The linux-kernel tag has no wiki summary.
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Invoking memory compaction on linux 2.6.35 kernels and beyond
This LWN article about memory compaction indicates that memory compaction can be invoked in the linux kernel by
Writing a node number to /proc/sys/vm/compact_node, causing compaction to happen on ...
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1answer
88 views
How can I disable IPv6 in custom built embedded setup
I have an embedded system built using buildroot. I have had a number of network issues, one of which is that my machine cannot see its gateway despite it being on the same subnet. I have tried using ...
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1answer
86 views
core dump help— linux
I'm trying to understand the core dump generation. Is the core dump generated separately for a user space application process crash and the kernel level crash? Is the ulimit -c for both kinds? Can you ...
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2answers
91 views
swap partition and its laws
I remember for choice of swap partition, we should use (swap > 2xRAM) at least.Of course it deprecated , because max of computer's ram is very high. kernel support it.
My question: i remember each ...
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Best way of updating Openssl on Linux machine [duplicate]
I have a confusion to choose the best way for upgrading the OpenSSL on my Linux machine.
1*Through the yum Update.*
# yum update
I know this will update the entire packages. But If I want to ...
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0answers
134 views
Is it possible to run any distro from RAM from within an .iso saved on an NTFS file system?
Running entirely from RAM been done on various distros such as Slax, DamnSmallLinux, and newer Ubuntu versions, and since I have 8GB it seems reasonable that I could run many distros entirely from RAM ...
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0answers
65 views
Update jiffies value after waking up from suspend
The global variable jiffies holds the number of ticks that have occurred since the system booted. On boot, the kernel initializes the variable to zero, and it is incremented by one during each timer ...
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3answers
248 views
Disadvantages of linux kernel module?
I am trying to understand the disadvantages of using Linux kernel modules. I understand the benefits of using them: the ability to dynamically insert code into a running system without having to ...
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0answers
67 views
Is there any ARM platform for which high resolution timers are available in mainline (unpatched) kernels?
I currently have some projects using a TS-7400 board, which has a Cirrus Logic EP9302 ARM9 processor. Some of my applications require a 1ms periodic timer, so after lots of struggling I found these ...
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7answers
1k views
Why does mount require root privileges?
Why does Linux require that a user be root/using sudo/specifically authorized per mount in order to mount something? It seems like the decision as to whether to allow a user to mount something should ...
1
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1answer
117 views
Change of real time priority made no visible effect
we were trying to get the best result with software PWM on raspberry pi with Raspbian. We made a python script which starts PWM on a GPIO pin, and observed the results with the oscilloscope.
It ...
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0answers
110 views
How customize initrd via linuxrc
I have the need to use the same disk and so the same bootloader on devices with different motherboard.
Each motherboard has it's own way of mapping devices so sometime the bootdisk is mapped ad hda ...
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1answer
59 views
User Mode Linux compile fails
I am trying to compile User Mode Linux on a 64 bit machine with defconfig and getting the following error.
arch/x86/um/user-offsets.c:1: sorry, unimplemented: code model "large" not supported yet
...
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0answers
65 views
How to setup an audio/sound output monitor/listener?
I am working with an Arduino and am trying to get it to respond to sound when it is played on my computer. I'm communicating with it over a serial port.
I need to know if there are any audio/sound ...
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1answer
26 views
USB_HID is not working
How do I get a usb keyboard to work? I have already selected and compiled the USB HID transport layer and I don't know what else to do.
2
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0answers
38 views
kgdb not returning control to gdb
I've compiled a kernel with kgdb support and I'm trying to debug it. I have two machines running, a debug machine (running the kgdb kernel) and the machine I'm using to debug it. They are connected ...
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1answer
249 views
make: *** No targets. Stop while building linux kernel module [closed]
I am just trying to learn how to driver modules for Linux Kernel. I followed Linux Device drivers 3rd edition book and started my work. I created a sample program and makefile. Please find my makefile ...
