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

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1answer
62 views

What does kernel-wedge do?

After looking at the package description and using kernel-wedge help, I'm not really sure what it does. Does it take a .deb kernel package and split it into smaller packages? Does it compile a ...
0
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0answers
40 views

How to recompile official OpenSUSE kernel & initrd?

But it is not okay. I want all of the suse patches applied, I want an official initrd to be generated, and I want to make rpms from all of them. So, I want to recompile the kernel just as the SuSE ...
0
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1answer
117 views

Mount JFFS2 FS in openwrt

I'm trying to mount 1[MB] of flash as JFFS2 FS in openwrt environment, using 128[MB] NAND flash (4 bit ECC). I'm using the following sequence - flash_eraseall -j dev/mtd6 mount -t jffs2 -o noatime ...
2
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0answers
106 views

Explanation of the building process of the kernel on Ubuntu/Debian systems

I'm getting into Linux kernel programming and I have successfully built my own kernel several times now. However, I have done it using step by step guides found from the internet and I don't really ...
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0answers
76 views

Fedora 20 won't startup after shutdown during kernel update

I had a few bugs in my System(System Settings not opening and Firefox not starting) and I thought a kernel update(via yum) could do it some good. During that update, I suddenly got logged out as if ...
5
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1answer
140 views

Linux kernel dropping custom keyboard scan codes

I have a vintage IBM 122 key model M keyboard that I am adapting for use on a modern computer. I am using a Teensy 2.0 to do the encoding and to handle the USB side of things. I borrowed the firmware ...
13
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1answer
3k 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 ...
0
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2answers
75 views

Compilation error when building a custom kernel

I'm trying to build a custom kernel from a git repository on my Ubuntu virtual machine. I run the make command as follows : sudo apt-get install vim libncurses5-dev gcc make git exuberant-ctags mkdir ...
0
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1answer
614 views

modpost.h:12:23: fatal error: elfconfig.h: No such file or directory

I am running Ubuntu: #lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04.4 LTS Release: 12.04 Codename: precise Kernel info: 3.8.0-38-generic ...
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2answers
2k views

CentOS ELRepo Kernel installing VMware

Already installed VMware Workstation 9 on my Linux CentOS 6.5 Final with 3.10.40-1.el6.elrepo.x86_64 running kernel. When I open VMware Workstation, it asks me to locate the Kernel Headers ...
26
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4answers
2k views

What are the responsibilities of each Pseudo-Terminal (PTY) component (software, master side, slave side)?

I am trying to figure out how a tty works1 (the work-flow and responsibilities of each elements). I have read several interesting articles about it, but there are still some blurry areas. This is ...
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1answer
55 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 ...
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6answers
6k views

Compiling GNU/Linux with -O3 optimization

It's said that compiling GNU tools and Linux kernel with -O3 gcc optimization option will produce weird and funky bugs. Is it true? Has anyone tried it or is it just a hoax?
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0answers
86 views

Linux Oracle - Random crash CPU Stuck

I have several Linux oracle VMs running under hyper-V. Kernel version is 2.6.32-358.el6.x86_64. Sometimes, the VM stuck, we still can ping it, but we cannot ssh, or through the hyper-v console this ...
1
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0answers
39 views

How build wireless-compat-old in-kernel?

I'm running linux 2.6.24 with custom patches from Freescale, on an embedded board. I want to use a usb wlan modem that uses the Realtek rtl8191su chipset. Realtek provides a driver out of tree, ...
0
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1answer
212 views

ZFS support for linux kernel versions 3.16

Attempting to boot Funtoo with a debian-sources-3.16.2-3 kernel, in a system where the root file-system lives in a zpool, drops off to the rescue shell after failing to import the pool properly. Does ...
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0answers
33 views

extract Embedded initramfs

I have a kernel in which one initramfs is embedded. I want to extract it. I got the output x86 boot sector when I do file bzImage I have System.map file for this kernel image. Is there any way to ...
2
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1answer
44 views

How to find the source of a currently running kernel on my machine?

