The kernel of operating systems popularly known as Linux, or sometimes GNU/Linux.

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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 ...
2
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2answers
214 views

How to edit grub2 to use kdump?

I was following http://fedoraproject.org/wiki/How_to_use_kdump_to_debug_kernel_crashes and in step 2 I need to add the line to grub.cfg, but grub.cfg is a shell I do not know how to edit it, most ...
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1answer
2k 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
206 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
957 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
298 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
5k 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 ...
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1answer
426 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
168 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 ...
4
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1answer
126 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
214 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
43 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.
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53 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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0answers
222 views

My SMDK2416 (for s3c2416) kernel works on 64MRAM but crashed on 128M

I'm currently working on embedded arm linux with smdk2416(s3c2416) The kernel is working on the 64MRAM. Recently, I need to increase the RAM from 64M to 128MB with 64MB on bank0 and 64MB on bank1. ...
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1answer
2k 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 ...
2
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1answer
468 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
359 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
2k views

Where can I find a good tutorial for installing bcache? [closed]

Question is updated. Now bcache is part of the standard OS compilation. So it should be easy to install that now. I'll just order some SSD and some big HDD. Where can I found it? I found on the net ...
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1answer
227 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]; ...
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1answer
215 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
624 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 ...
3
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1answer
2k 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
798 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
2k 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
846 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
4k 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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399 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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92 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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1answer
161 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
838 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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0answers
114 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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2answers
867 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
113 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
897 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
2k 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, ...
5
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2answers
1k 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
58 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
1k 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 ...
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1answer
132 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
359 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
85 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: ...
9
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3answers
16k 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 ...
2
votes
1answer
628 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 ...
2
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1answer
533 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 ...
5
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2answers
3k views

How to build a custom kernel? [duplicate]

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
65 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
1k 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 ...
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1answer
545 views

how to download linux kernel using rsync

I tried git clone, but it's too slow, how to do it with rsync? is it faster? If I do rsync rsync://rsync.kernel.org/pub/ it just shows: drwxr-sr-x 4096 2011/11/16 04:40:02 kernel
9
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2answers
8k views

How to boot EFI kernel using QEMU (kvm)?

Hey guys I'm trying to emulate a EFI enviroment using QEMU (kmv), virtualbox takes 15 minutes to boot in EFI mode using archboot. Using legacy BIOS mode I can boot using this command: ...
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2answers
386 views

Can't compile kernel in gentoo

I installed gentoo by the handbook from official site. When I got into the step 7.b. Installing the Sources, the book says: Code Listing 2.2: Viewing the kernel source symlink When you take ...