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.
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OOM killing programs when used memory is at 30%
I am getting a bit crazy about this one: I am getting quite often processes killed by the kernel because of OOM. I see that free reports 14 GB used out of 14 GB, but when I add up the RSS of all the ...
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Is it possible to run Docker on a hypervisor type 1?
Is it possible to run Docker bare metal on a type 1 hypervisor such as VMware and Hyper-V?
Docker uses that same kernel as the host. So if the hypervisor is based on linux, does that work? Is there ...
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I/O errors during BLKDISCARD on Linux Dell R720 with SAS Seagate Nytro
I have a Dell R720 with PERC H310 Mini (LSI 2008 MegaRAID) controller which I have just loaded with 4 new Seagate Nytro XS1600LE70045 1.6TB SSD, configured as individual disks for Linux software raid. ...
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Is it safe to mount same btrfs subvolume multiple times at same time?
I know that it is safe to mount multiple volumes from the same btrfs volume at the same time. But what about the same subvolume? The subvolume would be mounted from the same Linux kernel instance. ...
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TCP_NODELAY for All current sockets in linux
i want lowest latency network with tcp_nodelay., in windows OS we can easily enable TCP_NODELAY through registry of windows. i searched on the red hat website and another website but up to now, my ...
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Remove old kernels with security implications / vulnerabilities
Some scanning tools (Qualsys, Sentinel, etc) detect installed old kernels and will report them as problems if those kernel versions have vulnerabilities. Is there a way to remove them if they have ...
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MariaDB io_uring_queue_init() failed with errno 1 with kernel version 6.2.0-1018
I am running MariaDB using the official docker hub image: mariadb:lts
(this is MariaDB 10.11.6-MariaDB-1:10.11.6+maria~ubu2204 source revision fecd78b83785d5ae96f2c6ff340375be803cd299)
When the ...
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Why do we need "never" for transparent huge pages?
Transparent huge pages (THP) can be always, madvise and never.
I see that most database tutorials suggest using never for valid reasons. However, why do we need the never option at all if programs can ...
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meminfo doesn't include memory allocated by page_allocator
I found that the meminfo doesn't show the memory usage which is directly allocated by the page allocator (fn:allocate_pages)
file:///proc/meminfo
MemTotal: 2039496 kB
MemFree: 108684 ...
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Adjust Logging Level for the OOM Killer
Is there a way to configure Linux so that the OOM killer will report/post only which process is killed, but not dump the entire machine state with it?
The reason I ask that is, that on our production ...
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Unable to ping the vm running with ebpf program
I am using an eBPF program which counts the number of packets received on its interface on my destination vm.
At first I can able to ping the vm running with eBPF program that is destination from the ...
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Why are compact_stall increasing on a system with Transparent Hugetable defrag set to 'defer'?
We're running a reverse proxying application within docker that is very
network intensive. Dockerd is occasionally allocating memory using
madv_hugepage, and we've observed this sometimes causes ...
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Linux Kernel Module loading in Docker container - Runaway Usage
When starting a docker container on an Amazon Linux 2 instance, I load a kernel module. I first unload the module, and load it again so that if the kernel module is updated, the newest version will be ...
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Debian - Wireguard Forces Real Time Kernel
I've a system running Debian 12 and while trying to install Wireguard I noticed it would pull a different kernel:
root@iotgateway:~# apt install wireguard --no-install-recommends
Reading package lists....
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How to change the batch size of pcp in linux kernel?
I increased the pcp->high via echo 8 > /proc/sys/vm/percpu_pagelist_fraction command, but the pcp->batch value still remains at 63.
vm stats threshold: 125
cpu: 383
count: 103931
...
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RHEL9.2 complains about missing /lib/modules/5.14.0-284.25.1.el9_2.x86_64 when rebuilding initramfs
The kernel on one of our RHEL9.2 servers was recently upgraded to 6.2.8 in preparation for a software upgrade but due to complications, we've had to revert back to 5.14.0-284.25.1.el9_2.x86_64.
