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

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U-Boot Bootup error

I'm running a Debian Linux on a Cubietruck, running off a SD card. When I power on, I get the following error: Booting kernel from Legacy Image at 46000000 ... ...
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2answers
203 views

Generate major page faults

Is it possible to generate major page faults in the linux kernel at will? Can a program be written such that it is guaranteed to cause a major page fault on it's execution.
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41 views

Linux Networking Bootup script takes too long

I am working with a fork of a raspberry pi SoC. One of the modification is the use of AP6210 WiFi/Bluetooth chip. I am running Debian. During boot up, the following 3 startup scripts need to run in ...
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1answer
90 views

How does the Linux kernel initialize console graphics?

Observation: I switch on a Linux box Boot loader displays its output on screen Boot starts with first output messages Screen goes blank, and never comes back on. Note: this is about the console, ...
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1answer
86 views

Recognizing GPT partition table created with different logical sector size

I have a 3TB drive which I have partitioned using GPT: $ sudo sgdisk -p /dev/sdg Disk /dev/sdg: 5860533168 sectors, 2.7 TiB Logical sector size: 512 bytes Disk identifier (GUID): ...
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1answer
60 views

NAS: 100% system (kernel) cpu usage

I have a single core NAS My Live Duo. It runs Debian lenny release. I found via htop utility that it constantly use 100% of red cpu without any noticeable process to eat it. Than I checked via iostat ...
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31 views

Linux Kernel Version >=3.14 Obliterates Wi-Fi Dongle!

I own a TP-LINK WN725N, and any linux distro with the kernel version before 3.14 works fine, but past 3.14, the dongle cannot hold a speed of over 10 kb/s for more than 10 seconds. Reconnecting solves ...
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54 views

Do dracut handles boot parameters mentioned in dracut.cmdline (7)

If I understand correctly, in boot time the kernel will mount initramfs and then calls /sbin/init from it(which is a symbolic link to /lib/systemd/systemd on Fedora/RHEL systems) and dracut itself ...
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202 views

Debian wheezy, 3.19, problem keyboard and mouse on dekstop environment

I am running Debian Wheezy on a BananaPi. I just compiled the kernel and the keyboard was working in terminal(if it's called that way). However, after I installed a dekstop interface using "apt-get ...
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2answers
211 views

Log message “Disabling IRQ”: what does it mean?

This message appears in my dropdown terminal at seemingly random times when no processes is running in that terminal: andreas@debianator:~$ Message from syslogd@debianator at Feb 24 18:57:58 ... ...
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73 views

Print list of bad blocks in NAND flash from user space

Is there any user space tool that can retrieve and dump the list of bad blocks in a NAND flash device? I've checked the mtdinfo command line utility, and also searched /proc and /sys, but couldn't ...
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4answers
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Why some operating systems event handling is written in asm instead of c?

My question is why nowadays some operating system event handling is still written in assembly language instead of a higher level language such as C, when the kernel itself is written mostly in C?
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225 views

Centos 7 boot up with custom kernel problem

I have installed centos 7 on virtualbox machine which has kernel-3.10.0-123.20.1.el7.x86_64. I am trying to build Linux kernel from kernel sources. I downloaded the kernel source files from: ...
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25 views

insert module to kernel

I installed latest version of IPCOP, I've the correct module of my wireless card (htc_9271.fw): put it to /lib/firmware/ there is not any insmod/rmmod but only modprobe: modprobe htc_9271 FATAL: ...
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1answer
185 views

RTC time synchronization not working (CONFIG_RTC_SYSTOHC)

I have the option CONFIG_RTC_SYSTOHC enabled in my kernel: Device Drivers ---> [*] Real Time Clock ---> [*] Set the RTC time based on NTP synchronization The help says: ...
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1answer
112 views

Few questions about system calls and kernel modules (kernel services in parallel)

I have few questions about system calls and kernel modules. Let's assume we have two applications (A and B) and each of them is running on a different core. (A-CPU 0, B-CPU 1) When two applications ...
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1answer
138 views

setting (system-wide) CPU affinities for running processes on a Linux platform

I am conducting a kind of research in that I schedule multiple parallel applications (e.g., OpenMP/pthreaded applications) and execute the applications on specific (partitioned) cores on Linux-based ...
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1answer
158 views

