernel headers?

I'm building busy-box and iptables for an embedded device and one of the dependencies for them are the kernel headers. I have searched the whole file system for *.ko files and found none. So i ...
-1
votes
1answer
84 views

Add codes to vmlinuz

When I use the vi editor to add some codes to /vmlinuz I see it in a bad format. It seems a binary file. I am going to improve security and add extra steps for checking password. How can I edit ...
2
votes
1answer
437 views

Display power management in console

When in console (i.e. not in Gnome or KDE) the display will automatically power down in case of inactivity. It seems to me to be set to something around 30 minutes. This power management is completely ...
1
vote
1answer
169 views

Is the device tree compiler tied to the kernel version?

I have a situation in which same device trees are used with different kernels. Can the device trees be build only once and used with all kernels? The reason I ask this is because I found the device ...
0
votes
0answers
1k views

Nvidia driver not working on latest kernel (3.17) and Ubuntu 14.04

I'm pretty new to kernel hacking. However, I have built my own kernel before (3.16) and it works. Now I tried upgrading to the latest kernel (3.17-rc7). I configure the kernel using the config file ...
1
vote
1answer
289 views

Binding to not existing interface

I've just noticed the very weird situation I don't have a good explanation for. The machine (debian) has one interface with one IP address assigned: # ifconfig vmbr0 |grep inet inet ...
3
votes
2answers
531 views

Easy way initrd to chain loading another kernel with kexec

I have here a machine which won't boot 64-bit kernels (it has efi32 with a little bit of... uncommon firmware). Currently, my only way to boot my 64-bit linux system is: Booting a 32-bit distro ...
3
votes
1answer
126 views

kernel: pass option to driver, when not compiled as module

I had the driver for my sound card compiled as module, i.e.: CONFIG_SND_HDA_INTEL=m and I did pass following options to the module (via /etc/modprobe.d/alsa-base.conf): options snd-hda-intel ...
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0answers
52 views

How to make 'install USB' with custom Linux?

I built my own custom kernel for new hardware.(Not a normal PC, embedded x86 device), and using syslinux I could create a booting USB for that kernel. After a few trial and errors, I was able to ...
30
votes
2answers
2k views

Why did powering down my machine after a bad `rm` save my files?

Classical situation: I ran a bad rm and realized immediately afterwards that I had removed the wrong files. (Nothing critical and I had tolerably recent backups, but still annoying.) Knowing that ...
3
votes
2answers
125 views

Linux kernel patch and development source tree

We are using linux3.12 and its led driver has a bug which got fixed in later version of Linux. We see that driver change in Linux 3.15 see Linux Cross Reference Now my question is how can I find a ...
1
vote
1answer
485 views

rts5139/rtsx_usb borked in 3.15+

Some time in 3.15, someone moved the rts5139 driver out of staging (I cannot find a changelog of this) and it got renamed to rtsx_usb. This, unfortunately, broke support for at least the RTS5139 card ...
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votes
2answers
347 views

Can anyone recommend some linux kernel related books for beginners? [closed]

I'm a newcomer of Linux kernel, and I want to know the mechanism of Linux kernel. But I was confused by such a huge number of concepts, structs and functions after the reading of Understanding the ...
0
votes
1answer
294 views

to print address space of a process in ubuntu 12.04

How do I print an address space of a process by taking the process' PID?
4
votes
1answer
439 views

kill unresponsive process

According to top, process named pccardd loads my CPU nearly 100%: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND ...
1
vote
1answer
182 views

How logical address of one process differs from the logical address of another?

I am a newbie. I am reading Understanding Linux Kernel. There, I am trying to understand how logical address got translated to physical address. To my understanding, I believe logical address got ...
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votes
2answers
89 views

Why do I have to make my own drivers?

Why does *NIX require me to make (i.e. build) my own drivers to install them? Couldn't they just be pre-built by the author and so long as they target the right CPU architecture I could install the ...
2
votes
1answer
72 views

Booting Linux minimally

I am trying to boot just linux itself. It's mostly for the learning experience. I got a small HDD with only one ext4 partition looking like this: /bin/bash /dev/console /boot/vmlinuz ...
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vote
1answer
97 views

Kernel does not load after modifying parameters and kernel image with Syslinux

# Config file for Syslinux - # /boot/syslinux/syslinux.cfg LABEL arch MENU LABEL Arch Linux LINUX ../vmlinuz-linux APPEND root=/dev/sda3 rw INITRD ../initramfs-linux-ck.img LABEL ...
6
votes
3answers
2k views

Log files for kernel panic on Arch Linux

I have recently updated my Arch Linux machine. Since then, I have been getting kernel panics here and there. (the screen freezes and the status lights on my keyboard are blinking) It seems to happen ...
6
votes
1answer
246 views

What Linux kernel features does os-prober require to find a Windows 8 installation?

