This tag is for questions about the internals of the Linux kernel itself - particularly about use or configuration of kernel modules or drivers.

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9
votes
4answers
919 views

Does linux have any measures to protect against fork bombs?

#include <unistd.h> int main(int argc, char* argv[]) { while(1) { fork(); } } I run this program on my linux, nothing outputs on the terminal, the OS seems go dead. Does linux have ...
9
votes
6answers
16k views

How do I uncompress vmlinuz to vmlinux?

I have already tried uncompress, gzip, and all other solutions that come up as google results and these have not worked for me. To get just the image search for the GZ signature - 1f 8b 08 00. ...
8
votes
3answers
675 views

Compiling the Linux kernel

Just for the learning experience, I have recompiled the Linux kernel with different options, installed and booted from it. It was both instructive and straightforward. However, I was overwhelmed by ...
8
votes
1answer
5k views

Linux overcommit memory

I've been looking into memory overcommitting in Linux using /proc/sys/vm/overcommit_memory, and I've read a few articles which don't say the same thing. This doc, under the heading "Going in the ...
6
votes
2answers
7k views

how to totally clear the filesytem's cache on linux?

In a performance test, I want to bypass the influence of cache of linux system (including page cache/inode cache and so on). I have tried O_DIRECT flag, but it's turned out that direct I/O is still ...
6
votes
2answers
11k views

Linux kernel hangs at 'Switching to clocksource tsc" on Pentium 4

Hardware: Dell Dimension 4500S : i845G, Pentium 4, stock + 2GB RAM and latest (circa 2002) BIOS update. I've been building a Linux system from source, so far it's LFS 7.0 by the book. The first ...
6
votes
5answers
10k views

What does “sudo -s” actually do?

I am using ubuntu 10.04. I notice that after I run "sudo -s" in terminal, the prompt changed from "XXX@XXX" to "root@XXX", seems it changed to root privilege. But when I check the ...
5
votes
4answers
10k views

How to search by content on Ubuntu

I'd like to search the entire server by content. (text file) When I try grep -rl "text here", it freezes. How would you do it? And how long does it usually take?
5
votes
1answer
224 views

Kernel hacking methodology - how to find out where to hack the linux kernel

I have a throw-away cheap laptop I'd like to twiddle around, a Thinkpad SL 500. What bothers me are two leds, the one for wireless connectivity, and the one for hibernation, which don't light up at ...
4
votes
4answers
198 views

What steps do I need to take to compile and install a Linux kernel?

What are the correct steps to compile a Linux kernel? Are these steps the same or different for different kernel versions i.e for 2.2, 2.4 and 2.6.
4
votes
3answers
499 views

Pipe kernel messages to another process as they occur

I have an OLED screen on my laptop that I have configured to show status information. The current driver I have installed in Linux for it is able to display messages by sending them to a script as an ...
4
votes
2answers
421 views

Is it possible to boot a consumer i7 system with a Xeon processor and ECC memory?

I have read a couple of blog posts on the Internet that appear to imply one can boot at least some i7 motherboards with unbuffered ECC memory and a Xeon 43xx processor installed. I can boot my MSI ...
4
votes
1answer
559 views

Where did SELinux go?

I am compiling a new kernel, and want to enable SELinux but don't see it in menuconfig anywhere. The only framework under security options is Tomoyo.....so I ask, what happened to SELinux? Both ...
4
votes
2answers
53 views

How to remotely test the linux install CD for integrity

if you do, after the completing the test - it will eject the CD. and how are you going to reinsert the CD to complete your install? you're remote remember ??
3
votes
2answers
2k views

pinning process to a CPU

I wish to pin a process to a CPU1 in my dual CPU machine - how can I do it in Linux - any pointers ?
3
votes
2answers
1k views

Compile linux kernel for different machine

I am new to kernel development, and I have to compile a kernel with some specific features and then install it on some machines. The problem is that these machines are slow, and hence I want to ...
3
votes
1answer
4k views

Where can I find the Linux kernel file?

Is there any common directory to find kernel file in all Linux distributions?if yes please tell me how to browse to the directory? Where can I find the Linux file in Ubuntu & RedHat operating ...
3
votes
3answers
2k views

Unmounting Detachable devices (eSATA,USB storage) in Linux

A detachable device like eSATA, USB drive can be abruptly removed (by simply pulling the plug). If there are open file handles on a partition, then this partitions won't unmount, i.e. the Linux ...
3
votes
1answer
162 views

Should I compile the linux kernel in the git repository itself?

