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

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psmouse sync issues!

I have Compaq CQ61-420US (64-bit AMD) laptop with Synaptics touchpad checked using $ egrep -i 'synap' /proc/bus/input/devices N: Name="SynPS/2 Synaptics TouchPad" But recently after Arch Linux ...
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1answer
51 views

Is there a man section or other doc repository for data structure definitions?

For the millionth time or so I had to look in /usr/include/foo.h to find the members of a struct foo or foo_t or whatever. There's a man section for library and kernel calls, some of which include ...
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30 views

SLES 10 SP4 - how to get specific kernel source?

I want to look at the kernel source for some specific kernel versions on SLES 10 SP4. I don't want to see just the Linux kernel source, but the one SLES is actually running. Suppose I wanted to get ...
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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 ...
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1answer
69 views

ncurses-devel problems in SuSE Linux Enterprise Desktop 11

Searching on the WEB, I found this tutorial (the only one that has convinced me) for installing a new kernel and I followed the steps provided. But, I got these problems: In the first step I tried ...
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Calling speaker-test from usermode-helper API

I needed to call come audio-producing applications from kernel in a toy module. In order to test that, I thought of calling speaker-test from a simpler module, but no sound would ever come from it. I ...
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3answers
55 views

Un-mount active partition

Is it possible to umount the partition, whose files/directories are in use? The underlying files and directories are in memory so un-mounting the partition is technically safe (I guess). But umount ...
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58 views

cross compile embedded arm

I have the android 4.2.2 code in directory /home/sghPhone2 which compiles normal with make menuconfig but I need to compile a 4.4 kernel and possibly patch it but when I download the source from ...
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63 views

Could it cause any problem if I not reboot after a kernel upgrade?

I know there are solution for not rebooting after kernel update: https://en.wikipedia.org/wiki/Ksplice But If Ksplice isn't installed, and the user doesn't reboots it's notebook after even several ...
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421 views

YUM won't update KERNEL

... ... ... --> Running transaction check ---> Package db4-devel.x86_64 0:4.7.25-18.el6_4 will be installed --> Processing Dependency: db4-cxx = 4.7.25-18.el6_4 for package: ...
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401 views

get kernel source code

I need a specific kernel version to compile it with some additional modules. When I typing: uname -r I get 3.8.0-29-generic I need this one. uname -a Linux "..." 3.8.0-29-generic ...
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79 views

How not to write kernel warnings into /var/log/messages?

I keep getting these log warnings due to a bug in kvm. Jun 30 19:12:31 server kernel: kvm: 28882: cpu0 ignored rdmsr: 0x345 Jun 30 21:12:31 server kernel: kvm: 31191: cpu0 ignored rdmsr: 0x345 Jun ...
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30 views

How to modify huge patch file properly?

I have this patch. I want to disable patching of Makefile and drivers/video/logo/logo_linux. What is best way of doing this? Do I edit it, and delete that specific entries? If so, is there a tool ...
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1answer
532 views

Upgrading kernel 2.6.18 to 2.6.32 on CentOS 5.10

I've been looking on Google for 4 hours and I can't find a solution to my problem. I have a computer running CentOS 5.10 using Kernel 2.6.18-371.9.1.el5 and I would like to upgrade my kernel to ...
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43 views

The meaning of Linux Kernel bug output

I have a quick, (maybe naive),question about Linux kernel's output. When I issue a command, the system (Ubuntu 12.04) freezes, the serial port output of this system is as follows: [ 373.805067] BUG: ...
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188 views

Debian + Linux kernel 3.12.22: “Kernel module loader” option is not available

The Debian guide for compiling a kernel says: Do not forget to select “Kernel module loader” in “Loadable module support” (it is not selected by default). If not included, your Debian installation ...
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47 views

Common code for kernel and userspace [closed]

I'm working on a linux project. I want to have some code (to be specific, a struct) and a header file (my own implementation) common to both the kernel and the userspace. Can someone tell me how to ...
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60 views

Debian: GPG cannot fetch Linux Kernel key

I am in the process of recompiling the kernel on Debian. Following the instructions on kernel.org, the first step is to verify the signature. But GPG complains that it cannot find the public key: # ...
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44 views

Automatized kernel upgrade

I am writing a BASH script that automatically configures, builds and installs the most recent kernel image. The generated kernel should include the grsecurity patchset. It would use the previous ...
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79 views

kernel build: why does 'make install' complain about missing modules?

I'm building a 3.2.x kernel on a RedHat Enterpise system. During 'make install' it takes a very long time and is complaining : ERROR: modinfo: could not find module xxx I assume its probing ...
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1answer
61 views

Open Character Device without creating a Device Node

I'm having an issue where a 3rd party application is opening a device node it shouldn't. I wrote a SPI Slave device driver that does some processing of messages. When the driver loads its in ...
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What does this “general protection fault” in my console mean, and how do I interpret it?

I had a couple of consoles open for other work and when I came back to them they both contained the following: Message from syslogd@Stacey-Windows at Jun 19 09:43:28 ... kernel:[ 4375.127165] ...
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What's the difference of the Userland vs the Kernel?

