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

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routing table “220” in Linux kernel 3.2.0-23-generic

I have a Linux machine with kernel 3.2.0-23-generic and it has rule with priority 220 in RPDB which points to routing table named "220": T42:~# ip rule show 0: from all lookup local 220: ...
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1answer
176 views

routing cache in latest Linux kernels

As I understand, routing cache was removed since Linux kernel 3.6. In systems with older Linux kernel one could view the content of the routing cache with ip route show cache command and routing ...
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499 views

When a process forks is its virtual or resident memory copied?

The standard way of making new processes in Linux is that the memory footprint of (parent) the parent process is copied and that becomes the environment of the child process until execv is called. ...
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86 views

how to increase Stack Size of a running program in C

I am trying to identify any way if we can increase the stack size of my running program after getting SIGSEGV. I know we can increase the size of stack by ulimit -c but, that did not solve this ...
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27 views

Why my limit on CPU does not validate via cgroups

/etc/cgconfig.conf ... group memlimit { memory { memory.limit_in_bytes = 8589934592; } } group cpulimit { cpu { cpu.shares = 1024; } } /etc/cgrules.conf: ...
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1answer
79 views

How to enable random PIDs on Linux?

I'm currently comparing random PID implementation on OpenBSD, FreeBSD and Linux from security perspective. As long as OpenBSD and FreeBSD are concerned, my work is done. However, while the answer ...
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1answer
409 views

Understand logging in Linux

As I understand, Linux kernel logs to /proc/kmsg file(mostly hardware-related messages) and /dev/log socket? Anywhere else? Are other applications also able to send messages to /proc/kmsg or /dev/log? ...
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68 views

Triggering hardware interrupts by connecting parallel port pins 9 and 10 does not work

I want to trigger hardware interrupts as described in the book Linux Device Drivers by connecting pins 9 and 10 with a wire. I tried that but apparently there's no interrupt beeing triggered: cat ...
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1answer
61 views

Linux doesn't drop FS Caches. Instead Memory starts Swapping

I'm quite confused about this behaviour of linux memory caching. total used free shared buffers cached Mem: 15953 14188 1765 64 ...
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2answers
297 views

Linux does not reply to ARP request messages if requested IP address is associated with another (disabled) interface

I have a PC(kernel 3.2.0-23-generic) which has 192.168.1.2/24 configured to eth0 interface and also uses 192.168.1.1 and 192.168.1.2 addresses for tun0 interface: root@T42:~# ip addr show 1: lo: ...
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140 views

How to create Linux Kernel Headers from Linux Kernel Source?

I'm working with Tiny Core Linux and attempting to install Vmware Tools, which of course needs the Kernel Headers :-). It does not appear they have the Kernel Headers readily available in a package, ...
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96 views

How to resolve dracut problem when intall Fedora 21

I'm Ubuntu User. But I wanted to change my OS from Ubuntu to Fedora. So I wanted to Fedora 21. But there is a problem. I'm using USB Drive to boot Fedora 21. When I try to install Fedora I get a ...
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2answers
185 views

What are the programs/commands which the magic SysRq key invoke?

From Magic SysRq key The magic SysRq key is a key combination understood by the Linux kernel, which allows the user to perform various low level commands regardless of the system's state. It ...
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43 views

How SYN and ACK packets counted by the server(Linux)

I have a question about tcp layer of linux kernel. I want, Syn and ack packages received to server will be counted. where total_syn_count and total_ack_count are variables to be defined and will ...
4
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1answer
43 views

Do I have to publish kernel source if I release a custom kernel?

I have a kernel for an android phone ready for release. I always have the current source code already pushed to GitHub for release builds. However, I also have an experimental folder on my server ...
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74 views

SMB/CIFS mount not working with exec() call

To mount CIFS presently I use system() call in source, this works. If I try to run command manually on shell it works too. $ mount -t cifs //IP/dir /mnt -o user=name,pass=PASS,domain=mydomain,nounix ...
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112 views

Where is routing table stored internally in the Linux kernel?

