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

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Uname gives unfamiliar timestamp for kernel

I'm recompiling a new kernel (adding some debugging info) on Ubuntu by doing the following: make vmlinux; make install; after this I do a reboot and select my new custom kernel from the list. ...
2
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1answer
70 views

RedHat Enterprise Edition Kernel Support

Is there support for Kernel versions 2.4-2.6 in RedHat Enterprise Linux versions 4 and 5?
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1answer
204 views

How do I know which files will be included in a linux kernel before I build it?

I am working on a project that includes building an old kernel version of linux. This is fine, but I still need to patch the kernel of all previously found security vulnerabilities based on CVEs. I ...
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1answer
1k views

description of linux kernel boot parameters 'real_root' and 'cdroot'

I am looking for a formal description of the following boot parameters in the linux kernel: real_root cdroot I have problems tuning them to create my own bootable LiveUSB system. Are they ...
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2answers
1k views

How can I test a kernel module in a mobile device?

I'm writing a module for the Linux kernel. When this module is ready, I'd like it to run in any device running the kernel. How can I test it in an Android phone? Do I need to recompile the whole tree ...
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3answers
2k views

How to check if CONFIG_HIGH_RES_TIMERS enable?

I have to program a realtime application on Linux, but don't know whether the standard installation of Ubuntu has CONFIG_HIGH_RES_TIMERS enabled. How can I check this? I'm using Ubuntu 11.04 64bit.
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2answers
3k views

Kernel Mode Setting vs. Framebuffer?

With KMS, the graphics drivers are moved into the kernel. Since the framebuffer was already in the kernel, I wouldn't expect this to affect framebuffer operation. Yet, I read that KMS supercedes the ...
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1answer
126 views

Config setting for Linux kernel compilation

I need a Linux kernel compiled with debug features for a kernel module development.What all debugging configuration options should I include for kernel compilation,So that I can avail to all available ...
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5answers
13k views

Who's consuming my inotify resources?

After a recent upgrade to Fedora 15, I'm finding that a number of tools are failing with errors along the lines of: tail: inotify resources exhausted tail: inotify cannot be used, reverting to ...
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1answer
3k views

What happens the most, context switches or mode switches?

Which happens the most, context switches or mode switches? I have two answers myself, but I do not know which one is correct: Context switches happen in user mode, but this does not mean that a ...
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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.
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1answer
402 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 ...
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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 ...
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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 ...
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2answers
1k views

Documentation of kernel parameters

Where can I find a technical description of the kernel parameters listed in /proc/sys (ob Linux)?
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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
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1answer
186 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 ...
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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?
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1answer
28k 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 ...
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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 ...
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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
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1answer
11k 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 ...
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1answer
667 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 ...
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2answers
501 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 ...
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2answers
36k 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 ...
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0answers
995 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 ...
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2answers
1k views

List unused module

Is it possible to list down unused modules? lsmod would only list down dependency by modules, right?
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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 ...
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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 ...
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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 ...
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2answers
23k 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 ...
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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 ...
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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. ...
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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 ...
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1answer
797 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.
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1answer
351 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
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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 ...
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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 ...
19
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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 ...
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2answers
614 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 ...
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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) ...
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1answer
759 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
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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?
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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 ...
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3answers
825 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 ...
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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 ...
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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?
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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 ...
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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
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2answers
844 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 ...