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1answer
148 views
USB3 Hard Drive Not Recognised by Linux
My external USB 3 hard drive is behaving very strangely:
If I plug it into a USB 2 port, it works fine
If I plug it into a USB 3 port, it doesn't work at all. It's not even mentioned in ...
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3answers
179 views
AES-NI on Dell Vostro 3360
I don't have AES-NI available on my Dell Vostro 3360 laptop. Why? Does this machine not support it?
My /proc/cpuinfo:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 58
...
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2answers
330 views
Where can I find a good tutorial for installing bcache? [closed]
I found on the net and it's all too complicated.
http://bcache.evilpiepirate.org/ for example seems like the official page for bache. Yet nothing is found there. How to install? How to set up? ...
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1answer
111 views
Linux kernel 3.2 syscalls
Just trying to get the assembler instructions for <__execve> of the code below because i want to build the shell spawn opcode list:
#include <stdio.h>
int main()
{
char *happy[2];
...
1
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1answer
90 views
How to compile linux kernel and debug with gcc and BOCHS?
I have download bochs 2.6 sourcecode and installed with gdb-stub configuration. I would like to debug linux-kernel 1.0 or 2.0 or 3.0 which sourcecode downloaded from http://www.kernel.org/ with gcc ...
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3answers
248 views
Linux Kernel: uid and gid vs /etc/passwd
How does the Linux kernel deal with UIDs and GIDs?
When I want to add a user to a system, does the kernel require some type of "registration" for this user (syscall?)? Does the kernel even care about ...
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1answer
354 views
Kernel and QEMU : Unable to mount root fs error
I am trying to run a distro in the virtual disk image with a custom kernel,so that I can experiment and debug the kernel. I followed this to make a disk image and then install Debian to it. Now I ...
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4answers
375 views
Linux on a 286?
I don't own a 286 nor do I intend to run Linux on one. However since the 286 has protected mode, why is it frequently stated that Linux requires a 386 CPU or higher?
From ...
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0answers
510 views
mounting udev on /dev failed: No such device
I am trying to compile Linux kernel 3.2.36 with its source code on the x86_64 architecture. I followed the following set of commands under my Linux source distribution directory:
make defconfig
...
2
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1answer
370 views
Debugging Linux Kernel with QEMU
I was trying to study the debugging of kernel using QEMU. I tried initially and failed due to the fact that there was no virtual file system. The answers to this post suggests that there should be a ...
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3answers
385 views
Why is the theoretical RAM limit for RHEL 6 128 TB and how is this determined?
I'm studying for RHCSA and am confused by a statement I came across in some training material:
There is no practical maximum RAM, as theoretically, you could run 128 TB of RAM on RHEL 6. But ...
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0answers
152 views
Where does the Linux kernel reside in memory ?
From some book I have, I have in my notes that the Linux kernel resides at 0xc00000000 on 32-bit systems, and is mapped into user space for performance reasons.
Is this accurate ? How can I verify ...
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0answers
67 views
Android strace error: “strace: 2: Syntax error: ”&“ unexpected”
I was using built-in strace given in /system/xbin/ directory in the emulator and it was giving me wrong set of system calls such as msgget() and msgrecv() which are not supported by Android even.
I ...
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0answers
63 views
Linux, Debugger program development
We are trying to implement the debugger program which will takes either PID or Program name as input and Invoke the gdb by using PID. Below is two small programs are written, Not able to figure out ...
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2answers
535 views
After removing linux Grub error
I have a dual boot Windows & Linux system. I removed the Linux partition, but after that I am not able to go in to Windows XP. It is not booting. It gives me a GRUB error.
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How to solve linux kernel 0.11 loading system reboot automatically? [closed]
I use ubuntu 12.04 32bits in virtualbox.
I follow this link
I use this src
I make success to generate Image and System.map.
The special step I do is in fs/exec.c:
Origin:
139 ...
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0answers
76 views
Creating a Virtual filesystem to boot linux
I am trying to boot the linux kernel (bzImage) in QEMU but have had issues. After asking on U&L I found out that my problem was that I was booting the kernel without a filesystem to boot from. So ...
