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

learn more… | top users | synonyms

3
votes
1answer
164 views

Preemptive kernel and Physical Address Extension

Is there anyone that can tell me why, on a preemptive kernel, PAE would not work? This question is an exam question, however I haven't got a clue why it would not work.
1
vote
1answer
407 views

What are the Implications of moving to Huge mem kernel on RHEL4

I've been asked to investigate adding extra memory (> 16gb) to a RHEL 4 server and moving to a huge mem kernel. The server is used for Oracle RAC. Is it just a case of installing the hugh mem kernel ...
2
votes
1answer
5k views

NVIDIA installer can't find kernel source/build files (compiled from kernel.org)

I just compiled and installed the new 3.0-rc2 kernel from kernel.org on my Fedora 15 system. Everything seems to work fine and I can successfully boot into the system. However, this broke my ...
1
vote
2answers
483 views

Status of adding Reiser4 to the Linux kernel

I used the Reiser4 fs for some time and would love to see it get into the mainline kernel. I would think the project can still go forward even if Hans is not able to contribute these days. Is there ...
5
votes
2answers
1k views

Documentation of kernel parameters

Where can I find a technical description of the kernel parameters listed in /proc/sys (ob Linux)?
3
votes
1answer
354 views

Kernels of different distributions of Unix and of Linux

I have heard that different distributions of Linux have the same Linux kernel up to that the Linux kernels may be in different versions. Do different distributions of Unix also share the same kernel ...
2
votes
1answer
187 views

Which Grub to use for a custom portable boot image?

I would like to make a bootable USB/Floopy/LiveCD with linux kernel and Grub. After booting to that USB/Floopy/LiveCD using VirtualBox or directly, it will show my own customized Grub screen and then ...
7
votes
1answer
5k views

Do I need root (admin) permissions to run userspace 'perf' tool? (perf events are enabled in Linux kernel)

Do I need to have to run perf userspace tool as system administrator (root), or can I run it (or at least some subcommands) as an ordinary user?
26
votes
1answer
29k views

What is kernel ip forwarding?

I have seen on many blogs, using this command to enable IP forwarding while using many network security/sniffing tools on linux echo 1 > /proc/sys/net/ipv4/ip_forward Can anyone explain me in ...
1
vote
1answer
385 views

Fedora 15 - Limited RAM Access

I have an issue with Fedora 15's available memory. The laptop it is installed on has 4GB of SDRAM, but Fedora only sees 2GB. [njozwiak@calvin xpmc6720]$ free -m total used ...
6
votes
4answers
6k views

Prevent claiming of novelty usb device by usbhid so I can control it with libusb?

I have a USB rocket launcher that I wish to experiment with through libusb. However, libusb cannot claim the interface; presumably because the output of usb-devices lists 'usbhid' as the driver for ...
5
votes
1answer
12k views

How to check that perf events are enabled in Linux kernel, and how to install perf userland as non-root?

From what I have checked it looks like kernel side of 'perf' subsystem is enabled on computer I work on. Checking kernel configuration shows the following $ zgrep "_PERF[_= ]" /proc/config.gz ...
2
votes
1answer
671 views

Help in setting up internal Bluetooth card on Linux 2.6.38

I have a laptop that has a Bluetooth card in it, a Gateway NV series one. I'm trying to get it to turn on, as it currently isn't. The first time I booted after I wiped my drive and installed Linux ...
3
votes
2answers
506 views

Need for thread_info structure in Linux 2.6 Kernel

Prior to the Linux 2.6 kernel, struct task_struct was present at the end of the kernel stack of each process. There was no thread_info struct concept. But in Linux 2.6 kernel, instead of task_struct ...
75
votes
2answers
39k views

Kernel inotify watch limit reached

I'm currently facing a problem on a linux box where as root I have commands returning error because inotify watch limit has been reached. # tail -f /var/log/messages [...] tail: cannot watch '/var/...
2
votes
0answers
1k views

Linux kernel slab usage growing on embedded system

I'm in the process of QA/debugging a project on a custom embedded linux system. The problem we're VERY tight on memory, and even a couple megs can cause issues with our software. What I'm seeing (...
5
votes
2answers
1k views