I've ...
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Raising priority of network interface interrupts on Ubuntu 22 low latency kernel 5.15
I am running Ubuntu 18 on several servers with the low latency kernel.
Previously I have used chrt to raise the priority of interrupt threads for the interrupts related to a specific network interface....
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I want to make Linux Kernel Source an RPM file
I am currently using Rocky Linux 8.7.
The current kernel version is "4.18.0-425.13.1.el8_7.x86_64".
I want to upgrade kernel through RPM, not source compile. In the kernel compile step, use ...
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Re-compressing XZ kernel module?
I have a kernel module produced by kernel option CONFIG_MODULE_COMPRESS_XZ. When I manually decompress the file with unxz and re-compress with xz, the new .ko.xz file differs from the original .ko.xz ...
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Ethernet connection is dropped when restarting openibd ( Infiniband ) service
I have a multiple servers with Ethernet controller on board and InfiniBand controller installed in a PCI slot.
The problem is when im restarting openibd.service which should control only the ...
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How to make IpTable Rules immutable in linux
I work on Linux and want to add rules to iptable. I want these rules to be immutable anyway (either changed or deleted). What should I do? Note that for me the rules that are running and kept in ...
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rp_filter kernel setting precedence
When rp_filter kernel setting is configured with different boolean, which takes precedence? all.rp_filter or interface.rp_filter?
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
...
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Many linux process falling into 'D' status, server got stuck
I am running a high performance application on Centos 7.4 op system 3.10 with RT kernel. Sometimes a few process falling into 'D' status(uninterruptible), such as systemd、runc init、umount. The stack ...
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How to get rid of “Duplicate IMA measurements will not be recorded in the IMA log.”?
In the journal of my Debian 12 kernel linux-image-6.1.0-10-amd64 version 6.1.37-1 I discovered the following lines:
…
… hostname systemd[1]: Starting systemd-journald.service - Journal Service …
… ...
user1030416
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failed to create fsnotify watcher: too many open files
I received this error while trying to tail the log of a Kubernetes pod.
failed to create fsnotify watcher: too many open files
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Centos show me "Cannot find a valid baseurl for repo: base/7/x86_64"
Hi, i have a issue, when i type in Centos 7 "yum update" show me next error
Loading mirror speeds from cached hostfile
One of the configured repositories failed (Unknown),
and yum doesn't ...
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375
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How does GRE interface route packet to remote endpoint
I have the following topology which I configured to run a GRE tunnel between my Desktop and the wireless router.
On the PC:
ip link add l2gre0 type gretap remote 192.168.0.103 local 192.168.0.10
On ...
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debian update fails on buildine "new" kernel
my current version
$ cat /etc/*elease*
PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"
NAME="Debian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
...
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Updating Centos 8.0 to Centos 8.3
I need your expert help on how can I update Centos 8.0 to Centos 8.3. I have installed Centos 8.0 using the standard option without GUI. It's a requirement at work. Please help
Thanks & regards,
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Cannot downgrade linux-image-amd64
Some time ago, I wanted to try the 5.10.127-2~bpo10+1 kernel on Debian
10 Buster system.
However, that kernel was not maintained nor patched by Debian any longer.
Now, new 4.19.x kernels no longer ...
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Traffic Control - Searching clsact filters by parent ID
According to net, sched: add clsact qdisc you add filter on ingress and egress after adding clsact,e.g.
➜ tc qdisc add dev foo clsact
➜ tc qdisc show dev foo
➜ tc filter add dev foo ingress bpf ...
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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, ...
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Kernel reboot without log during starting the crash kernel
I am testing crash kernel image feature with arm64 device, kernel version is linux-5.4, now i am trigger kernel crash via "echo c > /proc/sysrq-trigger", then kernel would trigger null-...
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May I ask during runtime how to check the some kernel command line parameters which not set in the grub but have a default value?
