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

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How does Linux handle drivers when changing systems?

This has always made me wonder but how does Linux handle device drivers from system to system, so say you plug it in on computer A and then move to computer B with completely different specs. In ...
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41 views

Debian 8 crashes once every few days

I'm running Debian 8 on Linode 32 GB and once every few days the system crashes. This server is being used in productions and I need to find a solution ASAP The only server running on Debian is ...
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1answer
84 views

How is the IFB device positioned in the packet flow of the Linux kernel

I would like to know the exact position of the following device in the packet flow for ingress traffic shaping: IFB: Intermediate Functional Block I would like to better understand how packets are ...
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17 views

Build and install kernel module into a defined /lib/module/*kernel directory

I hope someone can help. I had problems with my distribution's kernel, so I built a kernel (same version) to build my modules. My modules would be compatible. However, if I install the modules, the ...
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36 views

How to enable additional audit logging?

We use Auditd to monitor specific changes on Linux systems. Majority of our rules come from CIS Benchmark guidelines and then few are added specifically to monitor certain command executions. We have ...
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1answer
31 views

Can't find CONFIG_PCI on menuconfig

I'm trying to enable the CONFIG_PCI option on a custom kernel I work with, but can't find the option. Searching from the menuconfig screen, I see that CONFIG_PCI should be located under the 'Bus ...
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51 views

Round Robin vs FIFO

recently I had to do some reports about scheduling processes in Linux, and to do so, we were asked to turn off all cpu except 0 to show how processes are running for cpu. But there is one thing which ...
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1answer
42 views

Does linux stops processing related to GUI when we remove the desktop screen from connection from cabinet(CPU box)?

When there is big non interactive software running and if I required more processing power then, after removing the desktop screen does kernel stops processing related to GUI(graphical user interface) ...
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31 views

Does anyone use Netem anymore? Alternatives?

When simulating an IP network you can use Linux built-in network emulator Netem. Together with bridge-utils of course. Simulating packet drop, duplicate packets, jitter et cetera. Is anyone using ...
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What are the differences between Debian Linux Kernel and Linux-libre?

What are the differences between Debian Linux Kernel and Linux-libre in terms of freedom related issues? I know the Debian Linux Kernel can load non-free modules while in Linux-libre they have been ...
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52 views

How to turn off stack protector in linux kernel easily? [duplicate]

I wrote a simple module for the Linux Kernel and it has a stack buffer overflow vulnerability. I want to exploit the module, but I have to turn off the stack protector in the kernel first. How could I ...
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1answer
44 views

How to debug Linux hang?

We are using beagle bone black based custom board, with kernel version 3.12. We are facing system hang during one of the init script,(Which brings up WiFi) this hang happens after random number of ...
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1answer
112 views

check if the Linux kernel my PC runs has been maliciously modified

$ uname -a Linux mypcname 3.16.0-4-686-pae #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08) i686 GNU/Linux I want to check that this ^^ Linux kernel on my PC has not been maliciously tampered with. I have ...
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2answers
38 views

What is maximum size of any memory segment goes in real life coding?

I'm reading about the x86, In that they have mentioned segment size can go upto 4GB (in 32-bit) architecture. Does anybody knows or experienced the segment size going beyond limit? Or upto what ...
2
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1answer
14 views

Pthread scheduler scope variables?

I read that their is 1:1 mapping of user and kernel thread in linux What is the difference between PTHREAD_SCOPE_PROCESS & PTHREAD_SCOPE_SYSTEM in linux if kernel is considering every thread ...
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0answers
18 views

WCHAN = 0 for a sleeping task?

I am a little confused about the status of a process I have. It looks like this: $ ps -eal | head -n 1 ; ps -eal | grep perf F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 4 S ...
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38 views

No keyboard input upon boot

I have just finished Linux-from-scratch (7.9). I followed the instructions exactly, and ran into no problems during the build. However, when I booted for the first time, it seemed to boot okay; it got ...
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34 views

Is this possible to use a different rootfs that the one kernel comes with?