When I execute route -n, from where exactly (from which structs) is the information displayed retrieved? I tried executing strace route -n but I didn't help me finding the right place it's stored.
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94 views

RHEL not booting with the updated kernel after upgrade [closed]

We have recently upgraded RHEL boxes, but the system only booted with the old kernel. Observation is that there is no link /etc/grub.conf to /boot/grub/grub.conf. Now, to boot the system with the new ...
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2answers
144 views

how to untar file in linux red hat?

I am compiling linux red hat stable kernel on red hat linux and the error which I am facing is as below
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19 views

Which linux kernel options need to be enabled to support bluetooth low energy?

Which are the mandatory and optional options?
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1answer
41 views

Kernel modules for compiled kernel

I cannot find kernel-headers. For the first time I compiled and installed the latest kernel (4.0.3) on my Debian Wheezy, and now I am trying to install ndiswrapper using module assistant. For that, ...
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36 views

Trying to use KDBG, but it produces error 11

I am trying to start kdbg on Ubuntu, but it produces this error message: MNG error 11: function is invalid at this point ; chunk MHDR; subcode 0:0 MNG error 11: function is invalid at this point ; ...
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105 views

How to read the output of the show-memory-usage SysRq?

I couldn’t find any (recent) documentation on reading the output of the show-memory-usage SysRq (Alt+SysRq+m). So what can one learn from looking at it? Here is an example output form my box (Kernel ...
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65 views

how to check a kernel version which was used when building package

I use apt when downloading packages from Ubuntu repositories. How can I check which kernel version was used when building package? When it is important (kernel version of the build server vs. kernel ...
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141 views

What is the difference between Local timer interrupts and the timer?

When I do cat /proc/interrupts on my multicore x86_64 desktop PC (kernel 3.16) I see this: 0: 16 0 IO-APIC-edge timer LOC: 529283 401319 Local timer interrupts ...
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1answer
216 views

Change hidraw device from mouse to joystick

I have a wireless PS3 controller adapter that is plugged in to my Ubuntu 14.04 box. It has 2 modes: XInput and DInput, which as far as I can tell, it just passes two different vendor/product id's ...
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95 views

How to get the mouse/keyboard raw events?

I want to intercept the raw events from the keyboard (or the mouse, eventually). I tried to use the /dev/input/[...] files, they are very practical and I can read the events of any key even caps lock ...
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19 views

Want a bash script for file system monitoring for multiple RHEL servers [duplicate]

I'm trying to prepare a bash script to monitor file system utilization for more than 80% on 20 RHEL 6 servers. Below is the script, #!/bin/bash ADMIN="abcd@zxy.com" ALERT=80 dt=`date '+%a %b %e %I:%M ...
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0answers
32 views

How to work with a kernel one has no information about?

I'm working with a system to automatically assemble Live CDs. It came packaged with a kernel (seemingly based on 3.13.11), that has been working without problems so far. I noticed that, when I try ...
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10 views

Having problems with negative monitor channel, intimidated!

When I try this command: aireplay-ng -1 0 mon0 -a xx:xx:xx:xx:xx:xx I get this output: No source MAC (-h) specified. Using the device MAC (xx:xx:xx:xx:xx:xx) 17:51:23 Waiting for beacon frame ...
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218 views

Ubuntu: freezing on startup

I recently installed Ubuntu 14.04 on a new ThinkPad laptop as a dual boot with Windows 8. It has been running for a few days without issue. However, when I booted my computer today, it got stuck on ...
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1answer
63 views

What is a sync during kernel boot?

If something prevents a Linux system from booting, it is common to see this message: kernel panic - not syncing: [Error Message] But what does "not syncing" mean? What exactly isn't syncing? The ...
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810 views

Is it possible to tell if my Linux kernel is custom (i.e. compiled) as opposed to distro?