I have a Linux 3.14.0 kernel(CentOS 6.2) running on my machine, but the source isn't in /usr/src/. Is there any way to find out the source from which it was compiled? The source is most definitely ...
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2answers
85 views

Linux 3.x init ramdisk embedded in bzImage?

Is the initial ramdisk embedded into the bzImage? How to load an rootfs.cpio as a ramdisk and switch the root?
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0answers
77 views

Do kernel threads seem to interfere with full tickless mode?

I'm trying to disable local timer interrupts for low latency. I have full tickless mode enabled in the kernel config and I have the boot parameter nohz_full set for the cores in question. However ...
1
vote
1answer
445 views

Kali Linux - “package has no installation candidate” (also thinkpad-acpi)

I was trying to install the thinkpad-acpi package unsuccesfully, since it had not found the directories needed at all. (no such file or directory response after running the cat ...
0
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1answer
289 views

Debian stable: Only GNOME classic with custom 3.16

I compiled a custom 3.16.2 today, which works flawlessly except that GNOME only starts in classic mode. Maybe this is due to changes in the drm i915 driver, but how would I debug this? System is a ...
0
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0answers
275 views

yum install kernel-devel: “Nothing to do” [SOLVED]

I need the kernel-devel package to compile a program(How to check if USB WiFi-Adapter is not working or router is out of range?), but when I try to install it via yum, this is the only output: yum ...
0
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1answer
86 views

How to recover firmware on a embedded device with corrupted u-boot and kernel image? [closed]

My embedded device is not working after updating firmware. Thus I tried to update firmware using u-boot. I could successfully get u-boot console via serial connection, but updating firmware failed due ...
0
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1answer
63 views

auditctl reports “File system watches not supported” on a very old system

When I run auditctl -l I got: # auditctl -l No rules File system watches not supported And I've already have AUDITSYSCALL enable in kernel, # zgrep AUDIT /proc/config.gz CONFIG_AUDIT_ARCH=y ...
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0answers
22 views

third party linux auditing software

Linux has a audit system built-in in its kernel and a user space process called auditd reading the system calls intercepted by the kernel. Are there alternate solutions to the Linux Audit system ? I ...
2
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1answer
159 views

How to check and set “rhash_entries” parameter?

I'm reading this article, and it says: rhash_entries is the size of the hash table. If you don't specify it on the kernel command line, it is computed dynamically based on the memory available on ...
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0answers
130 views

Linux 0.0.1 Kernel - Starting Kernel Programming

To start kernel programming, instead of reading the books, the online references suggested to download the linux 0.0.1 source and find bugs. I have downloaded it and I am going through the code with ...
3
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1answer
30 views

Real-time executive approach, can be run in desktop Linux?

With the real-time executive approach, a small real-time kernel coexists with the Linux kernel. This real-time core uses a simple real-time executive that runs the non-real-time Linux kernel as its ...
2
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1answer
413 views

Real time processes scheduling in Linux

I have been learning some scheduling concepts. Currently my understanding so far is as below. There are real time processes and non real time processes. Non real time processes can have nice values ...
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0answers
24 views

Patching and Compiling my Kernel

So I have an issue with my USB 2.0 ports and I believe I have found a solution for it, which is in the below link. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1210858/comments/32 I have ...
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0answers
241 views

Some questions compiling linux kernel with make-kpkg

I'm doing my first steps compiling the linux kernel and adding a new system call. I've managed to do it, but I still have some questions. For this task, I has set up a Virtual Machine guesting debian ...
2
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1answer
76 views

strace works for some builtin commands

I'm trying to understand some kernel level concepts in Linux. I was checking on the difference between shell builtin commands and the other executable commands. This wonderful answer clearly tells ...
1
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1answer
340 views

ixgbe: increase rx performance

I have an Intel 82598EB 10GBE NIC. I need to receive traffic without packet loss. Data rate is 4-5 Gbps, packet size is 1500-9600 bytes. I had already configured smb and irq affinity. I also tried ...
5
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3answers
8k views