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1answer
203 views
Automatic kernel configuration tool
Is there any developed automatic linux kernel configuration tool?
I have found a method of make localmodconfig, but it is certainly very limited. I have searched the web but unfortunately have not ...
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0answers
69 views
What changed in Linux kernel (2.6.22) that gives hdparm support for power-on in standby?
Hdparm man page lists for parameter -s:
Enable/disable the power-on in standby feature, if supported by
the drive. VERY DANGEROUS. Do not use unless you are abso-
...
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0answers
247 views
CFLAGS in Linux kernel makefiles: which one is used when?
I'm not familiar with Makefiles, I can kinda understand them, but with the Linux Kernel I have a question.
(Using 3.7.1, Patched with BFS so line numbers may be a bit off)
On line 248
HOSTCFLAGS ...
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2answers
360 views
How to set OOM killer adjustments for daemons permanently?
Running some Linux servers with single or just a few vital system service daemons, I would like to adjust the OOM killer for those daemonized processes in case something odd happens. For example, ...
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2answers
273 views
How is a Linux kernel capable of accessing its assigned initramfs/initrd?
I'm trying to understand the boot process of a machine as a whole from the time you hit the power button. There's this one piece from bootloader to initramfs stage I don't quite understand among some ...
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0answers
43 views
Would it be possible to not have the network link cycled on loading the kernel module?
Using some cheap hardware in a thin-client setup we use a diskless PXE booting a small Linux kernel. Currently, it takes a quite some time to boot it fully up and we're looking into some optimizations ...
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2answers
196 views
Finding out the values of kernel options related to sysctl.conf and sysctl.d
On my Ubuntu machine, in /etc/sysctl.conf file, I've got reverse path filtering options commented out by default like this:
#net.ipv4.conf.default.rp_filter=1
#net.ipv4.conf.all.rp_filter=1
but in ...
2
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1answer
104 views
directions about customized Layer 2 implementation in linux
I have some machines running on the same network. One node is the control node which distributes traffic coming to it to the other nodes. The thing is that I want to have a custom protocol header ...
2
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1answer
125 views
Chain loading kernel without a boot loader
I am working on an embedded project that will do in-place upgrades. There may come a time when an upgrade will need to reinstall everything. Since this is a pretty risky thing, I would like to have ...
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0answers
58 views
Further clarification as to whether interuppts are disabled in top-half handler or not [closed]
Recently I came across a note in an online post that states the following:
In modern kernels, most of the differences between fast and slow interrupts have disappeared. There remains only one: ...
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0answers
4k views
Enabling IOMMU in the kernel for graphics card pass-through
Short question:
How can I turn on the intel_iommu setting in the Linux kernel? I run a Debian host, using the grub2 bootloader. Documentation I've seen says to edit /boot/grub/menu.lst, which seems ...
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1answer
171 views
Is TRESOR included in the latest kernel?
Did TRESOR get included in the
mainline Linux kernel? Where would I look to find out? Is there any documentation describing its use? Reading about cold boot attacks on Wikipedia makes me think TRESOR ...
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1answer
177 views
is linux/compiler.h a userspace header?
VirtualBox is looking for this file in /usr/include but it's missing in gentoo linux-headers
Does someone know if that is userspace header and gentoo is missing it? Or if that is not it, then if ...
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2answers
908 views
How to build a custom kernel on Fedora?
I want to test an (upstream) custom kernel on Fedora.
The plan so far is:
use a recent fedora config as starting point, e.g. /boot/config-3.6.6-1.fc17.x86_64
lookup build dependencies
lookup right ...
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1answer
53 views
What mode of memory at the time linux kernel was loaded?
Can anyone tell me what the memory mode is at the time linux kernel is loaded (by bootloader)? As this link says, the memory mode is real mode then the linux kernel will ask user to choose video mode ...
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2answers
436 views
exec() and system() system calls
I do understand that while exec() does not return after it executes in Unix ,system() may or may not return depending on the situation.But can anyone explain why exec() system call does not return and ...