I notice there are some kernel command line parameters like below, which from Manual:
audit= [KNL] Enable the audit sub-system
Format: { "0" | "...
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How do I fix amdgpu and amdgpu-dkms packages not installing?
I'm trying to install the amdgpu package and it throws a bunch of errors:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages were ...
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590
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Cannot boot on Arch Linux after modifying kernel parameters with GRUB
Looking for a way to set my backlights on my laptop running Arch Linux (and Windows on a dual boot), I edited the /etc/default/grub file to change a kernel parameter. Here is what I changed:
# before ...
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How to find the cause of a server kernel panic?
Our high-load server is in kernel panic. How can we identify the cause and correct it?
It is a Dell PowerEdge R940 with 256GB ram and 20TB disk array with the root in a SSD disk.
Linux CentOs 7 system....
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Why do some servers have /etc/sysconfig/kernel and others do not?
I spent some time looking into this and couldn't figure out why there are servers with and without /etc/sysconfig/kernel.
What's particularly interesting is that we have some servers with the same ...
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Routing issue on Debian 11 VM
I updated my OPnsense "router/gateway" to 23.1 a few days ago, and now I am experiencing an issue with one of my machines. I have one machine with OPnsense installed that acts as a basic NAT ...
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Can a Linux web server which hasn't been restarted for years be secure?
The content of /proc/uptime reports:
48973211.37 1627573879.70
48973211 seconds mean the server is up for 567 days without a restart.
Since then many serious security fixes have been applied to the ...
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How to debug Linux server reboots?
I have a Debian 10 server that keeps rebooting. journalctl offers possibility to list last boots:
journalctl --list-boots
-6 1ee519dc5bc24e88af75cc609ee32093 Mon 2023-02-06 21:02:02 UTC—Sun 2023-02-12 ...
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ICMP Echo requests initiated from an interface inside VRF don't get ICMP echo replies
I have this setup, which is basically a linux server with one physical interface connected to another device. On this physical interface there is 2 VLANs, 100 and 200. In VLAN100 there is an IP ...
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Injected packets using libPCAP library is not seen from python socket sniffer and netcat
I am using libpcap to transmit packets between two VETH pairs {veth1, veth1peer} and {veth2, veth2peer} and using each others peer to inject packets upwards to veth1 or veth2 and disabled "rp-...
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No irq handler for vector - randomly starting after time
I don't know where to start, so I give some basic information about my system and my observation.
I'm having a Fedora 37 Linux server at home. After some uptime (happens after 3-5 days after booting), ...
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Set number of threads when auto compiling kernel
I use Ubuntu as main operating system.
I have found that when a new kernel is included in a system upgrade, during the upgrade, certain kernel-related items are compiled (kernel modules?).
During this ...
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Can't load new modules/driver due to "Exec format error" / "Skipping invalid relocation target"
I'm trying to update the driver for our Intel C62x Chipset QuickAssist Technology add-on card, but getting the mentioned errors when I try to load the modules. I haven't done this in a while, but I ...
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Is there any hardware requirements for Linux kTLS in nginx?
I've followed closely the manual on NGINX blog. This works flawlessly on my machine, with an AMD Ryzen PRO 4750G. The output for a 5GB file using curl on https://localhost is twice as fast with kTLS, ...
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how to delete a file by a inode in linux kernel
I got the inode of a file in linux kernel, I want to delete the file by the inode.
Do I need to unlink every dentry of the inode? or do I need to unlink any dentry?
Which locks should I use to protect ...
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181
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Linux process scheduling by user?
It seems Linux schedules process execution independently of the user of the process. So, if one user is running 100 processes and another user is running 1 process, in average, the first one will get ...
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Debian 11 : Can't add squashfs to /proc/filesystems
I'm trying to fix an issue with snap I'm having :
root@puppeteer:~# snap install core
error: system does not fully support snapd: cannot mount squashfs image using "squashfs": mount:
/...
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