Cleaning log files under linux

I am using a kvm ubuntu 10.04 virtual machine to test some features of a kernel module. I grep through the /var/log files to observe the kernel messages about that module. To start from a clean ...
1
vote
1answer
33 views

rebuilding kernel without using apt-get

I am setting up my Macbook Air 6.2 with Debian Jessie. since I do not have any wireless, I need to set it up manually, but all documentation I find how to do it are using apt-get apt-get install ...
0
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0answers
120 views

USB Keyboard Hotplug Module not Working

The following module could be compiled and loaded without any error: #include <linux/module.h> #include <linux/kernel.h> #include <linux/usb.h> #include <linux/usb/input.h> ...
4
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3answers
560 views

Compare two kernel config files from the menuconfig perspective?

I have a situation in which i have two kernel config files (for the same kernel source ). Both of them have a part of the functionality that i need (on one, USB works correctly, on other, the second ...
9
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5answers
5k views

Given a kernel ATA exception, how to determine which physical disk is affected?

I woke up this morning to a notification email with some rather disturbing system log entries. Dec 2 04:27:01 yeono kernel: [459438.816058] ata2.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x6 ...
2
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1answer
127 views

What does the CONFIG_NLS_UTF8 kernel option do?

The kernel configuration contains an NLS_UTF8 option. It can be found under File systems → Native language support. What does it do? Its description maintains that it is needed for using a FAT or ...
3
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1answer
3k views

After installing a new Kernel in Ubuntu 14.04, rebooting takes me to busybox initramfs. How do I mount a filesystem after that?

I have a virtual machine with Ubuntu 14.04 in it. I recently built and installed linux-3.14.5 kernel on it, and tried to boot into it, but it drops me to BusyBox v1.21.1 built-in shell. Here's what I ...
4
votes
3answers
9k views

mount.cifs : mount error(12) : Cannot allocate memory

I encountered this problem a while ago when upgrading my kernel but put off upgrading until now. On my system I can happily mount network shares using CIFS running kernel 3.7.10, however when I've ...
1
vote
1answer
2k views

How to fix unreliable Realtek Wireless card on Ubuntu 13.04

I have a Realtek RTL8188CE wireless card and it works fine when I have a strong signal, but if I get even slightly away from the wifi I lose connectivity even though there is a strong Rx signal. I ...
2
votes
0answers
37 views

Why does each process folder under /proc contain the same information?

Under /proc/<PID>/net pseudo-file system each process seems to have files with the same content. For example I use cat /proc/<PID>/net/ip_tables_names to list iptables tables under the ...
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0answers
32 views

how to limit dma address to specific range in linux kernel?

I want to limit the dma address the device can access to 0x0100_0000~0x03ff_ffff. But I don't know how to set the dma_mask and coherent_dma_mask. It's easy to set the "dma mask" for a range start ...
2
votes
1answer
744 views

How does bash execute an ELF file?

When I'm on my Linux Box I use bash as a shell. Now I wondered how bash handles the execution of an ELF file, that is when I type ./program and program is an ELF file. I grepped the bash-4.3.tar.gz, ...
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0answers
75 views

Noob Kernel Image Question

I'm playing about with CM-FX6 , an iMX6 based SOC. The chip comes with the following: http://www.compulab.co.il/workspace/mediawiki/index.php5/CM-FX6:_Linux:_Kernel **images** uImage-cm-fx6 - ready ...
2
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0answers
37 views

Why is there no rootfs file system present on my system?

The linux kernel documentation claims: Rootfs is a special instance of ramfs (or tmpfs, if that's enabled), which is always present in 2.6 systems. You can't unmount rootfs … On all linux ...
1
vote
1answer
51 views

Booting into a kernel image

I have a recently-compiled Linux kernel image (vmlinuz file) and I want to boot into it. I am aware that this won't give me a familiar Linux system, but I am hoping to be able to at least run some ...
2
votes
2answers
1k views

Linux freezing guess: keyboard & mouse (Archlinux and Ubuntu)

Linux on my PC is freezing a few seconds after startup. I am unable to use the mouse / keyboard. Neither Ubuntu nor Arch do anything after a few seconds. Windows has been running fine for years now. ...