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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What mean is " pciehp: link training error: status 0x1001 "
Sometime when I use ipmitool to control my HBA power , it will be hang in and dmesg show :
[ 320.891399] pciehp 0000:00:02.0:pcie004: Slot(5-1): Card present
[ 322.091096] pcieport 0000:00:02.0: ...
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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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1
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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 does the mlx5 driver use the IOVA generated by IOMMU as DMA address?
I have enabled IOMMU on the physical machine. I expect the RDMA NIC to use the IOVA allocated by the IOMMU module for DMA after enabling IOMMU. However, in reality, the RDMA NIC does not use the IOVA ...
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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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243
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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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1
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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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Exceed routing limit of 255 on Debian (any Kernel version)
I want to setup more than 255 GRE tunnels between 1 server and about "6000 other servers/aka proxies", method used is:
sudo ip tunnel add gre1 mode gre local 149.5.175.220 remote 5.182.37.41 ...
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167
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changing queue parameter nr_request on NVMe dev
We would like to use NVMes (SAMSUNG MZ1LB1T9HALS-00007) as a cache-tier in a Ceph System (17.2.0). The problem is that the stored data has a lot of small files and if hot-tiering is set to ~70% on the ...
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VMware Host only networks: Hosts not receiving NULL/FIN/XMAS packets using PFsense router
Setup:
2 host-only ints each connected to a separate host on a separate network
PFsense VM routing between 2 networks (implicit accept on both networks, no other rules)
Can receive normal, syn,syn/ack,...
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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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2
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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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2
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193
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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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0
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62
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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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108
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GTP-U configuration in OVS
I'm trying to configure a virtual GTP-U interface in OVS, however when I try the below command (from https://docs.openvswitch.org/en/latest/faq/configuration/):
Q: Does Open vSwitch support GTP-U?
A: ...
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243
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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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Reusing Virtual Network Devices across different customers
I am trying to reuse virtual networks(made of virtual linux network devices) across customers. I am facing issue where we are not able to find if there is any network packet from previous customer is ...
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2
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299
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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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Facing issue with installing Rocky Linux 8.6 on EXSI 6.0
I installed Rocky Linux 8.6 on Vmware EXSI 6.0 after installation when the system is trying to boot after the grub splash screen I am getting an error of Kernel Panic - not syncing: Fatal exception
...
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2
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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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"ALERT! /dev/mapper/vg0-root does not exist. Dropping to a shell!" when compile linux kernel
I compiled linux kernel and got the error seems like initrd can't read file system. I tried both in LVM and non-LVM but none of them work.
With LVM, the error showed:
**ALERT! /dev/mapper/vg0-root ...
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1
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396
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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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Where is my eBPF per-cpu-array data going?
I have a test case similar to code in https://github.com/xdp-project/xdp-tutorial/ which
maintains a statistic map in a per-cpu array, and user-space code
which displays the statistics periodically.
...
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2
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How dangerous might it be - and what performance gains may be had - by turning vulnerability mitigations off on non-Internet facing servers?
When a virtual machine Linux host server is non-Internet facing and is used exclusively on a LAN and is using a relatively well tested distribution like Proxmox, how dangerous would it be to turn off ...
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How to get the kernel not to treat a packet injected through tun/tap as a 'martian'
I have a new test case for https://github.com/xdp-project/bpf-examples here
https://github.com/tjcw/bpf-examples/tree/tjcw-integration-0.3/AF_XDP-filter
. It is for filtering flows; the idea is to ...
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Is it possible to use DPDK in a server with single NIC?
I have a a server with single NIC which has 4 pci ports. I already tried DPDK binding so before binding "dpdk-devbind.py -s" returns this :
Network devices using kernel driver
0000:01:00.0 '...
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Is it possible to disable and re-enable on-board PCI devices in Linux?
So as the title suggests, Is there a way I can disable and re-enable PCI devices or on-board devices on Linux using Terminal like the disable and enable device functions in Windows' Device Manager. I ...
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How to trace NAT traffic (port-forwarding) from guest VM back to host
I have a host and guest Virtual-Machine (VirtualBox) with NAT Networking with the following network interfaces.
How to trace traffic from local IP 10.0.2.15 i.e. guest's IP back to Host ?
Host
Ubuntu
...
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How to pass driver parameters via dkms?
I am trying build/install a driver via dkms. I have successfully started the driver with its default parameters but not sure how to add optional params?
For example to install the driver using insmod ...
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There is no dir "/sys/devices/pci0000:00/0000:00:02.0/mdev_supported_types" with 5.19.0-23-generic
I've an issue with 5.19.0-23-generic #24-Ubuntu SMP, — there is no /sys/devices/pci0000:00/0000:00:02.0/mdev_supported_types dir.
uname -a
Linux hp1 5.19.0-23-generic #24-Ubuntu SMP PREEMPT_DYNAMIC ...
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Using reserved / deprecated IPv6 ranges on older linux kernels
I have an old Synology NAS with kernel 2.6.32.12.
And I use the Yggdrasil network, which uses the deprecated range 0200::/7 for addressing.
About the range 0200::/7:
http://www.iana.org/assignments/...
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Message printing after I apt-get install or needrestart about services, containers, user sessions and VMs
I've just put Ubuntu 22.04 on my server, and when I execute apt-get install x(where x a package I want to download) or needrestart, I get this message that I haven't found an explanation for.
Running ...
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modprobe: FATAL: Module nf_conntrack_ipv4 not found in directory
TASK [kubernetes/node : Modprobe nf_conntrack_ipv4] *************************************************************************************
fatal: [node1]: FAILED! => {"changed": false, &...
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Debian reboot suggested after kernel update since Bullseye
So I've been using Stretch as a production server for a small academic research office.
Had a nice ~500 or so days of uptime, and I kept it up to date as updates rolled.
This summer, Stretch was ...
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Unknown kernel command line parameters "BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo.x86_64", will be passed to user space
On CentOS 7, after upgrading the kernel to version 5.18.11, I observed the below message in /var/log/messages:
Unknown kernel command line parameters "BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo....
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Kernel version for MySQL 8
I have a server with kernel version 3.10. This seems to be a quite old kernel (though patches are backported). Is there any reason to force an update to kernel 5.x?
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825
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Symlink doesn't work when pointing to file on different mount point using relative path
On one of my machine, cd /var/lock fails despite that /var/lock is a symlink to an existing directory ../run/lock.
After further investigation, I found that any symlink pointing to another mount point ...
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0
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278
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On Linux ZFS Server - What is eating my memory?
Our monitoring tool regularly reports low memory for one of our servers running ZFS.
# free -g
total used free shared buff/cache available
Mem: 125 ...
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204
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Qemu debug linux kernel, can not load modules
Recently, I'm try to compile linux kernel and use gdb debug, follow :debug kernel ;linux kernel debug;
And I found my lx-symbols gdb cmd can not load other modules and symbols, only output: load ...