List unused module

Is it possible to list down unused modules? lsmod would only list down dependency by modules, right?
6
votes
2answers
1k views

Proprietary or Closed Parts of the Kernel

I've heard of lines of code that are distributed with the Linux Kernel that aren't open. Maybe some drivers or something like that. I'd like to know how much of that is true? Are there lines of code ...
4
votes
1answer
1k views

Use aes-ni in Debian

I am considering building a small home server. I'd like to encrypt some folders on this server, therefore using the instruction set aes-ni which is supported by newer (mostly Intel) chips would be ...
13
votes
1answer
11k views

Description of kernel.printk values

Between Debian 5 and 6, the default suggested value for kernel.printk in /etc/sysctl.conf was changed from kernel.printk = 4 4 1 7 to kernel.printk = 3 4 1 3. I understand that the first value ...
28
votes
2answers
24k views

how to check rx ring, max_backlog, and max_syn_backlog size

Quite often in the course of troubleshooting and tuning things I find myself thinking about the following Linux kernel settings: net.core.netdev_max_backlog net.ipv4.tcp_max_syn_backlog net.core....
6
votes
4answers
4k views

Best way to get into Kernel programming?

Not so much asking what books (although if you know of any guides/tutorials that'd be helpful) but what is the best way to start doing kernel programming and is there a particular distro that would be ...
5
votes
3answers
9k views

Kernel panic - not syncing: No init found. While booting from U-Boot

Kernel mounted the root file system but can not find any init script. I'm sure that script exists in my ramdisk.img! I also checked out this and GE863-PRO3 U-BOOT Software User Guide 1VV0300777 Rev. ...
3
votes
3answers
13k views

possible to load kernel module that “disagrees about version of symbol”

I downloaded the sources for my kernel, applied a patch and rebuilt it and now I have a kernel module that, when I try to insmod, complains "Unknown symbol in module" with dmesg giving the error "...
2
votes
1answer
800 views

How to install a shared library in Linux

As part of my research work I have to study a rootkit. So I downloaded ncom rootkit and tried installing. It didnt have any installion files. Please help me in installing it.
4
votes
1answer
357 views

Where did Trampoline.S go?

Dear all, I was wondering where the trampoline code went. It is referenced here, and I could find some code in an earlier distro, but I can't find it in the 2.6.38 kernel. Can you explain to me the ...
2
votes
1answer
175 views

kernel patches - knowing when to do them

I've never done a kernel patch before, and I've just recently started looking into how it's done. I notice that for a patch's filename, it tells us the kernel version (i.e dm-raid45-2.6.25-...
4
votes
2answers
7k views

What is the difference between 32-bit PAE and 64-bit kernels?

I ask this only in regards to memory addressing. I know that a PAE kernel allows the OS to access more memory than a standard 32-bit kernel, however, what are the other implications? What specific ...
20
votes
1answer
21k views

How to use Linux kernel driver bind/unbind interface for USB-HID devices?

First background. I am developing a driver for Logitech game-panel devices. It's a keyboard with a screen on it. The driver is working nicely but by default the device is handled by HID. In order to ...
2
votes
2answers
617 views

[FreeBSD] rc.conf, loader.conf vs static kernel linking

I'm curious: What, exactly are the benefits to statically linking modules into the kernel rather than loading through rc.conf, etc? For example: To add linux emulation, I could add linux_enable="...
8
votes
2answers
4k views

What is the difference between likely and unlikely calls in Kernel?

What is the between likely and unlikely calls in Kernel. While searching through the kernel source i found these statements. # define likely(x) __builtin_expect(!!(x), 1) # define unlikely(x) ...
1
vote
1answer
772 views

What is the size of the TaskList?

While reading through the Linux Kernel Development by Robert Love, I went through the following line : The kernel stores the list of processes in a circular doubly linked list called the task ...
2
votes
2answers
128 views

What would it take for a *nix system to shutdown, then continue to grub?

Is this possible to shutdown to grub, not all the way so you don't have to load back up the BIOS and other things. Like to give you the ability to quickly boot for Linux to Windows?
17
votes
1answer
1k views

Rebooting without shutting off?

