Questions tagged [linux-kernel]
This tag is for questions about the internals of the Linux kernel itself - particularly about use or configuration of kernel modules or drivers.
487
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Cannot create Security Association in CentOS 7.4 using Setkey
I've been asked to migrate from CentOS 6.8 to 7.4 on all of our Linux devices. I'm running into an issue with loading Security Associations into the Linux kernel. I'm using ipsec-tools' ...
2
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1
answer
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How to Turn Off KPTI to Improve Performance in Fedora
Following the outbreak of KPTI news, I recently updated my kernel to 4.14.11-300. In addition to a quite sufficient RAM (8 GB) and fast IO (SSD disk), I have started to feel remarkable slowdown in my ...
0
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1
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Dynamic or virtual file content, similar to /sys/*
Imagine you wanted a file - for example /etc/hosts - but every time the file was read, rather than reading it from the filesystem, its contents were the output of an application - for example a script ...
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0
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Slow command execution time in linux
We experience some slow simple command execution time in Linux, possibly related to procfs slowness.
Like simple uptime command can take few seconds to execute.
Here are the inputs:
Platform: AWS
...
0
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1
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660
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Does kernel compiling depends on DTS files
I am trying to build a custom Linux kernel.
However I don't understand whether compilation is affected by DTS files under "arch/<...>/boot/dts" or it's only up to the bootloader to pass parameters (...
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0
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How to understand this crash dump
This a sample crash dump I have from the unit. Could anyone help me in understanding what these details mean?
Example: [<c406dde4>] (sys_init_module+0x0/0x1878) from [<c400dd00>] (...
35
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7
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VirtualBox Ubuntu Guest Additions not installing : modprobe vboxsf failed
I just installed this software off virtual box, i downloaded the ISO off the official ubuntu website, was the lastest LTS.
I attempted to install Guest Additions using the 'Insert Guest Additions CD ...
0
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1
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361
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Configure built-in modules in cross-compiled linux
I'm in the beginning stages of using a cross compiler (ELDK) to build an embedded Linux system from the kernel source. The Kernel is built successfully with make ARCH=powerpc CROSS_COMPILE=powerpc-...
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1
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GRUB doesn't show all kernels
I installed 16.04 over 14.04.
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial
The problem is that old ...
1
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0
answers
370
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No TTY Terminal after CENTOS Kernel Upgrade and reboot
have a VPS and recently I installed a new kernel
yum history info
Loaded plugins: fastestmirror
Transaction ID : 17
Begin time : Wed Sep 13 18:52:31 2017
Begin rpmdb : 326:...
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0
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USB 3 hard drive and card not working in super-speed mode
So, I recently added a USB3 card to my computer, and I thought everything was good, Linux detected it, though weirdly (or not?) it comes up as 2 hubs
[ 2.086988] xhci_hcd 0000:07:00.0: xHCI Host ...
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2
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Enable serial system console in runtime
There is Linux kernel boot option to enable system console, the console=, for example, console=ttyS0,115200 or console=ttyS0,115200n8
http://www.linuxtopia.org/online_books/linux_kernel/...
2
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2
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5k
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Forcing Ping to Egress When Destination Interface is Local (Debian)
I am running a Debian-based Linux container under Proxmox 4.4. This host has five network interfaces (though only two come into play in the problem I'm having).
While I am shelled into this host, I ...
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4
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Is there any Linux command that I can use to show all the network interfaces except ifconfig
I have to set up a network connection on a Arch Linux install (in Virtualbox) and I need to know what network interfaces I’m using. How can I do this without using ifconfig?
0
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1
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Ubuntu 16.04 hanging VPS server
I have a weird issue with a VPS server I am using for a personal project.
The server started hanging at 10:40 yesterday
The last line from /var/log/syslog before hanging was:
^@^@^@^@^@^@^@^@^@^@^@^@...
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1
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309
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What is the hardware source of Kernel Clock?
According to docs of my South Bridge (ICH9M) it has 4 HPET. How should I found interrupt line, from which System Clock (aka Kernel Clock, Software Clock) is derived?
Seems that it is LOC, but which ...
0
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1
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Where to report issues about "genkernel all" not selecting reasonable defaults?
genkernel states that bugs ought not to be reported against genkernel after a failure like
drivers/scsi/aha1542.c: In function ‘aha1542_interrupt’:
drivers/scsi/aha1542.c:306:3: error: implicit ...