I am trying to understand exactly what is userland? everyone that I ask says: "Anything that is not kernel". but it is not tangible for me. When I am reading that kernel can run that driver on the ...
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2answers
68 views

Debian: get package name for installed file

I'm connected via SSH to a PC running Linux kernel 3.11.1: root@alix:~# uname -r 3.11.1 how can I find out which package installed this specific file or kernel version respectively? I tried ...
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687 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. ...
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1k views

Where does uname get its information from?

Where does uname really get its information from? I figure this is something that should be straightforward. Unfortunately, I can't find any header containing just that information. Say someone ...
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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 ...
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1answer
64 views

Find out if CPU supports dynamic speed setting

I need to find out in my script if a (potentially legacy) CPU supports dynamic speed setting, and eventually get value of maximum and current speed. What makes it more complicated is that I need to ...
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1answer
281 views

Realtek RTS5209 PCI-E Card Reader only work if card is inserted before boot

Hardware Info Laptop Model: Sony Vaio Pro 13 Problematic Hardware: Bulti-in Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader Problem description Here is the problem, if I boot with ...
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1k 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 ...
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Updating kernel on a Chromebook to prep for Chrubuntu

Pretty simple question: I have read that by setting my Chromebook to the dev channel, it will install a later kernel. Currently it's 3.4.0, and it'd install 3.8.0 (64-bit, no less). However, after ...
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227 views

Kernel 3.14.1 compilation errors

I installed the kernel 3.14.1 and there seem to be no issues. uname -r 3.14.1-031401-generic However, when I try to go to the folder and try to do a make it fails. I see that multiple files are ...
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91 views

When is swap triggered or how to calculate swap_tendency?

I'm trying to use Redis for production services and trying to avoiding swapping, which is bad for performance. I had learn that swap is triggered by swap_tendency which is depending on ...
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1answer
57 views

kernel event listener

I wonder if there is something similar to an event listener in UNIX that a program can subscribe to? Specifically I want to know: Start and end times of a user session Start and end of the ...
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67 views

What causes /proc/<pid>/* resources to become owned by root, despite the procs being launched as a normal user?

I've noticed that some procs, such as bash, have their entire /proc/<pid>/ resources readable by the user who created that proc. However other procs, such as chrome or gnome-keyring-daemon, have ...
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Adding IPVS to the kernel

I am trying to setup keepalived on a pair of VPS load balancer servers. I have hit the road block of IPVS not being included with the kernal. IPVS: Can't initialize ipvs: Protocol not available I ...
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Intel Xeon stuck at 800mhz CPU Freq on RHEL 6.5 [duplicate]

Currently running into a headache trying to figure out why my CPU speed is stuck as such a low frequency. After doing some research, I found that cpuspeedutil does actually control the state of the ...
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2answers
64 views

How to find out the bad block table offset and how to change it in u-Boot

I am facing a similar problem as this: Kernel does not recognize nand bad blocks marked by u-boot I'm using a friendlyARM micro2440 board that contains the s3c2440 ARM processor. u-Boot has found ...
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117 views

Porting jvm into the kernel space?

Currently I am playing with the idea of a jvm running in the kernel space, as a (maybe linux) kernel module. I see a lot of advantage of the idea. Of course the biggest advantage of a such system ...
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35 views

Get log from kernel while loading

There is a arm/omap2-based device without ethernet, UART ports. It has usb connection with host, numeric keyaboard, LCD display. There is working U-Boot and kernel images for this. I'm trying to ...
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164 views

Library routines in linux kernel

In the linux kernel, there is a section "Library routines" with a snippet shown below: Library routines ---> <M> CRC-CCITT functions <M> CRC ITU-T V.41 functions <M> CRC7 ...
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1answer
75 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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ftdi_sio not pre-installed

I have recently recompiled my Ubuntu's kernel to Linus' most recent one. After rebooting, I tried to connect my computer to a development board via an FTDI FT232 USB-to-Serial converter. It used to ...
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61 views

How to set sctp_nodelay to enable piggybacking while replying back

Problem: We are hosting a telecom application that receives traffic from the network at > 500 TPS. The packets are piggybacked so each sctp packet contains multiple application layer packets lets say ...
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140 views

custom kernel and firmware loading

After I have compiled my kernel, and when I type make modules_install, not only are the modules copied into /lib/modules/ but also firmware is copied into /lib/firmware/. The following is the end of ...
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664 views

Where does make defconfig get its configuration in OpenWrt?

I am compiling an image for wifi devices using OpenWrt. Following the instruction I copy a simple .config file to TOP-DIR. CONFIG_TARGET_ar71xx=y CONFIG_TARGET_ar71xx_generic=y ...
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Black screen when kernel boots with vga= parameter

Recently recompiled kernel refuses to do output on the screen if vga parameter was in the list. Without it kernel boots properly as usual, however, before that it changed resolution and RC log ...
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166 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 ...
2
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1answer
64 views

What is the difference between all and default in kernel setting? [duplicate]

I want to enable reversed path filtering to prevent source ip spoofing on my server. I noticed that I have the following settings at current: net.ipv4.conf.all.rp_filter = 0 ...
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85 views

MIC not working due to USB bandwidth

Using debian and centos, i get the same error when plugging my USB mic in. In Windows (xp thru 8.1) it works fine. [ 304.237543] usb 2-1.6.2: USB disconnect, device number 6 [ 305.220785] usb ...