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

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4
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2answers
937 views

Benefiting of sched_autogroup_enabled on the desktop

I am running a 2.6.37 kernel with sched_autogroup_enabled set to 1. I am not certain that I am seeing the benefits of this patch since: I am launching my applications from the desktop; applications ...
0
votes
2answers
20 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 ...
34
votes
7answers
23k views

Linux Kernel: Good beginners' tutorial [closed]

I'm interested in modifying the kernel internals, applying patches, handling device drivers and modules, for my own personal fun. Is there a comprehensive resource for kernel hacking, intended for ...
17
votes
3answers
9k views

What is the difference between the following kernel Makefile terms: vmlinux, vmlinuz, vmlinux.bin, zimage & bzimage?

While browsing through the Kernel Makefiles, i found these terms. So i would like to know what is the difference between vmlinux, vmlinuz, vmlinux.bin, zimage & bzimage?
1
vote
1answer
33 views

What causes the ata exceptions in my syslog and how to solve them

I have a new system with debian (omv) a SSD hard drive for the OS and a software RAID 6 for the data. I only saw now that I have very regular exceptions in my syslog. I'm worried now, what could ...
0
votes
1answer
6 views

CONFIG_NF_CONNTRACK is not set

I am trying to setup iptables on udoo quad but I hit a brick wall and cannot find a fix anywhere: root@udoo:/# uname -a Linux udoo 3.0.35 #10 SMP PREEMPT Wed Jul 30 18:16:10 CEST 2014 armv7l ...
2
votes
2answers
1k views

busybox initramfs loop mount

I'm trying to loop mount my root filesystem (a loop file) within a busybox initramfs. I try to run the command: mount /rootfs.raw /root ... which works on my Ubuntu laptop, however, I simply get ...
0
votes
1answer
98 views

To run modprobe for Wi-Fi at login

I would like to enable my wifi card automatically at the startup every time. However, the command below requires sudo. I see Hardware Disabled at the wireless connection which blocks the internet ...
23
votes
3answers
1k views
1
vote
2answers
25 views

How to get the name of USB driver in use in linux

I'm running Ubuntu 14.04 on my laptop. I'm having USB related issues in my laptop. It works sometimes and sometimes doesn't. I thought of fixing the issue myself. So, I wanted to know if there is a ...
0
votes
0answers
25 views

grub2: error: /vmlinuz-3.16-ucs109-amd64.efi.signed has invalid signature

I am using a derivative of Debian, called Univention Corporate Server. It's a nice appliance that I use for my home server. Yesterday I upgraded to the newest version and since then my server does not ...
2
votes
1answer
3k views

modules make: *** /lib/modules/3.7-trunk-amd64/build: No such file or directory

I need to install Kali Linux updates without Internet access on my laptop. I think I need to do this because I'm trying to install the WiFi driver but I get an error when I try to make: make ...
0
votes
1answer
32 views

Option to configure Linux kernel to run userspace script when core dump occurs?

Is there any option in the kernel compilation or userspace setting to do the above? I'm looking to add a crash reported to my new embedded Linux system.
0
votes
1answer
11 views

SLES official repository connection (activation code available for SLES 12, not SLES 11 SP3) solution: use SLES SP4

How could I connected to official repository from my SLES 11 SP3? I need to update my kernel etc. Here my previos active-search post =) How to get 60 day SLES activation code
2
votes
0answers
10 views

What could cause dropping cache to be extremely slow on a large cluster?

I'm attempting to time file I/O on my disks. In order to make sure all the I/O is happening off the hard drives and not from ram, before I time any read, I run a drop cache command. Specifically, I ...
26
votes
6answers
37k views

disable transparent hugepages

We are installing SAP HANA in a RAID machine. As part of the installation step, it is mentioned that, To disable the usage of transparent hugepages set the kernel settings at runtime with echo ...
4
votes
1answer
2k views

Setting up HDMI output from Linux console

I am currently running Debian Wheezy on a HP Microserver N54L with an AMD Radeon 5450 video card. I would like to be able to play audio from the console through the HDMI port of my video card and ...
2
votes
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 ...
14
votes
3answers
18k views

How to disable USB autosuspend on kernel 3.7.10 or above?

I've updated my HTPC from kernel 3.7.10 to 3.10.7 and it seems CONFIG_USB_SUSPEND is now gone from the kernel options and included in PM. The main problem I'm facing is that I have an external HDD ...
3
votes
1answer
58 views

What does “kernel:NMI watchdog: BUG: soft lockup” followed by other errors mean?

I have my terminal always opened (Fedora 22), because all my work I do from there. Sometimes I search some info in browser or just have fun. After 20-30 minutes of browsing (browser starts not from ...
2
votes
2answers
79 views

How to call in a kernel level function in user space [closed]

I've developed some helper functions in the kernel. They're called by other functions in the kernel. Currently, they make my custom kernel panic :( For now (i.e. debugging), I made them as a passive ...
1
vote
0answers
35 views

Automatic solution to reduce Linux kernel package size at compile time

Are there automatic solutions to disable unused Linux kernel parts (in particular unused modules) before compilation to fasten compilation? A daemon, that logs used kernel functions (or modules) at ...
3
votes
2answers
2k views

running kernel on QEMU

I face this message: Failed to execute /initKernel panic - not syncing: no init found. Try passing init=option to kernel. I am using this command line: qemu-system-x86_64 -hda disk.img -kernel ...
1
vote
0answers
16 views

Signing a module for prebuilt kernel

I am developing linux driver for my own PCI device. I have stucked up on starting my module: [14941.205599] mymod321: module verification failed: signature and/or required key missing - tainting ...
1
vote
0answers
25 views

Linux: Two differen drivers for two (mostly) identical PCI devices

for some obscure reason I want to use two different drivers for two identical PCI devices on the same system. The drivers have different characteristics, which is why I want one physical device ...
1
vote
0answers
45 views

How do I crash Ubuntu Linux 14.04 LTS deliberately?