This is about common practices. I have a git repository containing the linux kernel. Now I want to build this linux kernel. Should I copy the sources outside the git repository and then build the ...
3
votes
2answers
2k views

How to get a list of active drivers that are statically built into the linux kernel?

While I can use lsmod in order to show currently active kernel modules, how can I see which drivers are statically built into the kernel AND currently active?
3
votes
1answer
416 views

Microphone not working on Apple Macbook Air 1,1 (Early 2008; A1237) under Linux

I'm running Linux on the MBA. I can't make the microphone work. I test using alsamixer and arecord -Dhw -fdat -vv mic.wav together with aplay -Dhw -vv mic.wav It seems there is a problem with Linux ...
3
votes
1answer
214 views

enabling CONFIG_LIBIPW on kernel compiling

I need to enable CONFIG_LIBIPW=m on kernel 3.4.0 I see that IPW2100, IPW2200, and PCI needs to be enabled, but I could not find any clue where they are on the menuconfig. I read on ...
3
votes
1answer
3k views

`cat /proc/kmsg` outputs broken text

cat /proc/kmsg is convenient way to follow kernel messages. But the output is unreliable. Example: < eoyfl-o-ilF ilaltssI hwflssesJ a hwbctaealatv-psL hwmmr-sg()nc-l-TtssN oeOfso-eitr()so-l-iesQ ...
3
votes
2answers
1k views

Install VirtualBox on Ubuntu 12.04.1 (on [Samsung] Chromebook)

I have dual booted Ubuntu Linux 12.04.1 LTS on my Samsung Series 5 ChromeBook, and am trying to run/install Oracle VirtualBox (from the generic .run file downloaded from their website). However, every ...
2
votes
8answers
4k views

Where is installed software stored in Linux? [duplicate]

Possible Duplicate: Where is a typical Linux program installed I'm new to Linux and I want to ask a bit more about packages. In Windows, I download an .exe file and install it. When I ...
2
votes
3answers
2k views

Is it possible to make the OOM killer intervent earlier?

I try to tweak my development system to maximal reliability. I disabled swap, because for GUI usage it mostly renders the machine unresponsive in such a way not useable anymore. Nevertheless, if ...
2
votes
2answers
315 views

What does this macro mean in linux kernel code?

see i found one config file in which this are macro defined # # Input Device Drivers # CONFIG_INPUT_KEYBOARD=y # CONFIG_KEYBOARD_ADP5588 is not set CONFIG_KEYBOARD_ATKBD=y # CONFIG_KEYBOARD_QT2160 ...
2
votes
2answers
6k views

How do I set up grub2 with Xen?

I am booting a new Xen kernel and it all goes fine up until some point during the boot process when the machine reboots without warning. Unfortunately, I don't see errors flash up just before that ...
2
votes
2answers
1k views

Linux: Disable loopback interface from kernel

I know it is possible to bring down lo interface by doing ifconfig lo down. But is it possible to configure the kernel that the lo interface will simply not be available? Please note that I don't want ...
2
votes
1answer
644 views

ZFS distribution in Linux kernel? [closed]

If anyone has a better title for this question feel free to edit I am wondering about something related to the conflict between CDDL (Sun's license) and the GPL. Mainly pertaining to the reason ZFS ...
2
votes
1answer
101 views

can /usr/src be a sym link?

I want to store all source code of programs I have installed in /usr/src. However, due to size of the drive I made a sym link /usr/src that points to ~/src. That was nice. Unfortunately, that caused ...
2
votes
2answers
2k views

lsmod and /proc/modules

I can get a list of modules using either lsmod or cat /proc/modules. Do the two approaches use the same mechanism to retrieve the modules? I want to know this as we could use it to find some hidden ...
2
votes
2answers
82 views

how do i switch custom kernels?

i have created and installed a new kernel in my ubuntu system, but now i have added a new system call and created a new kernel, how do i set this new kernel as the one the OS should boot from. dpkg ...
2
votes
1answer
64 views

Debian loses harddisk on bootup 4 times and then boots. Why?

