Questions tagged [interrupt]
The interrupt tag has no usage guidance.
158
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How to fix Parrot OS Installation interrupt? - common_interrupt: 1.55 No irq handler for vector
I was trying to install Parrot OS installation. But it appears the interrupt message if I install and it will stuck on the terminal
I already Flashed parrot os using balena etcher and after that I ...
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Linux socket modes of IO
There are three modes of i/o. They are Programmed IO, Interrupt IO and DMA.
My understanding is, Programmed IO requires CPU to busy-wait while Interrupt IO by nature, is ansynchronous.
Where can I ...
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Sleeping in kernel worker thread
I am reading about how interrupts defer work through workqueues.
From what I understood, the interrupt will enqueue work into a workqueue, and this will then be processed by a kernel worker thread.
My ...
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Assigning the interrupts using _PRT table
I am facing an issue where function 1 of the PCI device is unable to receive interrupts. I would like to understand how interrupts (legacy INTx) are assigned during Linux bootup based on the PRT table ...
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Any ready made script to pin the IRQ to the optimal CPU?
I'm not a expert by any means and I worry about doing wrong stuff... is there a standard / approved way to just run a script and have my interrupt tuned correctly on ubuntu 18.04 ?
I also have ...
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How is the process programmatically connected to an interrupt?
I know that an interrupt is a signal sent to a kernel asking for handling. In some cases we have a physical device like a keyboard with a driver that connects a process with an interrupt(key pressed). ...
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Restore original interrupt handler in linux
I removed the existing interrupt handler for the keyboard and registered my interrupt handler and after removing my interrupt handler, I want to restore the original interrupt handler for the keyboard....
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1
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359
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How does round-robin scheduling and context switching work from a low-level?
Using round-robin scheduling, the kernel provides time slices for different processes / tasks.
It seems that the kernel will initialize a timer, and when the timer times out, this will cause the ...
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How can the time command compute one millisecond from 4 ms timer ticks?
From the bash time command on different stock Ubuntu systems (both real hardware and VMs) all with CONFIG_HZ=250, I'm sometimes getting real 0m0.001s, user 0m0.001s or sys 0m0.001s as well ...
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705
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How to get more details on irq process in top?
I have irq/21-xhci-hcd displayed as the process consuming 90% CPU on top. There was also a lot of CPU time spent on servicing software interrupts (si).
This is on embedded Linux.
Does this mean that ...
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135
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Writing a kernel driver - knowledge of specific interrupt pins
I don't have knowledge about writing Linux kernel modules / drivers.
Let's take a basic example. I have an input device of my own which is connected to a microcontroller on one of the interrupt pins. ...
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455
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linux kernel freeze
I am using linux kernel 4.19 on intel (icelake) based server. Sometime immediately after linux boot (at the login prompt) it get stuck(once is 50 reboot or so). It is not responding to anything on ...
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Modify the number of interruption cat /proc/interruption
As you can see, when running the command cat /proc/interrupts, in the second column the number of interrupts delivered to each CPU per device driver.
test@test:~$ cat /proc/interrupts
CPU0 ...
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343
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Interpreting variations in LOCal timer interrupts number
Running a given workload in different CPU isolation (IRQs & processes) configurations, I do not observe significant differences among values (grand total) reported in /proc/interrupts & /proc/...
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260
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how to interrupt command initramfs
I have made a huge mistake. I'm currently loaded into initramfs, trying to fix an error similar to this post. I decided to cat /dev/XXXX, where I'm pretty sure XXXX is the main partition where Ubuntu ...
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498
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Halt execution of pasted multiline commands
I pasted a long list of commands into Bash, and in the middle of execution, I decided I wanted it to stop. Ctrl+Z and Ctrl+C did nothing. It just continues executing line after line. In the end, the ...
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Setting a trap for INT doesn't work in a subshell
$ bash -c "trap \"echo INT\" INT; sleep 3" & pid=$!; sleep 1; kill -INT $pid; wait
[1] 27811
INT
[1]+ Done bash -c "trap \"echo INT\" INT; ...