I'm trying to crash an instance on AWS so I can simulate what happens when it gets 'stuck'. I tried the top suggestions here How to cause kernel panic with a single command? but unforunately they ...
0
votes
1answer
31 views

Does Parallels support 3.18.0-kali3-amd64?

I'm not able to find information on which kernels Parallels supports. I'm trying to figure out if Parallels 10.1 supports this kernel since Parallels Tools will not install no matter what I try. ...
1
vote
0answers
5 views

Opening/Writing to a file from a KProbe handler [migrated]

I am writing a Linux kernel module using Kprobes to trace specific system calls, and I need to write to a file from within a KProbe handler (specifically, a Kretprobe). I know this is generally not ...
0
votes
1answer
12 views

Use of MODULE_FIRMWARE(filename) macro in Linux modules

What is the use of the MODULE_FIRMWARE(filename) macro in Linux kernel modules?
9
votes
0answers
264 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 ...
4
votes
0answers
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: ...
0
votes
1answer
653 views

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 ...
0
votes
1answer
43 views

Empty kernel directory but kernel-headers are installed

Host - Windows 7 Guest - CentOS I am trying to install kernel-headers using yum since during the installation of vmware-tools I get a message asking for the path to the kernel header files for the ...
1
vote
1answer
545 views

Why system call hooking produces different result everytime in Linux/Android 2.6.29?

I have implemented system call hooking for Android 2.6.29 kernel through a LKM module. I am tracing down one Android app for system calls. But interestingly, it returns different results every time I ...
3
votes
1answer
1k views

Scaling issues of i7 3520M with intel_pstate module on Kernel 3.10.0

Few days ago I updated my openSUSE 12.3 system from Kernel 3.9.8-1.gf3348a8-desktop to 3.10.0-1.g3dcd746-desktop and since then, turbo mode of my i7 3520M is enabled by default and it does not ...
0
votes
1answer
62 views

Kernel version not changing even though the new version is installed

Recently performed software update on a RHEL 6.6 (Santiago). Noticed that kernel version is not updated to latest one that was installed. kernel version before doing software update: [root@server01 ...
1
vote
0answers
39 views

How to debug a kernel panic on boot with archiso?

I have an iMac mid 2011 running OSX and I am trying to install Arch Linux following this guide. I successfully set up a dual boot last year following a similar procedure but now I can't even start ...
3
votes
1answer
33 views

Why am I able to write a module parameter with READ ONLY permissions?

I wrote the following simple linux kernel module to test the param feature: #include<linux/module.h> int a = 5; module_param(a, int, S_IRUGO); int f1(void){ printk(KERN_ALERT "hello ...
1
vote
0answers
16 views

How to Dtrace a newly added function to the Kernel [closed]

I'm on Solaris 11. I'm writing various functions which will sit in different places in kernel. I need to watch the value of their internal variables for debugging purposes. For instance, the following ...
6
votes
2answers
806 views

Asus X101H - Touchpad not recognized (want to disable while typing)

I have been struggling with this issue for a while and have done an exhaustive search for answers here and elsewhere before posting this question. On my Asus X101H, the touchpad is not recognized as ...
1
vote
2answers
44 views

Linux fails with starting on a dualboot system after Windows update

I have Windows 7 and Kali Linux on my computer, normally I don't use windows anymore. But today I started windows and it updated itself. I am writing my thesis and all my stuff is in Linux so I really ...
21
votes
3answers
42k views

What's the difference of dmesg output and /var/log/messages?

AFAIK dmesg shows information about kernel and kernel modules, and /var/log/messages also shows information produced by kernel and modules. So what's the difference? Does /var/log/messages ⊂ output ...
6
votes
3answers
11k 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
38 views

kstat in Solaris 11+

I'm writing a kernel-level program in Solaris that monitors the workload of the system and reports the stats --something similar to netstats in linux and kstat in Solaris. Where the source code for ...
-1
votes
0answers
16 views

Which module utilities are the conf files in /etc/modprobe.d consulted for?

Are the conf files in /etc/modprobe.d consulted only for modprobe command or are they consulted for other module utility commands such as insmdod, rmmod, depmod etc as well? I found it mentioned in a ...
1
vote
0answers
27 views

Advice on printing in kernel [closed]

What is general advice on printing in kernel level? Lately, I need to print out some internal variables in various places. However, I use a naive way using printfk to dump the stuffs I need in log ...
1
vote
1answer
37 views

Why doesn't the Linux kernel prioritize interactive programs?

I've noticed that when running at 100%, things like GNOME become less responsive until I kill background tasks that are expected to take a long time, like compilation or downloading email. Why ...
1
vote
2answers
514 views

Cannot mount eCryptfs

I tried to install eCryptfs on my server to open an eCryptfs I did on my home computer. I got these errors. $ sudo mount -t ecryptfs /home/(place)/enc/ /home/(place)/enc/ Unable to get the ...
2
votes
0answers
27 views

File permissions for kernel have changed in OSX Yosmite, why?

I am working my way through the book Learning Unix for OSX Mountain Lion (I don't have access to the updated version for OSX), in which it demonstrates that using $ ls -l /mach_kernel should ...
2
votes
0answers
20 views

Significance of Linux kernel's default_console_loglevel

What is the significance of default_console_loglevel in Linux? Commonly I see it described as the default value of console_loglevel. However, what that means I haven't seen explained anywhere. ...