I built a new custom Linux kernel using make localmodconfig and after booting the new kernel, update-grub doesn't detect my Windows 8 installation. My distro kernel (with tons of modules I don't ...
1
vote
1answer
762 views

blktrace - differentiating between sequential to random io

I'm looking for a way to determine whether an app is doing sequential or random I/O. Is it possible to look at a blktrace capture and say if I/O is sequential or random? If yes, any examples of what ...
8
votes
1answer
7k views

How interpret kworker threads names?

On Linux 3.11.0-13-generic running on top of a dual socket Xeon X5650 hexa core board, htop shows different kworker threads. Sorted by names (I tweaked the result I am showing here a little bit to ...
0
votes
1answer
185 views

How is user space process/thread controlled by the operating system

I understand this: User code executes in a process/thread context in a process address space, in user mode, and can address only user code/data defined for the process, with no access to privileged ...
1
vote
2answers
188 views

Is it bad to have too many Kernel modules?

I'm trying to compile a Linux kernel to debug an issue I have on Arch Linux, and I was configuring modules, but I didn't know what a lot of the stuff was so I left them on. If this kernel works I ...
0
votes
1answer
373 views

qemu can't run linux kernel

I saw this question and I did pretty much the same but I enabled initrd in configuration to use temporary root file system and no other modification but I still get this error on: qemu -kernel ...
1
vote
1answer
429 views

How do I compile the linux kernel version 3.16.1 to run in Slackware 14.1?

Could someone teach me or give me some tutorial? How do I compile the linux kernel version 3.16.1 to run in Slackware 14.1.
26
votes
2answers
2k views

When do I need to specify add_efi_memmap as kernel argument in UEFI/EFI boot?

I am reading some tutorials how to EFI stub (efistub) load the Linux kernel. These instructions often use kernel boot parameter add_efi_memmap. The intended hardware is Intel x64 having 8GB of RAM. My ...
4
votes
0answers
410 views

Why are block sizes limited by page size in Linux?

In many (all?) file systems that Linux uses, including ext2/3/4, the maximum block size is the page size of the architecture Linux is running on, ie. 4KiB on x86. Why is there this limit? Might this ...
2
votes
0answers
295 views

What is the minimum round robin scheduing interval supported by Linux?

For some reason, I want to have 10 processes share the same CPU core by affinity. As you know, to achieve CPU sharing between processes, we can exploit the Linux round robin (RR) scheduling policy. ...
4
votes
1answer
137 views

Is this a so-called “Hybrid” Mac Partition table, and how can I mount this in Linux?

I would like to better understand what is on this hard disk, and how I can mount it into Linux (specifically Debian GNU/Linux, Stable): It was created on a Powerbook g4 "alu book" with the default ...
0
votes
1answer
82 views

iproute command: ip -6 rule show nothing even with kernel option IPV6_MULTIPLE_TABLES=y

I want to enable my linux 3.2.4 to have ipv6 multi-routing table functionality. I enable IPV6_MULTIPLE_TABLES when make menuconfig and rebuild kernel.(Also with ip advanced routing and ip multi table) ...
0
votes
1answer
193 views

use drivers from old kernel in new kernel

I am using newest Raspbian but I found out stk1160 drivers are not working properly. But in older raspbian it works ok. So I would like to move drivers from older Raspbian to newer Raspbian. How can I ...
3
votes
1answer
1k views

How to debug random reboots, with no kernel panic, of an embedded system?

I have two aValue RPC-10W1 embedded systems that reboots by themselves after 1-2 hours. Facts: The board will reboot within a time span of 1 to 2½ hours. The issue is present on two identical ...
0
votes
1answer
105 views

How to take the log of the patches we applied?

So here's my question I recently downloaded the linux kernel patch 3.4.101 and i applied this patch directly to the base 3.4.0 with this command: $ cd /kernel source directory $ gzip -cd ../path to ...
2
votes
0answers
84 views

Possibile sources of 5us-20us latency gap when sending long block of of serial data to tty device?

I have a trivial C program that just sends a large block of data out the serial port at a fast baud rate. When looking at the bits actually coming out of the port, I see that there is a almost always ...