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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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OOM kills a process while there is still a lot of available memory

I am aware that there are many threads like this one, but none of them actually give a methodology on how to read an OOM message. I have a db that is being monitored through NRPE for available memory, using a shell script check that calls free -m…
user3081519
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how to decently configure net.ipv4.neigh.default.gc_thresh_n

We recently had a storm of kernel: neighbour: arp_cache: neighbor table overflow! errors on some nodes of our kubernetes cluster. After research we've figured out that we needed to bump our servers net.ipv4.neigh.default.gc_thresh{1,2,3} to match…
vinni_f
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FATAL: modpost: GPL-incompatible Module. Uses GPL-only symbol 'sme_active'

Full Error Message FATAL: modpost: GPL-incompatible module celerity16fcmp.ko uses GPL-only symbol 'sme_active' CentOS 7.6 machine unable to install ATTO Fibre Channel drivers due to GPL error in kernel. I know what needs to be done per ATTO Tech…
Aren Tahmasian
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Are these errors in dmesg (related to PCI/NVME drive) anything to be concerned about?

Anyone know what this error below (dmesg output) indicates? I'm getting it when periodically writing to an Intel NVME drive (attached to a PCI card) under Linux. Not sure if "no further action" means I should just ignore it or if the PCI card is…
Server Fault
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iptables: Rate too fast Error

I want to set hard limit for incoming UDP packets on my Linux machine which is inside 10 Gigabit LAN. Following command works fine /sbin/iptables -A UDP-LIMIT -m limit --limit 10000/s --limit-burst 500 -j RETURN But when I try to increase limit…
techiek7
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IPv4 identification field manipulation in linux

When Don't Fragment flag is set, IPv4 RFC allows set Identification filed to 0x0000. I got a peer which is behind firewall that brakes RFC and block any IPv4 packets with such 0x0000 ID field. My "modern" 4.4.0 linux kernel generates packets with ID…
luzik
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Are Kerberos service tickets cached by mount.cifs or kernel?

When mounting a CIFS share using krbr5i and destroying my Kerberos tickets with kdestroy afterwards its still possible to mount other shares on the same server. How is this possible? Doesn't mount.cifs have to send the service ticket to the sharing…
sahisb
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What are the parameters in iostat

I used iostat and trying to understand the iostat output using this link : https://linoxide.com/linux-command/linux-iostat-command/ but It is not clearly explained. PF the output at different times from 18:00:00 to 18:45:00 : We got the delay in…
Harry
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linux (ubuntu 17.10) fan stopped working

At some point recently, my fan stopped working. I've confirmed it's not the hardware, because in the bios I can start and stop the fan. This is an ubuntu 17.10 desktop host. I noticed that lm-sensors wasn't noticing the fan. With a bit of…
jma
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Kernel Panic on Guest-VM (Debian 9)

I have two servers running with Debian Jessie Kernel 3.16.0-5-amd64. Both servers have the exact same configuration, only hardware differs. I use KVM as hypervisor together with QEMU on both servers. When i try to install Debian 9 (Kernel 4..) on a…
robusto
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Fibre Optic port moving to 1000Mb/s eventhough it is not in the supported link mode

In my Fibre Optic device (Linux 2.6.27, LXT971A PHY Transceiver), connection to the port is lost intermittently. While debugging with ETHtool, the following observation was observed: Settings for eth0: Supported ports: [ TP MII ] Supported link…
karthikkumar
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Kernel panic - not syncing Attempted to kill init after mount

I have a VPS running Debian 8 at OVH. Recently I couldn't connect to the SSH because I received the message: "access denied". So I decided to reset the root password. I followed OVH indications in order to reset the root password: I connected to…
Pascut
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How To Tune Apache prefork mpm values on linux Server

Currently I am on Apache/2.4.23 version and I am running multiple virtual host sites on my webserver behind an ELB. I have 4 instances under my ELB each with 8GB of total RAM. On these webservers I don't see any mpm directives set in my httpd.conf…
MichealMills
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Ubuntu quota format not supported in kernel

I was trying implement disk user and group quotas at Google Compute Engine with Ubuntu 16.04 LTS, but till now i'm unsuccessful. Quota allows you to specify limits on two aspects of disk storage: the number of inodes a user or a group of users may…
Clemente Nogueira
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Crash utility exit with error in Rhel6.6

Crash utility fails with below error. crash /usr/lib/debug/lib/modules/2.6.32-504.el6.x86_64.debug/vmlinux vmcore crash 6.1.0-5.el6 Copyright (C) 2002-2012 Red Hat, Inc. Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation Copyright (C) 1999-2006 …
Paul Jany Godwin
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