Taking example of Ubuntu, can we tell if the kernel was custom compiled rather than what comes with distro?
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1answer
118 views

Understand Linux kernel virtual bridge port numbering

I have a Linux kernel virtual bridge which contains interfaces eth1 and tap0: # brctl show br0 bridge name bridge id STP enabled interfaces br0 8000.00016c404fa3 ...
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1answer
84 views

Debian: How to get the current loaded kernel package name?

With the following command, I can list all the installed kernel package: $ dpkg -l | grep linux-image With the following command, I get for instance the version of the current kernel used: $ uname ...
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1answer
91 views

What do the terms CC, LD and SHIPPED refer to during the Kernel Source compilation process?

What do the terms CC, LD and SHIPPED refer to during the Kernel Source compilation process? Am I correct to assume that [M] indicates that it is being compiled as a module?
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127 views

What proportion of memory does the Linux kernel use of the installed RAM?

I'm developing a compute cluster and I'm trying to determine the maximum amount of RAM I can give to a single process. On a machine with 16GB of ram, the answer is that I can allocate (and touch) ...
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1answer
38 views

XFRM_SUB_POLICY config in kerne

When testing strongswan performance, we saw that the performance differed by a lot between an ubuntu server and a centos server, with everything else being the same. We noticed that the ...
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1answer
67 views

How do I understand if an USB Ethernet adapter is compatible with a certain kernel version to use it to load kernel/filesystem?

I'm using an old kernel, 2.6.32, and I would like to boot the kernel over TFTP and mount the filesystem over NFS. Mounting the kernel over TFTP is a plus, but mounting the filesystem over NFS is a ...
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27 views

Continuety of driver support in linux kernel

I am an embedded GNU/Linux learner. I understand with the new Kernel, driver support for most added hardware is coming through Device Tree Structure (DTS). But I have found out that there are still ...
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24 views

Find the creator of a task

I would like to find the creator task of an arbitrary task in the Linux kernel. However, I am not sure, if there is a way to do this in general. Normally, you can find the creator of a task via the ...
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1answer
46 views

Install kernel .deb file without using dpkg

I'm running Manjaro (Derived from Arch). I have a .deb file for kernel 4.0. Is it possible to install the kernel from this file, and what are the steps involved? I tried opening the .deb file and ...
2
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1answer
71 views

add key to proc/keys

How do I add a key to a keyring in /proc/keys ? My openembedded Linux does not come with a keyctl command program. And all I can find on google is the programming interface, but I would like to do ...
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1answer
53 views

what if I uninstall all linux kernel images from my system

If I run this: sudo apt-get purge linux-image-* this will definitely remove all linux kernels images from my system. so the question is will I be able to use my system normally until I reboot or ...
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1answer
161 views

How can I edit /proc/net/tcp?

I need to edit 1 line in /proc/net/tcp while the file is also used by the linux kernel for updating other lines of it by the kernel. Background: Each line in /proc/net/tcp represents a TCP socket. ...
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1answer
1k views

Device eth0 does not seem to be present, delaying initialization

I have cloned a fedora and now trying to configure network interfaces. Every time i am adding a new NIC, it starts with number eth3 (rather eth0). i have tried removing and modifying the ...
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125 views

What happened after I upgraded the kernel version?

I have Linux Mint 17.1 Cinnamon version on my notebook HP Compaq 15-h050nl and about 1 month ago I upgraded the Linux Kernels to the current version (3.18.2-031802-generic) from the last version. ...
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centos 7 installation with customized bridge module

I have installed latest Centos 7 x64 edition in my server. I need to modify the linux-bridge module with some customized changes and use it as a default bridge module. Currently I am building centos ...
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1answer
120 views

Getting error virtualbox-guest-modules: requires linux<4.0 on antergos while doing system upgrade

I am running Antergos Linux 64 bit on virtual box. when I try to do full system upgrade I get a error: resolving dependencies... looking for conflicting packages... error: failed to prepare ...
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2answers
129 views

Identify out of tree modules?

I'm attempting to upgrade and test kernel 3.12. What is the most efficient way to identify out-of-tree modules that should be removed before testing? There are a few mentioned (vitualbox, nvidia, ...