Dmesg Dump: http://paste.debian.net/44975 at time 32.832045 That error is delaying my boot process significantly. Does anyone know what this is about? Devices: Maxtor IDE drive with new cable on ...
2
votes
1answer
238 views

GENTOO: disadvantages to using genkernel all?

I'm wondering, what are the disadvantages to using genkernel when I'm compiling a kernel in gentoo? Is it perfectly ok to use genkernel all in pretty much any situation, and skip this ...
2
votes
1answer
81 views

How is PAE implemented in Linux?

There are only 36 physical address lines but a page table entry is 64 bit long. How does the CPU check if the address is valid ? How does Linux OS map the same virtual address in different processes ...
2
votes
1answer
530 views

Out of space while bulding Linux kernel

I am trying to build Linux kernel. I am getting out of space after a while. I unpacked it in /usr/src directory. It seems I have plenty of space. Can you please let me know what can be done about it. ...
2
votes
1answer
117 views

How to make Linux reliably boot on multi-cpu machines?

I've got two machines, one with 4x12 AMD Opteron cores (AMD Opteron(tm) Processor 6176), one with 2x8 Xeon cores (HT disabled; Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz). On both machines I experience ...
2
votes
0answers
306 views

Why is the kernel and the watchdogs consuming all the CPU?

I run a bunch of heavy user space processes on a powerful Xeon machine (32 virtual processors according to /proc/cpuinfo). The CPU load is normally around 30 and the machine feel responsive, but later ...
2
votes
0answers
143 views

In Linux Driver, how to disable a specific USB Device [closed]

Assume a USB devices is powered by USB bus. Sometimes the firmware in the USB device encounter a problem and can't recovery by itself. I have to unplug and plug the USB device from the host. Is there ...
2
votes
0answers
80 views

How are ties broken in AuFS with the top-down-parent file creation policy?

The AuFS manual says: Policies for Creating create=tdp | top−down−parent Selects the highest writable branch where the parent dir exists. If the parent dir does not exist on a writable branch, ...
2
votes
2answers
2k views

AR9485 chipset support by linux kernel

The wireless in my Asus P8Z77-V Pro didn’t work (it’s a new machine, in which I installed Debian Linux 6.0.6, kernel 2.6.32-5-amd64), and since I’m not an advanced user, and knew naught about ...
2
votes
0answers
148 views

What does the linux kernel/initrd loading time depend on?

I recently updated my Linux kernel from 3.1.10 to 3.5.0. Upon booting with GRUB, I noticed that this kernel (or the initial ramdisk?) takes a much longer time to load (~5-6 s vs. ~1 s with the old ...
2
votes
0answers
192 views

Capture key events at system level to control e.g. alsamixer

In Linux window managers, it is easy to define actions for key events - e.g. in openbox: <keybind key="XF86AudioRaiseVolume"> <action name="Execute"> <command>amixer set ...
2
votes
1answer
115 views

Oracle Virtualbox on statically compiled kernel

I can't seem to find any documentation on the subject. I'm working on putting together a linux install for a fairly "dirty" environment. Best practice there would be a statically compiled kernel ...
2
votes
3answers
873 views

Running linux kernel 0.01 in a virtual machine

I'm just trying to know if is there is a way to run the first version of linux in a virtual machine. Since I am very new to this, my aim is to learn something basic on how the first version of linux ...
2
votes
0answers
225 views

Linux kernel 2.6 - layer 7 support?

From what I found on the Internet, Layer7 classifier support is not merged into the current kernel (as of 2.6.39-rc6) and can be achieved with a patch. Is it known when (if ever) the support will be ...
1
vote
2answers
375 views

Linux kernel compiling: standalone OS

Hi guys I'm new to linux kernel compiling so I have some question: By compiling linux kernel are we building a totally standalone OS which doesn't depend on any linux destributions? If yes... Well ...
1
vote
2answers
144 views

Linux boot parameters and hacking

Bear with me since I'm a linux noob... I had an assignment for a security class in which I was supposed to gain access to a file in on an administrator's desktop. I modified the boot settings by ...
1
vote
3answers
206 views

Linux How can I prove if udev installed?

How can I prove if udev is installed and working proper? Just call udevadm would be a method, right?