Here's the situation: I have a compiled zImage that comes with its own rootfs that contains linuxrc. I can extract it using this script. I would like to modify some startup scripts that are part of ...
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27 views

Can Linux decapsulate double GRE encapsulation?

For an application when the packets arrive at the receiving host, those packets are double GRE encapsulated (IP Hdr + GRE Hdr + IP Hdr + GRE Hdr + payload packet). I am wondering if Linux kernel in ...
6
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1answer
63 views

Does linux do outer ip fragmentation

I am looking to understand if Linux has the capability to do fragmentation of the outgoing packets at inner IP or outer IP level? I looked the source code in /net/ipv4/files in Linux kernel source, ...
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1answer
19 views

How to find a specific patch for a kernel file

I've been debugging an issue in my linux kernel and have found a fix for the issue. Checking cross reference, I can see that the fix was applied to that file between kernel version A and kernel ...
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1answer
37 views

Linux kernel 3.14: Cannot find LILO

I'm trying to compile linux kernel 3.14 on ubuntu 14.04. Before anyone points out, I know newer stable versions of the kernel are available but I have been asked to install 3.14 itself. So, I wrote a ...
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2answers
29 views

Is there a way to determine compile-time state of a kernel flag from a running system?

I have a running kernel and I'm trying to determine whether it was compiled with support for BTRFS extended attributes. Is there a way to determine a running kernel's compile flags?
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60 views

How do Linux kernel modules get enabled in a Linux distro's kernel package?

Although I know how to recompile my kernel to enable a module I want, I'm curious to know how the default Linux kernel modules are chosen in a Linux distribution's kernel package. Taking a comparison ...
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Mint + Kernel 4.5.4: laptop loses suspend state when unplugged

I'm using Linux Mint 17.3 on a newish Asus laptop with Mate desktop. To get the Nvidia graphics and Elan touchpad both to work, I installed the 4.5.4 Linux kernel. I've pretty much got everything ...
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24 views

Strange PFN read from pagemap

I m trying to find the physical page to which a range of virtual addresses are mapped in a piece of C code that I ve written. I m using the /proc/self/pagemap to read the mapping. I ve used the code ...
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22 views

Raspberry pi blocks completely after multiple reboots

I have a c++ program running on login on the raspberry pi, this program checks data for multiple devices attached on to it (Arduino Mega 2560 + Modbus RS485), gets inputted data from them and sends ...
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1answer
26 views

Libraries and linux Kernel 2.6

Which command i can use to see what my current installed software libraries use from the Kernel 2.6? I want to know this so I can check if it would work fine in case I upgraded my Kernel to 3.1.
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1answer
48 views

psmouse kernel module recompiling

I have a ultrabook and its touchpad doesn't work. Linux mike 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-1 (2016-03-06) x86_64 GNU/Linux touchpad doesn't work and it is also not listed in output of ...
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39 views

External Fragmentation in FreeBSD due to unmovable Kernel pages

Is external fragmentation an issue in FreeBSD due to unmovable Kernel pages similar to what Linux (1) (2) faces?
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41 views

Pagemap on memory mapped devices not working

I am trying to find the physical addresses of heap variables, stack variables and memory mapped peripheral addresses using the /proc/{pid}/pagemap file using the steps detailed in the file: http://lxr....
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172 views

Kernel driver for trackpoint on Lenovo Thinkpad 13

On other ThinkPads I've succesfully configured the trackpoint with udev using this method but on my new Lenovo Thinkpad 13 this isn't possible: This command: find /sys/devices/platform/i8042 -name ...
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71 views

Screen glitches linut mint lenovo yoga 900 after Kernel 4.6 update

Installed mint 17.3 on my yoga 900, updated to kernel 4.6 to get touchpad, wireless card, and touchscreen working. Everything seems to be working okay other than the screen glitches, specifically on ...
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357 views

Ubuntu 16.04: How is the bonding kernel module gettting loaded automatically?