0
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0
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3k
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ubuntu doesn't treat touchscreen input as touch (just left click)
I have a ThinkPad X230T with multitouch-screen, and Ubuntu treats multitouch inputs as just 'clicks'.
Here's my xinputs outout:
⎡ Virtual core pointer id=2 [master pointer (...
0
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2
answers
222
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Creating a Linux installation on external SSD with both 32 and 64 bit boot options
So, my old 60G SSD now lives in an external USB enclosure. I want to install Linux in it, but I want to have the option to run on older hardware if necessary, so I would like to have both 32 and 64-...
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1
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UNMET DEPENDENCIES in parrot 3.6?
i tried some solutions from the web to solve but of no vain.
please help how i can solve the issue.
sudo apt-get upgrade
[sudo] password for harry:
Reading package lists... Done
Building dependency ...
2
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2
answers
2k
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Is it possible to run a process in chroot with virtual /proc filesystem under Linux?
I need to run a process in a chroot with a virtual /proc filesystem, so the process is unable to get access to other processes running on the same host. The process must be run under root and have ...
21
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4
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How to view all boot messages in Linux after booting?
Relevant questions are:
Where Linux places the messages of boot?
Name of log file where boot process is logged
However, these do not answer this question. This question is concerned with how all ...
2
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1
answer
5k
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Latest version of parrot security os?
I recently updated my parrot security os and it got upgraded to version 3.5 cyberGalleon. But in the parrot website downloads the latest version is 3.4.1. is the 3.5 cyberGalleon with kernel 4.9.0 ...
0
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1
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Where is the source code for the classic init system?
I know that systemd and SysVinit have their own projects and are developed independent of the Linux kernel.
But what about the classic init system? where its source code located? is it part of the ...
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0
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3k
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Kworker thread has high CPU usage
I have a kworker thread with high cpu usage, which is causing my touchscreen to be very lag-y and unresponsive.
Running a beaglebone with Debian.
uname -r
4.1.15-ti-rt-r43
pid user pr ni ...
0
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1
answer
422
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How can I safely delete the old kernel version from the /boot partition on Ubuntu?
I am not so into Linux and I have the following problem related to the fact that my /boot partition seems to be full and it seems to cause a problem trying to install a program.
I am using Ubuntu ...
0
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2
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427
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Specific kernel version needed by elrepo on CentOS5
I can not install elrepo in an updated CentOS 5 system.
This is the error we get when we tried to install it:
[root@static ~]# rpm -Uvh http://www.elrepo.org/elrepo-release-5-5.el5.elrepo.noarch.rpm
...
2
votes
2
answers
7k
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Fuse file system with “default permission” option
I am new to fuse. I have mounted fuse by the following command.
/home/bin/fusexmp /mnt/fuse -o default_permissions -o allow_other -o nonempty -o hard_remove -d
Now If I login as "test" user and ...
0
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1
answer
994
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Linux recovery mode graphics state Versus the normal graphics state
What does booting to recovery mode then selecting resume normal boot do to the systems graphics? (on linux distributions like Debian)
I'd like to know things like:
What makes this state "safe". :...
4
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1
answer
5k
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Linux kernel make keeps overwriting my .config /dropping changes
I’m trying to build a custom ARM kernel on a BeagleBone black wireless. I’m using this kernel as a start
I copied the current .config file (make localmodconfig) and edited it manually to add support ...
12
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1
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5k
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How can I prevent the kernel from limiting TX power as advertised by AP
I am connecting to eduroam over a distance of about 150m using an external 23dBm Antenna and an Ubiquiti SR71-E with an Atheros AR9285 chip. My system is Debian Jessie server - so the connection is ...
0
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1
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691
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Unable to enable zswap on digitalocean ubuntu 16.04
I'm trying to enable zswap on my digitalocean Ubuntu 16.04 droplet without any luck.
I tried to apend zswap.enabled=1 to grub's GRUB_CMD_LINUX_DEFAULT and to GRUB_CMD_LINUX and after that run update-...
2
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0
answers
1k
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How to reduce unmovable and and unevictable pages in linux
We have BBB based custom board and it has 256MB RAM and 4GB of eMMC,
We are seeing fragmentation issue on it.
And as a part of analysis I wanted understand, what are unmovable( from /proc/pagetypeinfo)...