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268
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EXIT trap is ignored on Ctrl-C when PID == 1
a.sh:
trap 'echo cleanup' EXIT
sleep 3
To reproduce, press Ctrl-C before the script finishes:
$ docker run --rm -itv $PWD:/app -w /app alpine:3.14 sh a.sh
^Ccleanup
$ docker run --rm -itv $PWD:/app -...
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Can APIC LVTERR on AMD be configured as NMI message type?
In fact, the message type / delivery mode of LVTERR on Intel is unconfigured.
However, on AMD, it is presented as below.
The problem is, when I configure the MT of LVTERR on AMD as NMI, it will keep ...
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388
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Does the worst PCIe MSI interrupt latency jitter over 100us normal?
I try to figure out the values of interrupt jitter in Linux, especially in the worst cases.
Two testbeds are considered, one is Raspberry Pi 4B, the other is a high-end PC with an intel i9 CPU and ...
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Copying text with Ctrl + C when the Zsh line editor is active
I've added some keyboard shortcuts in my Zsh to enable selecting words.
In order for the selection to do something, I would like to use Ctrl + C to copy it. However I would also like to use Ctrl + C ...
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95
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Role of Advanced Programmable Interrupt controller in system?
I am trying to understand interrupts at both the hardware and OS level.
Why exactly we need an APIC controller in a system. I understood that it is doing some multiplexing and only one line is going ...
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523
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Why does a system call table exist and not just appended to the interrupt vector table?
Why does a system call table exist and not just appended to the interrupt vector table? I don't understand the design choice here. If it improves performance to differentiate events, why not system ...
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infinite loop VS sheduler
From assembler point of view, when we make a code that just jumps a few commands back, does not jump to any control function that sheduler might use, how can unix interrupt such a code?
I assume it is ...
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Why does SIGINT not terminate a stopped process?
According to the POSIX standard regarding signals (see "Standard signals" section), both SIGKILL and SIGINT have as default action Term. However, this seems not to be the case when the ...
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43
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How are big values stored in linux?
For example, cat /proc/interrupts.
I see this value is constantly growing -
36: 10273035 IPIC 36 Level eth1_g0_rx
What happens when it reaches its maximum value: that is the maximum ...
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901
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Is it safe to restart system calls?
I was reading a textbook which describes how to deal with system call when interrupted:
System calls can be interrupted. System calls such as read, wait, and accept that can potentially block the ...
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223
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Ctrl + C Not terminating a process in Linux
I am building a custom Linux Image using Yocto Zeus (5.4 Kernel). On loading and checking the various functionalities of the Image, I am not able to exit some of the processes such as ping, tail -f in ...
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Do system calls actually "interrupt" the CPU the same way that hardware interrupts do?
I'm trying to get a deeper understanding of how system calls and hardware interrupts are implemented, and something that keeps confusing me is how they differ with respect to how they're handled. For ...
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Hardware timer , Real time clock, Jiffies in Linux context
I am trying to understand the Timer interrupts and the associated terms used in an x86_64 Linux machine.
Hardware timer (External clock) is same as a Real Time Clock.
The Real time clock runs even ...
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537
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Broken my pop-OS while upgrading
I mistakenly broke my pop-OS and when I restart it then I get an error window with
**Error occured which system cannot restored. Contact administrator**
I already tried apt-get dist-upgrade in ...
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240
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__report_bad_irq not getting hit
I am stucked in one issue, in which i am getting __report_bad_irq callstack inconsistently.
AFAIK, whenever we have 100000 unhandled interrupts this stack kicks in.
Output from cat /proc/irq/128/...
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355
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Handling an interrupt while being on kernel [closed]
I know how interrupt handling works (switching mode, saving registers, changing stack ...). However, I am curious, what if an interrupt happens while we are still in kernel mode, and not in user mode?
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157
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redhat 7.7 nohz_full dynamic tickless behaviour
I'm trying to set dynamic tickless behaviour on certain cores (cores 2 - 11), moving all timekeeping to the only unspecified cores (cores 0-1). However, when I perform the instructions specified in:
...