I recently set up an Ubuntu 16.04 system with a bonded ethernet configuration. Previously, it appears that to get this to work the bonding module needed to be included in /etc/modules or /etc/modules....
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24 views

lubuntu reduce size of vmlinuz file for PXE boot

I have poor knowledge about Linux systems, but Windows XP support is over. I have two older computers. I want install Lubuntu from PXE on this computers, but the problem is that they says "NBP is too ...
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1answer
18 views

Can making CPU-intensive processes lowest priority (19) have adverse effects?

When I make a CPU-intensive process lowest priority (niceness of 19), it seems the amount of real memory consumption goes up. Perhaps this has other causes. But, can making CPU-intensive processes ...
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81 views

Manjaro doesn't update syslinux.cfg when I install new kernels. How can it be done?

I have a fresh installation of Manjaro 15.12 (Capella) 64-bit on my Dell Latitude. I started with the CLI installer as I had a couple of LVM volumes to reattach to my system — such as /home and the ...
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2answers
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What is the Out of Memory message: sacrifice child?

My computer recently ran out of memory (a not-unexpected consequence of compiling software while working with large GIS datasets). In the system log detailing how it dealt with the OOM condition is ...
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68 views

Can't purge old kernels (dependency problems), but /boot is out of space

I'm running Ubuntu 14.04.4 LTS, and I'm trying to install a new package using apt-get. Unfortunately, whenever I try I get messages like: The following packages have unmet dependencies: linux-image-...
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1answer
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How do I run the Linux kernel?

I'm reading Robert Love's Linux Kernel Development in order to learn more about, well, Linux kernel development! But in Chapter 2: Getting Started with the Kernel, I'm instructed to download and ...
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1answer
40 views

understand chains and tables in netfilter/iptables

As I understand, Linux kernel has five hook points for IPv4 packet flow defined in netfilter_ipv4.h file: /* IP Hooks */ /* After promisc drops, checksum checks. */ #define NF_IP_PRE_ROUTING 0 /* ...
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1answer
101 views

understanding “bridge check” hop in packet flow in Linux kernel

According to "Packet flow in Netfilter and General Networking" drawing in Wikipedia Netfilter article: ..one of the first hops in packet flow right after the traffic control and queuing is bridge ...
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2answers
25 views

Is sysfs a strict subset of procfs? [duplicate]

Is the information that the Linux kernel provides to the user via sysfs a strict subset of the information that the Linux kernel provides to the user via procfs? If not, then which information is ...
3
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1answer
64 views

How does the kernel assign cpu ids to physical cores?

One may find a lot of info about how to inspect physical cores layout in a running linux system, but I'm wondering how the physical cores are assigned a cpu id in the first place. After experiencing ...
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1answer
56 views

Dracut failure when trying to boot Fedora with Qubes kernel

I would like to boot Fedora 23 Workstation x86_64 with a kernel from QubesOS 3.1. I have copied vmlinuz-4.1.13-9.pvops.qubes.x86_64 and initramfs-4.1.13-9.pvops.qubes.x86_64.img into the /boot ...
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31 views

Linux is crashing without throwing core dump or error message

I am working on a development board to make custom linux working(built through Yocto) on it. Right now, I am facing very weird issue. System boots and after some time it hangs and restarts without any ...
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1answer
46 views

Designing a new Operation System

I want to design a new OS to learn more about how an OS works. This OS is only for educational purpose and I had a few doubts choosing its kernel. Is there any legal issue for using an Ubuntu kernel?...
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Building kernel for BeagleBone Black lead me hdmi problems

I have successfully followed CLFS book to build RPi and BBB embedded systems. In RPi case the bootloader did not give me problems with device tree. Some years ago I would have to patch Torvalds' ...
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1answer
49 views

Linux Crypto API headers missing

As soon as headers are essential to deal with crypto algorithms, provided by kernel, I've installed linux-headers-4.4.0-1-amd64. However, this did not added files like crypto.h, module.h and init.h ...