Enabling ethernet over usb support in Linux Kernel

How to enable Ethernet over USB support in linux kernel. Which driver(like CONFIG_USB_USBNET) is related to this support. Is EEM (Ethernet Emulation) regarding this support or not..???
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23 views

Slow graphics when using kernel without module unloading support

If this is the wrong place for this question, please let me know. I didn't know where to ask, so here we go: Initially I wanted to disable module loading support for my linux kernel because I know ...
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0answers
137 views

Is it safe to disable Frequency Scaling and CPU idle Power Management support for Real Time purposes?

I'm using a Raspberry Pi board and I would like to build a real time system. During the kernel configuration, I found the CONFIG_CPU_FREQ option, which (from the help section) allows you to change ...
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1answer
365 views

Compiling kernel but doesn't build kernel modules

I am trying to compile a linux-sunxi kernel for my Banana pi. Using this link: http://sunxi.org/Linux_Kernel#Compilation Unfortunately I am getting the following message at the bottom when I am ...
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354 views

update kernel without restart

Recently Linux got a new feature called Live Kernel Patching, which you means you dont have to restart your system to update kernel. Is there any other kernel which has this feature already or Linux ...
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51 views

Boot partition was unmounted during kernel update

So, I updated the kernel from 3.18.5-Arch to 3.18.6 and without mounting my boot partition. Now, no usb device (vfat not recognized) can be mounted and no network connection (no interface except lo) ...
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525 views

dmesg: pci BAR 7: can't assign io

I have VMware virtual machine running Debian Wheezy. I have compiled my own kernel 3.14. I have noticed dmesg is flooded with messages pci BAR 7: can't assign io (size 0x1000). I have no idea what ...
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24 views

How to instruct RHEL6.5 Linux to save/starts states before crush or restart

I have multiple Workspaces, each responsible for different revisions of the same software. Not to have to recreate all Worspaces and open all tools/windows, I'm wondering how can I instruct Linux to ...
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2answers
46 views

Kernel panic if LUKS password is bad x times

Q: Is it normal if a RHEL 6.5 machine kernel panics if I type the LUKS password a few times wrong?
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196 views

lsof: measure I/O rate of a socket fd

I'm writing a script that parses the output of lsof to show a list of what processes have sockets open (similar to what netstat shows). lsof also gives me a file descriptor. What I want to do now is ...
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63 views

USB keyboard is disconecting automatically (without being unplugged)

In my log, I see following message: kernel: usb 1-1.6: USB disconnect, device number 5 acpid: input device has been disconnected, fd 7 acpid: input device has been disconnected, fd 8 I have not ...
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107 views

cannot locate header while making buildworld in custom kernel source

I'm trying to install a custom kernel in freebsd and here's step I followed: install freebsd 9.1 on vm from the image get the source from hardenedBSD (branch hardened/9/kernsep) execute "make ...
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80 views

Why doesn't Linux IPSec implementation support fragmentation before encryption?

I am trying to address an issue where ESP packets are getting fragmented as after adding the ESP header the MTU size is exceeded. The solution—which is what everybody does—is to do the fragmentation ...
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1answer
161 views

Kernel ATA Exception after resume from suspend to RAM

After resuming from suspend to RAM, my Arch Linux system freezes and becomes permanently unresponsive. However, I managed to pull the following kernel log: kernel: sas: Enter sas_scsi_recover_host ...
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2answers
1k views

How to disable core dump generation in Centos (cPanel Server)?

I want to disable core dump generation, How can I disable it ? One of the website keeps generating core dumps every second and eats up all the disk space. OS Details: CentOs cPanel Server ...
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1answer
107 views

What is “fs” short for in kernel function “get_fs()”?

