Questions tagged [kernel]
Everything about Unix kernels: development, configuration, compilation, design, etc.
3,614 questions
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Why does Linux CFS need a periodic timer interrupt more frequent than the time slice?
OSTEP says
Note that CFS utilizes a periodic timer interrupt, which means it can only make decisions at fixed time intervals. This interrupt goes off frequently (e.g., every 1 ms), giving CFS a chance ...
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file-nr keeps increasing forever
I have a cloud VM running linux-yocto 6.17 and a few daemon processes--postfix, dovecot, rspamd, nginx, sshd, fail2ban and redis.
Ever since upgrading from 6.11 to 6.17, I've noticed that /proc/sys/fs/...
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How to set charging threshold of a Toshiba laptop directly from Linux
I just had to order a new battery which died after just one year of usage. Apart from the cost, this is a bit environmentally wasteful - waste of lithium and rare earths. So now I have learned that ...
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Fast question about gnu-libre kernel
This kernel is identical to Linux official kernel but they remove all proprietary binary firmware and there is not possibility to load it, this mean more safety and more os.
https://linux-libre.fsfla....
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kernel panic after suspend starting from kernel 6.16
I've a problem with kernel versions starting from version 6.16. it was working in kernel 6.15.
In kernel 6.15, when I put my laptop to sleep and resume from it, the Wi-Fi does not resume. So I am no ...
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How to interpret the refcnt field in /proc/crypto?
Here's an example /proc/crypto entry:
name : md5
driver : md5-generic
module : kernel
priority : 0
refcnt : 1
selftest : passed
internal : no
type : shash
...
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Cross compile for ppc64 kernel, no way to generate Debian package?
I start to cross-compile a kernel for an old ppc64 machine using a fast amd64 machine.
I have installed all deps
apt -y install bash-completion make build-essential linux-source bc kmod cpio flex ...
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ps ax and -o fd
According to ps(1), ps doesn't support fd.
even I didn't find fd in task_struct of kernel.
How can I find fd of a program?
َUPDATE:
FD means File Descriptor.
When I get query from services such as :
...
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Process Maps in s390x linux systems
So I am working on a debugger for linux s390x system and have the whole disassembler etc set up for reading the ELF file. For debugger I just run it on the process with base address from the process ...
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linux kernel - (virtual) bluetooth device for testing
I want to test and debug linux kernel internals within the bluetooth stack, i.e. /net/bluetooth. I have a (rather minimal) kernel, manually built, with debug symbols, and a busybox at the moment, ...
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How hid-generic driver catch the event from the mouse device
I have some questions regarding the hid-generic and implementing my own driver.
Below is the hid-generic source code.
hid-generic.c source code
My questions are:
How does the hid-generic driver ...
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Try netconsole in single machine, but not working
Some basic info of my machine:
# uname -a
Linux iZ2zeirtviyt9b8s96ery2Z 6.8.0-40-generic #40-Ubuntu SMP PREEMPT_DYNAMIC Fri Jul 5 10:34:03 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
# ip addr
1: lo: &...
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Trying to compile a tinycore linux kernel leads to Error 2
EDIT 1 - Following instructions from : https://github.com/on-prem/tinycore-kernel
EDIT 2 - after trying make os, it fails giving an Error 2 compiler error. i know that it has something to do with the ...
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Btrfs can see only half of the disk, bug or feature?
I think I have found a bug in btrfs, but I am not sure. At least the following script, very likely, can demonstrate it.
This script creates an 1TB big file in /tmp/btt, formats it as a btrfs and ...
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RHEL 9 GRUB not booting automatically to the latest kernel
I have noticed a strange behaviour on some RHEL 9 servers:
GRUB does not boot on the latest kernel, despite the fact that
it is supposed to do so automatically whenever a new kernel is installed, and
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how do i get complete list of external firmware which is being loaded by the kernel during boot
I am compiling my own monolithic kernel for my Lenovo laptop. I am using the CONFIG_EXTRA_FIRMWARE= to specify which firmware files should be build into my kernel staticlly.
with my older laptops, it ...
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I want a Boot animation like Ubuntu's and can't seem to be able to get it
I've been using Debian 12 for the last couple of years and decided to give Ubuntu 24.04 a chance, first thing I noticed is that the boot animation starts at the very beginning of the boot up sequence ...
MartínVargas
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Why does there appear to be a discrepancy when trying to programmatically access files associated with different tasks in Linux from kernel space?
As a way to better understand Linux kernel structures, interacting with and pulling information from these (and also getting more experience coding in C), I've been building simple kernel modules to ...
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PCI correctable errors on my SSD
I am on Ubuntu 22.04 LTS, and I have a Western Digital WD Black 500Gb NVME2 ssd. The laptop is a Dell E5495.
I installed a fresh Ubuntu (previously was Windows 11), but I continuosly get the following ...
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When memory is allocated using kmalloc, is a virtual memory address with an already established PTE (Page Table Entry) returned?
When memory is allocated via kmalloc (i.e., slab cache allocation like slab_alloc_node), it returns a virtual memory address. Presumably, when accessing this virtual address, the corresponding PTE (...
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Recompiling my custom kernel and my .config is set to old config every time
I am trying to recompiling my kernel. I did a small change in drivers/media/usb/uvc/uvc_driver.c and put a pr_info() only to see in dmesg if its working.
I changed the .config file too in ...
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Does a .h file for external kernel modules need compilation in another, particular manner?
I have an external kernel module and a Makefile. I was using Kbuild but decided to go with a straight Makefile and make. I have my headers installed, build-essential and kmod installed, and I am ...
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How to set new features to N during kernel compilation from an old .config file?
I am compiling a custom linux kernel for a compute cluster. The cluster is currently running on kernel version 4.4.47 since last 5 years. I need to upgrade the kernel to a more recent version. I've ...
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Kernel Boot custom init script and rootfs
i am using passing a script as init= for kernel boot.
I use this script to setup overlayfs using two partitions on an mmc device.
This works fine.
I use root=/dev/mmcblk0p1 as the root.
at boot, i ...
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Is SMI the same as managed IRQs? How can I know if a IRQ is a managed IRQ?
On the IRQ affinity tuning subject. I've realized that some IRQs cannot be reassigned to other cores.
I've read[1] that those are called "managed IRQs". On the Linux Foundation wiki, I've ...
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