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How interrupt is queued up in linux?
In hardware and software interrupt flow how queue up is handled? more precisely I have following doubts
Lets take a scenario I have a machine with 2 CPUs. CPU1 is processing process P1 and CPU2 is ...
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Is it safe to use the .bss section as a static stack?
(This is in the context of x86-64 Linux.)
I am trying to write a high-reliability userland executable, and I have total control over the generated assembly. I don't want to rely on automatic stack ...
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503
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Custom interrupt handler for the NMI hardware button
I'm trying to create a custom interrupt handler for the NMI hardware button which exists on my motherboard.
To test this functionality I've created this simple module:
#include <linux/init.h>
#...
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Would an asynchronous interrupt context write to the page table in the Linux kernel?
Specifically, in the Linux kernel, is it possible that the page table (level3_kernel_pgt) can be overwritten when an asynchronous interrupt context happens (Local timer interrupts).
I've been seeing ...
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System interrupts. When is it too much?
We're testing Linux Server as a VPN router.
We have a quite good server and the interrupts we're experiencing right now are ~170k, but we're expecting more. CPU usage is OK. How to know when it's too ...
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Why we have so many 0's in intr field of /proc/stat
I am looking into intr field of /proc/stat.
# cat stat
cpu 10438 2056 25767 10098612 2490 0 1846 0 0 0
cpu0 1768 260 4750 1681597 119 0 608 0 0 0
cpu1 1735 67 5119 1683444 342 0 280 0 0 0
cpu2 1908 ...
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813
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Notify user-space about interrupt, sleep otherwise
As a beginner, I want to know what people think would be the best course of action for the following scenario. I have a driver that handles a rising-edge interrupt on a gpio pin. The driver also has a ...
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Linux timer interrupt
I have two questions about the Linux kernel.
Specifically, does anybody know exactly, what Linux does in the timer interrupt? Is there some documentation about this?
And what is affected when ...
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What is the hardware which the linux kernel uses for timer interrupt
I am reading about jiffies which will be updated for every timer interrupt. The frequency of the timer interrupt is determined by compile time constant HZ.
We have lot of hardware devices present on ...
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Interrupt child processes from bash script on Ctrl+C
I'm starting two child processes from bash script and waiting both for completion using wait command:
./proc1 &
pid1=$!
echo "started proc1: ${pid1}"
./proc2 &
pid2=$!
echo "started proc2: ${...
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How does a keyboard press get processed in the Linux Kernel?
I'm currently learning about the Linux Kernel and OSes in general, and while I have found many great resources concerning IRQs, Drivers, Scheduling and other important OS concepts, as well as keyboard-...
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Manjaro/Arch: Disabling IRQ #31 on Thinkpad X1 7th
I've stumbled upon the beforementioned error during boot and have tried to resolve it by trying to find out what caused the interrupt.
Sadly, lspci -v | grep 31 gives no result and a cat /proc/...
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What are the non-numeric IRQs in /proc/interrupts?
cat /proc/interrupts shows a bunch of IRQs such as NMI and LOC. The per-line comments in the output give clear explanation, but if they do not have a numeric IRQ number, how does the x86 CPU respond ...
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1k
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Dump contents of variable to file while script is running in bash
I have a lot of files in a directory:
$ ls
file000001
file000002
# ... truncated ...
file999999
I am calculating the md5sum of the files like this and finally dumping it to a file:
hashes=''
for ...
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How to deduce the nature of an interrupt from its number?
I'm trying to boot/install Linux for learning purposes, using an older PC (HP Pavilion Elite m9660de). The following message is the first thing that shows up when booting (Ubuntu and Fedora, both from ...
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How fast is an IO interrupt in Linux versus bare metal? (ARM, Raspberry Pi)
I read that an interrupt in Linux (this was about a Raspberry Pi) can take a "long time" to process or let's say "start doing what the programmer wants". Is that true and how bad is it?
Is there a big ...
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