1
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0
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199
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Linux menuconfig failed
When I configure linux, I come across the following error:
[linux-devkit]:/opt/ti-processor-sdk-linux-am335x-evm-03.00.00.04/board-support/linux-4.4.12+gitAUTOINC+3639bea54a-g3639bea54a> make ...
0
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1
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1k
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Odd behaviour with Unevictable cache (Linux kernel)
I'm seeing a behaviour I cannot explain on my embedded Linux target (initramfs and no swapping).
As there is no swapping, I would expect anything in /tmp (tmpfs) to be flagged unevictable. Instead, I'...
1
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0
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33
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What is the suggested version of oprofile on Linux kernel 3.4?
I want to use the oprofile tool on Linux kernel version 3.4. If I understand correctly, the latest oprofile version is 1.1.0. Is this correct?
In one of the articles I saw, 0.9x versions of oprofile ...
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0
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How do I update my kernel
So I have this kernel source and I need to update the selinux version, in order to make it support android 6.0 the last thing it supported was 4.4, how do I do that? https://github.com/Packmaan7144/...
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1
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What means this code? [closed]
I cant understand .type and .func in this code.
static struct packet_type ip_packet_type __read_mostly = {
.type = cpu_to_be16(ETH_P_IP),
.func = ip_rcv,};
This is referenced in:
net/ipv4/af_inet....
0
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1
answer
156
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What is the path of ip_input.c?
The ip_rcv funcion defined in the ip_input.c
file, is responsible for delivering the datagrams to a higher
layer protocol or forwarding it to another host. It consists
of functions and netfilter hooks ...
0
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0
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33
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Installation of VB Guest Additons without GCC for many identical RHEL Linux systems
I have a number of nearly identically configured RHEL systems that need to have the VirtualBox Guest Additions installed. Unfortunately, the installation requires the addition of basically the ...
2
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0
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1k
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Strongswan enable ESP packets hardware acceleration
My Linux kernel already support CESA hardware acceleration, and openssl can use this feature:
# openssl speed -evp des3 -elapsed
# cat /proc/interrupts | grep cesa
51: 464810 GIC cesa0
...
0
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0
answers
3k
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Disconnect and close serial port from console so I can use it in my application
Ubuntu 16.04
I need /dev/ttyS0 (serial port) for use in my application.
Command:
~$ dmesg | grep tty
Response with:
[ 0.000000] console [tty0] enabled
[ 0.691609] 00:05: ttyS0 at I/O ...
0
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1
answer
88
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Newest 4.4 kernal not running after updates?
I was farting around with dpkg on my recently re-installed system, looking for a way to see which packages took up the most space (which had been an issue previously) and discovered the following:
$ ...
0
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0
answers
529
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Why would a linux system mount partitions from fstab with one kernel config, but not another?
I have a linux ROM image made by Buildroot with BusyBox init and eudev. The image has an /etc/fstab, which mounts /dev/mmcblk0p1 at /boot, and /dev/mmcblk0p2 at /mnt/var.rw (the upper filesystem for /...
32
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1
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65k
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Enable user namespaces in Debian kernel
I'm trying to figure out how to enable user namespaces capability in my kernel (I think CAP_SYS_USER_NS). I'm using Debian Stretch, kernel 4.6.0-1-amd64.
My assumption is there is a way to turn on ...
1
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0
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673
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What is the minimum amount of RAM required to run Linux Kernel in ARM cortex-a5?
I want to know what is the minimum amount of RAM required to run Linux Kernel (4.6) in ARM cortex-a5.
Now I am using 32MB PSRAM but whenever I am loading vmlinux (elf format) through debugger to ...
0
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1
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182
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Is Kali Linux 2 broken?
This might be just on my part but I really doubt that. I'm running it in persistence from USB, the most notable problems come when trying to login as root, can't it just acknowledges test and even the ...
1
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0
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693
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Kernel panic not syncing attempting to kill init
We have a Citrix Xenserver 6.2 install. Today we had an incident where power to the server was suddenly cut off from the server. It had been running for quite some time without issue. It has quite a ...
3
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2
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2k
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Which is the user‑space command for resuming from hibernation?
During a long time, I used
echo disk > /sys/power/state
In order to hibernate to/dev/sda10and I was using the initrd of my Debian distribution to resume.
But recently, I switched to a raid ...
1
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2
answers
2k
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Which address space is used in system calls? physical? or virtual?
Explanation
There’s two kind of address space virtual and physical. On the physical model (typically used by the kernel) the memory is bounded and each address correspond to physical ones.
The virtual ...