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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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Will modules installed by insmod command persist after rebooting?

There is how the book I'm reading describe the insmod utility: The program loads the module code and data into the kernel, which, in turn, performs a function similar to that of ld, in that it links any unresolved symbol in the module to…
apache
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Munin "Available entropy" when using address space layout randomization

Having just configured Munin for statistics logging on my gentoo server (hardened profile), I am noticing that my "Available entropy" is consitently in the 200-300 range. This seems way to low, so I checked it manually using the command $ cat…
Simon Lindgren
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Enabling wireguard log messages with secure boot / kernel lockdown enabled

On fedora 37, I am trying to enable kernel log messages for wireguard by executing this command in a root-shell: echo module wireguard +p > /sys/kernel/debug/dynamic_debug/control Unfortunately, this results in an error: operation not permitted:…
Zulakis
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Why I get "cache" in the output of `ip route get`?

I'm using kernel 5.11.0 and in the ip-route manual [1] it can be read: Starting with Linux kernel version 3.6, there is no routing cache for IPv4 anymore. Hence ip route show cached will never print any entries on systems with this or newer kernel…
mosquetero
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Setting CPU frequency to hardware minimum limit - will it harm the hardware?

I'm running on a Intel Celeron N4120. I can easily set the CPU governor for all 4 cores to powersave using: for n in {0..3} do sudo cpufreq-set -g powersave -c $n done Now, using cpufreq-info I know the hardware limits of my CPU is 800 MHz - 2.60…
q-codes
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how to triage linux disk IO system-wide "hang"

I have a box that is periodically "going out to lunch". Symptoms are anything requiring actual disk IO hang for 30+ seconds, and it appears anything already paged in is unaffected. The problem occurs intermittently, up to a few times an hour),…
some bits flipped
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watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [kswapd4:543]

My Ubuntu 20.04 server has started complaining: [138070.784987] watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [kswapd4:543] [138070.784999] Modules linked in: ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs cpuid rpcsec_gss_krb5 nfsv4 nfs fscache…
Ole Tange
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What is using (kernel) memory?

I know this kind of questions about memory usage have been asked several times, but unfortunately none seem to answer our current problem. We are currently running an AWS EC2 instance with the following specs: t3.medium instance with 4GB RAM and OS:…
mitsos1os
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Why is IPv6 disabled upon reboot even after configuring sysctl.conf?

First of all it cracks me up how many articles are out there to force IPv6 OFF on linux servers. Come on folks, get with the new! :D root@hodor:~# lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux…
Lon Kaut
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What is Synology's RAID Technology based on?

I am curious about Synology's RAID Technology is based on which linux kernel modules. It seems MD+LVM according to its service center but I am not quite sure. Or the RAID function on filesystem is also possible.
codexplorer
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vmalloc allocation failure when scaling LXC containers past 1350 on Proxmox 6.2

I have a server of the following spec: Dual AMD EPYC 7742, 1TB RAM, 8TB SWAP (Round-robin 8xNVME array), 144TB SSD Storage (72 drives over 10 zpools) uname -a Linux host 5.4.44-1-pve #1 SMP PVE 5.4.44-1 (Fri, 12 Jun 2020 08:18:46 +0200) x86_64…
joinsplit
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Debain 10 - Installing kernel 5 from backports

I tried to install kernel 5.x from backports in a frsh installed debian 10 and I failed because I have a 10G NIC: echo deb http://deb.debian.org/debian buster-backports main contrib non-free > /etc/apt/sources.list.d/buster-backports.list apt-get…
Janning
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(105: No buffer space available) while connecting to upstream,

The server is returning 500 error. And in the logs I see many records like (105: No buffer space available) while connecting to upstream Tried to restart server : didn't help. Increased the number of sockets : didn't help. VPS, running Ubuntu…
Alexander P
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Router disappearing from route table (Linux)

I'm running SLES 12 SP3 in a production environment. There are several interfaces configured on two separate networks. Things are working fine for a while(days at a time) and for no apparent reason, 1 or 2 of the gateways will get dropped from the…
jetson23
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How does Linux kernel decide when to free pages allocated via mmap?

I have an application that mmaps a large read-only data structure into memory and reads parts of it. After some time, around 1 GB of physical memory is filled with pages loaded from this data structure. When the amount of free memory on that…
Pavel
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