There are two Linux kernel functions: get_ds() and get_fs() According to this article, I know ds is short for data segment. However, I cannot guess what "fs" is short for. Any explanations?
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Kernel compilation for minimum program execution

Compiling the Kernel requires me to configure modules. I am unsure how to configure a Kernel which only supports following things: Programs compiled with gcc on other machines (glibc). I want to run ...
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Installing kernel headers (prior to `make install_headers`)

I'm trying to accomplish this make ARCH=x86_64 INSTALL_HDR_PATH=/opt/cross/x86_64-linux headers_install But with the 2.6.9 kernel tarball. It does not support the make target headers_install and ...
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1answer
61 views

How to see kernel time variables without using adjtimex?

The man page for adjtimex says Anyone may print out the time variables, but only the superuser may change them. How do I see the value shown by adjtimex -p as the tick variable without using ...
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238 views

Debian boot freeze (hard lockup)

I'm using debian sid and during two years i watch the same problem. When I boot from grub my system on the screen appears follow text: Linux kernel in decompress level...Parsing elf and then freeze ...
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1answer
26 views

How do kernel inform OSPF daemon when a physical interface status is down?

When a physical interface status is changed from up to down, there are 3 things related to the computer's current routing table and OSPF. The (connected) network for that interface and remote ...
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1answer
20 views

Kernel config: Is undefined the same as disabled?

Reading the Debian Kernel Handbook I came across the config option CONFIG_DEBUG_INFO. That option isn't in the official debian 3.2 kernel config, so what I'd like to know: If a certain option is not ...
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39 views

Improve kernel boot time

I am using OMAPL138 and kernel version 2.6.37 and I would like to improve the boot time. By analyzing the kernel boot process I think it is taking a long time at MII PHY CONFIGURATION. The printscreen ...
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42 views

Debugging info in linux kernel - how does it work?

I have found that I can compile linux kernel with some flags adding debugging support like CONFIG_DEBUG_INFO. These options while useful in debugging are also required by some utilities like ...
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2answers
169 views

Why is Linux “Unix-like” if its kernel is monolithic?

As I understand it, part of the Unix identity is that it has a microkernel delegating work to highly modular file processes. So why is Linux still considered "Unix-Like" if it strays from this ...
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2answers
107 views

How to return 0 if a pattern is matched from a file? [duplicate]

I have a binary that repacks android kernel (not mkbootimg). I'm making a script to automate the process. I don't want any output on the screen. So I have redirected the output to a file named ...
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3answers
97 views

Boot process - Dev sdX name changes

I had a Slack 13.1 machine with 2.6.36 kernel. Then, I updated the kernel to 3.12.1. This machine has connected: a bootable disk with three partions (/dev/sda1 --> Linux OS files..., /dev/sda2 --> ...
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0answers
1k views

Install rtl8188etv/rtl8188eu driver on Orange-Pi

I'm trying to install the wifi driver on Orange-Pi board. The real chip is rtl8188etv but the driver is the same. I have compiled 3.4.105+ Kernel to have the headers: mkdir ...
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0answers
70 views

View syscalls/kernel activity for I/O from a running process

I'd like to be able to view syscalls or kernel activity for a process...I'm not actually sure of the terminology I need here! Specifically I'm looking for the difference between I/O going to local ...
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1answer
49 views

What is /proc/filesystems supposed to be and why is it different from /lib/modules/linux_ver/kernel/fs?

The very little documentation about /proc/filesystems says it is a "list of supported file systems". I see a lot of file system modules in /lib/modules/linux_ver/kernel/fs, most of which do not appear ...
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1answer
124 views

Missing kernel headers, but need them to install the Wifi driver

I am trying to install Kali on my Lenovo Yoga13, but after formatting the disk the setup failed to install grub because of no internet access (no Ethernet, need driver to get Wifi to work). So, I ...
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2answers
310 views

ubuntu Kernel panic while installing CentOS 7 in VirtualBox

I have a laptop with Xubuntu desktop 14.10 , and I installed VirtualBox and updated it to the latest version . I'm trying to install CentOS 7 (source downloaded from the official site) as a VM, ...
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1answer
151 views

Cannot update new kernel for CentOS 7 although the server have space enough

I try to update kernel on my CentOS 7 but the yum say there is no space enough on /boot although /boot have 343 MB as show below: Filesystem Size Used Avail Use% Mounted on /dev/sda2 477M 105M 343M ...