Questions tagged [kernel]

In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software components).

In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software components).

Usually as a basic component of an operating system, a kernel can provide the lowest-level abstraction layer for the resources (especially processors and I/O devices) that application software must control to perform its function. It typically makes these facilities available to application processes through inter-process communication mechanisms and system calls.

Operating system tasks are done differently by different kernels, depending on their design and implementation. While monolithic kernels execute all the operating system code in the same address space to increase the performance of the system, microkernels run most of the operating system services in user space as servers, aiming to improve maintainability and modularity of the operating system.

Source: wikipedia

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How to find out the reason(s) why the network interface is dropping packets?

Is there a way on Linux to get statistics about the various reasons packets were dropped? On all network interfaces (openSUSE 12.3) on several servers, ifconfig and netstat -i are reporting dropped packets at the reception. When I do a tcpdump, the…
Huygens
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Kernel stack trace to source code lines

Given a kernel stack trace as below, how do you determine the specific line of code where the issue occurred? kernel: [] __link_path_walk+0x173/0xfb9 kernel: [] mntput_no_expire+0x19/0x89 kernel: …
tylerl
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Is it important to reboot Linux after a kernel update?

I have a few production Fedora and Debian webservers that host our sites as well as user shell accounts (used for git vcs work, some screen+irssi sessions, etc). Occasionally a new kernel update will come down the pipeline in yum/apt-get, and I was…
lfaraone
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can high load cause server hang and error "blocked for more than 120 seconds"?

Currently running a few VM's and 'baremetal' servers. Java is running on high - over 400%+ at times. Randomly the server hangs with the error in the console "java - blocked for more than 120 seconds" - kjournald, etc. I cannot get a dmesg output…
Tee
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GRUB "Some modules may be missing from core image" warning

one HDD crashed from my RAID and I added a new HDD. Now I wanted to install GRUB to the new HDD: with grub-install /dev/sdb. I get these warnings: Installing for i386-pc platform. grub-install: warning: Couldn't find physical volume `(null)'. Some…
pythonimus
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How to fix "BUG: soft lockup - CPU#0 stuck for 17163091968s"?

UPDATE: I updated the title of the message, because I've recently seen more of these problems with this exact time amount of 17163091968s. This should help people investigating the symptoms to find this page. See my (self-)accepted answer below. I…
tuomassalo
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Converting an EC2 AMI to vmdk image

I've come quite close to getting Amazon Linux to boot inside VirtualBox, thanks to this answer and these websites. A quick overview of the steps I've taken: Launch EC2 instance with Amazon Linux 2011.09 64-bit AMI dd the contents of the EBS volume…
Reed G. Law
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What is the largest hardware clock update the Linux kernel "11-minute mode" can make?

When certain time-related programs (like ntpd) are running on a Linux system, the kernel will switch into so-called "eleven minute mode" (see the hwclock man page) whereby it will automatically update the hardware clock from the system clock every…
QuantumMechanic
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Can I delete folders in /lib/modules/ after calling "apt-get purge"

I've already call apt-get purge to uninstall the old kernels. But some error occured during the purge that caused the folders to be left behind. It said the folder was not empty so it couldn't delete. To free up disk space can I manually delete…
Dalton Tan
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How to disable perf subsystem in Linux kernel?

I'm running some benchmarks. My benchmark runner monitors the dmesg buffer between experiments, looking for anything which could impact performance. Today it threw this up: [2015-08-17 10:20:14 WARNING] dmesg seems to have changed! Diff…
Edd Barrett
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Taskset not working over a range of cores in isolcpus

To preface I'm using Debian Wheezy with kernel 3.2 on an AMD64 chipset. My machine has two Xeon E5-2690 cores. I set up the boot parameters so that all the cores on one CPU are dedicated to a single process. To do this I've set…
user79126
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Prevent the console from clearing the screen?

When booting into Linux, there are sometimes one or two lines that get quickly cleared. I think that some of them don't even appear in dmesg. If nothing else, I want to suppress the clear before the "login:" prompt. Is there a kernel command or…
Paul Hoffman
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Disabling rp_filter on one interface

I have an Ubuntu 16.04 Server which is acting as a router with multiple (VLAN) interfaces. By default, rp_filter (reverse path filtering) is enabled for all interfaces. I want to keep it that way, but make an exception for exactly one interface.…
Cybran
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is ksplice production ready?

I would be interested to hear the serverfault community's experiences with Ksplice in production. Quick blurb from wikipedia: Ksplice is a free and open source extension of the Linux kernel which allows system administrators to apply security…
faultyserver
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Why are connections in FIN_WAIT2 state not closed by the Linux kernel?

I have an issue in a long-lived process called kube-proxy being part of Kubernetes. The problem is that from time to time a connection is left in FIN_WAIT2 state. $ sudo netstat -tpn | grep FIN_WAIT2 tcp6 0 0 10.244.0.1:33132 …
Adam Romanek
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