Questions tagged [linux-kernel]

The Linux kernel is the operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software.

The Linux kernel is the operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software.

The Linux kernel is released under the GNU General Public License version 2 (GPLv2) (plus some firmware images with various non-free licenses[citation needed]), and is developed by contributors worldwide. Day-to-day development discussions take place on the Linux kernel mailing list.

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Ubuntu 14.04 TCP established hash table entries

A bit of background I am running two servers under high traffic one with ubuntu 12.04 (linux 3.2.0-69-generic) and one with ubuntu 14.04 (linux 3.13.0-52-generic). I am now trying to secure both. They both have very similar hardware resources (same…
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Empty fstab on Debian 7 and up. Possible side effects?

When I was checking a machine set up by our sysadmin team, I encountered an completely empty fstab. In fact it was the default fstab installed by a debootstrap. # UNCONFIGURED FSTAB FOR BASE SYSTEM I was going WTF first, but since the system is…
itsafire
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Hide kernel messages in plymouth

I am running Ubuntu 14.04 server for Kiosk application. The problem is when kiosk is starting , kernel shows some debug messages about stuff like USB port error and such things, and those ugly messages are being displayed over our plymouth splash…
Hasan
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sysctl: cannot stat /proc/sys/kernel/exec-shield: No such file or directory

Enable ExecShield protection - ExecShield is security Linux kernel patch to avoid worms and other problems. After Adding to /etc/sysctl kernel.exec-shield = 1 Getting this error sysctl: cannot stat /proc/sys/kernel/exec-shield: No such file or…
Ashish Karpe
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How can I directly read data from a file in Linux without using the filesystem cache?

I have shared storage which is mounted (read-only) on SERVER1, and mounted (read-write) on SERVER2. SERVER2 is writing data to a file. SERVER1 is reading data from that file. The file poling is <100ms, which is fast, but lets just say it's…
user1955162
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Can I use kernel modules on Amazon HVM/PV instances?

It's a perfectly stupid idea, I know. But I want to test one of my older projects, which includes kernel module (Netfilter extension) on a virtualized cloud-y instance. Will it be possible for me to plug kernel code into Amazon's virtualized (I see…
kagali-san
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Random machine hangs with NFSv4 on CentOS/RHEL 6.5

We have an in-house "compute farm" with about 100 CentOS (free re-distribution of RHEL) 5.7 and 6.5 x86_64 servers. (We are in the process of upgrading all the 5.7 boxes to 6.5.) All these machines do two NFSv4 mounts (with sec=krb5p) to two…
Matt
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AWS fails to resize an RHEL64 instance upon launch

I'm using AWS to boot up a RHEL64 instance but the disk is failing to resize to fit the volume I've selected. Here's the scenario: I Launch a running instance from the Marketplace AMI ami-517eec6b (which is RedHat's approved RHEL64 image), and…
Snowy
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Server crashes because of SMP

My web server is crashing every few days unless I disable SMP with "nosmp" parameter in Grub config. It is not an hardware failure because the problem persists after moving everything to a new machine. Does anyone know which application could make…
Antares
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Can a Linux Kernel be shared between two operating systems?

Quite simple question. I am working on a project to have multiple operating systems (all linux) on the same machine using btrfs subvolumes so that the user can boot to the environment they are comfortable with. Since all of them use the Linux…
flungo
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"error: ‘PATH_MAX’ undeclared" when trying to make menuconfig

I have an OVH cloud VPS with Ubuntu 14.04 64 bit server. I needed linux headers which OVH does not provide by default, so I found some tutorials on how to compile the linux kernel from source using the OVH config files, which should allow for…
JohnRDOrazio
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Windows multicast NLB with Linux clients

I'm (on behalf of a client, anyway) having some troubles with Linux accessing a multicast NLB cluster hosted on Hyper-V (waiting for more information on what version, but I don't think the version is too relevant because this seems a client side…
gac
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The default value for vm.dirty_background_ratio

Wondering why the default value for "vm.dirty_background_ratio" from Linux Server (CentOS and Ubuntu) is set to 40. Is this just a recommendation for safety? Or is there any particular reason why? If the total system memory is over 32Gb, 40% is…
Jaeha Ahn
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linux not replying to an arp request

I am running linux 3.14 on a system with 2 interfaces. on the first interface, i can access our local network. on the second interface, arp packets come in but linux doesn't send out reply. is it possible that the mac address is causing linux to…
mark
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shorewall can'T start: UNTRACKED state requires Raw Table in your kernel and iptables

I'm trying setting up my firewall and installed and configured shorewall. Unfortunately I tried to directly configure iptables first, but this didn't work. When I start shorewall, I get this messages ins /var/log/shorewall-init.log: Processing…
sedrubal
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