I have been using Linux Mint Debian with Debian unstable and noticed that when I press restart, instead of going all the way back to the BIOS, then grub, then booting up, I seem to be shutting down ...
5
votes
3answers
845 views

What would happen if a hard drive failed while the Linux kernel was running?

I've always been curious of what would happen if a hard drive failed while the Linux kernel was running. Since the kernel image itself is loaded completely into RAM, I don't imagine there would be any ...
4
votes
2answers
215 views

What potential ills can be brought by 'deleting' a live kernel?

I recently deleted my active Linux kernel and continued using the system as if nothing drastic happened. Are there any side-effects to deleting the Linux kernel that's currently in use? What about ...
4
votes
3answers
1k views

grub shows multiple kernel versions on startup

I have Ubuntu 10.10 and after few updates the boot menu lists many kernel versions. How do I remove older versions?
3
votes
1answer
304 views

How to compile a decent kernel from kernel.org?

I tried compiling a kernel from sources that I got from kernel.org (mainline) with make allyesconfig and make allmodconfig, but both builds resulted in a kernel, that won't boot. I was thinking, that ...
8
votes
4answers
3k views

IDE for large, multi-language projects (ie linux kernel)

I know the "which IDE do you guys use" question has been asked a million times. But I've never seen it asked in this context. What are some suggestions for an IDE when working on huge projects that ...
8
votes
2answers
849 views

Information about a laptop fan

Can you help me with finding all the hardware information (parameters) and configuration files about the fan in my laptop? I'm interested of the fan's parameters and configuration files that I can ...
2
votes
2answers
6k views

I am failing to build VirtualBox driver for Linux 2.6.38

I am running Debian 6, and decided to install 2.6.38 kernel from Unstable. I also installed the headers so that I can later on : sudo apt-get install --target-release=unstable linux-image-2.6.38-2-...
3
votes
1answer
116 views

sources for doing profiling of kernel portions?

Related to my previous post. I did not find any specific driver for which I can do profiling and benchmarking. However there is a one driver jffs2 filesystem for flash devices but I didn't know about ...
1
vote
0answers
164 views

Arch Linux not functional after kernel upate [duplicate]

Possible Duplicate: Arch Linux not booting after system update After running a system update, in which the kernel was updated, when I try to boot Arch (in single user, not quiet), I get the ...
3
votes
1answer
988 views

Compiled a Kernel (2.6.39-rc1), where is the corresponding initramfs?

as I've already wrote in the topic, I compiled a new Kernel with make defconfig, the bzImage is where it there, so is vmlinux.bin. I've installed modules with make modules_install. Now, what is the ...
10
votes
2answers
3k views

How to set a video mode in linux with kms/drm?

How can I set the video mode in Linux the low level way? As far as I know the lowest layer in userspace would be to request KMS via DRM. Is this correct? And if so, how could I achieve a mode switch ...
12
votes
2answers
2k views

Is there a downside to ksplice?

ksplice is an open source extension of the Linux kernel which allows system administrators to apply security patches to a running kernel without having to reboot the operating system. (From Wikipedia.)...
4
votes
1answer
2k views

Safe to delete System.map-* files in /boot?

I'm experimenting with generating some custom kernels using genkernel. However, each iteration leaves a file in /boot called System.map-genkernel-<arch>-<version>. Is it safe to rename ...
5
votes
1answer
645 views

Does IO prioritise by the very nature of renicing a task?

The CFQ IO scheduler supports priorities though I am not sure that Deadline does (I believe not). The premise is that when I renice a task it gets a larger share of CPU under the Completely Fair ...
10
votes
6answers
20k views

How does a kernel mount the root partition?

My question is with regards to booting a Linux system from a separate /boot partition. If most configuration files are located on a separate / partition, how does the kernel correctly mount it at boot ...
2
votes
1answer
1k views

Where is CONFIG_COMPAT_VDSO in make menuconfig?

I'm trying to compile a Linux Kernel to run light and paravirtualized on XenServer 5.6 fp1. I'm using the guide given here: http://www.mad-hacking.net/documentation/linux/deployment/xen/pv-guest-...