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Questions tagged [kernel-modules]

Use this tag for questions about loading, configuring, or compiling them. See also /drivers for questions about which modules to use for specific hardware. A kernel module is a bit of code that can be added into the kernel by the administrator while the system is running, typically providing one feature such as a filesystem.

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Gre protocol being treated as invalid state in iptables rule

Linux box acting as a router (eth0 - WAN, eth1 - LAN), with sysctl net.ipv4.ip_forward=1 With enabled automatic connection tracking helpers: echo 1 > /proc/sys/net/netfilter/nf_conntrack_helper ...
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How to additional public keys to .secondary_trusted_keys?

I am trying to add additional keys to .secondary_trusted_keys. Documentation says, to do so the additional keys has to be signed by a key which is already a resident in either .builtin_trusted_keys or ...
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How does Linux actually perform protocol data unit (PDU) encapsulation?

I understand that as data goes from the upper layers (Application Layer) to the lower layers (Physical/Link Layer(s)), the data is encapsulated. When it goes back up the layers, it is decapsulated. ...
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Order of kernel upgrade commands for gentoo

I have simple bash script to update the kernel. It includes building the kernel, rebuilding external modules, building initramfs with genkernel and updating grub config, here is the script: #!/bin/...
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can't load iwlwifi nonfree firmware after kernel update

My hardware requires the iwlwifi nonfree firmware for working wifi. With the latest kernel version however it stopped being able to load it. The last working version is 4.9.0-7 while 4.9.0-8 does not ...
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USB/IP installation on Oracle Linux 7 for VirtualHere client

I am trying to use VirtualHere Linux console client on an Oracle Linux 7 box. However the client fails to start with an error: [root@hostname ~]# ./vhclientx86_64 modprobe: FATAL: Module vhci_hcd not ...
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Communicating between userland and kernel space (KEXT) on MacOS

In order to make it easier to develop a kernel module, I am considering Loadable kernel modules (LKMs) on MacOS. This way you have a base kernel module and your main kernel module which is an LKM ...
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How to verify a kernel module signature?

When you compile a kernel source, you can choose to sign kernel modules using the CONFIG_MODULE_SIG* options. The modinfo tool should handle the task of verifying the module signature, but there has ...
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data race within ptr_ring code implementation [migrated]

I am implementing single-producer,single-consumer ptr_ring buffers. Are there really data races within this linux driver code ? I asked this because ThreadSanitizer gives me error and my system ...
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1answer
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Access grab state of evdev device

I need to retrieved the grab state of an evdev device in a program. More specifically, I need to retrieve the state of the grab pointer in the evdev struct seen here: https://elixir.bootlin.com/linux/...
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How to find kernel module for a given device?

I am trying to troubleshoot a problem: usb mouse doesn't work on a freshly installed linux. I suspect the problem is that there is no suitable kernel module/driver for my usb hardware. Indeed: $ ...
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What happens to memory that wasn't freed in a kernel module after unloading?

Suppose I called kmalloc and didn't free that memory before rmmod was called on the module, what happens to that memory? Is it a memory leak and it is completely unusable until restart, or does the ...
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1answer
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mismatch between kernel version and kernel header

I use an embedded with a bit old kernel 2.6.37. Now we need to update rootfs with more update gcc than the one used on building the image (Instead of 4.3 need to use 5.1, because it will support c++11,...
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1answer
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Discover WiFi driver with Ubuntu to install on CentOS 7

I installed CentOS 7 Minimal on a Yoga Pro 2. However, I'm not able to "up" the WiFi device w1p3s0 despite following numerous guides with ip link, nmcli and nmtui. The same guides work very well when ...
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Kernel driver, is pinctrl-0 property always needed with GPIO overlay?

I'm creating a kernel driver for SPI controlled display, which is meant to be working with Raspberry PI. I'm not sure about a one thing that I see sometimes in device tree overlays created by other ...
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How to build existing kernel modules from github “linux/drivers/”

I want to load kernel modules using modprobe. However, because I don't have the .ko-file yet, I need to build them before. In my case the one I want would be in the path /lib/modules/$(uname -v)/...
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2answers
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Selinux is blocking my external kernel module

I'm trying to insert an external kernel module in permanent mode. During the boot, my module is being loaded by systemd-modules-load service so long as Selinux is permissive. But I want to keep ...
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modprobe gives: “FATAL: <module> not found in directory” error [duplicate]

I am running standard raspbian on Raspberry Pi-3. pi@raspberrypi:~ $ cat /etc/os-release PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)" NAME="Raspbian GNU/Linux" VERSION_ID="9" VERSION="9 (stretch)" ID=...
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Does the Linux Kernel use event-loops to keep itself alive? [duplicate]

I am just wondering what mechanism does the Linux Kernel program use to keep itself alive. Any normal C program will terminate by executing its statements sequentially. If we wanted to keep that ...
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1answer
218 views

Ryzen/Threadripper temperature sensors: Which senors are related to which kernel modules and how to enable them

What sensors I can monitor on my AMD Threadripper 1950x on an ASRock x399 Taichi mobo under Linux. It was announced last year that temperature monitoring was working for Ryzen processors and that was ...
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1answer
125 views

Adding iptables to yocto causes image do_rootfs to fail

My image builds nicely with kernel 4.13 (set in local.conf) and all of my recipes. When I try to add the iptables recipe (v1.6) to my image, the do_rootfs task fails with the following error: ERROR: ...
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1answer
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Find what program accessed a kernel module

How do I access a list of users/programs that accessed a certain module? I run: lsmod | grep ^uvcvideo This returns this line when no application is using my video camera: uvcvideo ...
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1answer
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Could not find libmount

During compilation of customized distribution (using buildroot v. 11.2018) I have problem with libmount library (the problem appeared after I had included efl package in buildroot menuconfig - Target ...
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1answer
127 views

Unable to load SFP+

I am using CentOS7 7.5.1804. I have a Intel 82599 based 10gig SFP+ card. When I try my SFP's I get: failed to load because an unsupported SFP+ or QSFP module type was detected. I tried everything I ...
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Custom RK3288 board with AP6212A - BCMDHD driver kernel hang

I have a RK3288 based custom board with AP6212A wifi/bt chipset. I am using rockhip-linux 4.4 with bcmdhd driver. It is using the SDIO protocol. After the driver loads the kernel freezes when it tries ...
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1answer
48 views

/proc/meminfo says VmallocUsed is 0. So where are my kernel modules stored?

I thought the code for kernel modules was stored in a vmalloc() allocation? (In fact I'm sure the kernel code is using vmalloc(), not kvmalloc()). So why does /proc/meminfo say I have no zero ...
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1answer
55 views

Error building virtualbox pci-passthrough kernel module - what went wrong?

I am trying to get virtualbox working on my machine with the pci-passthrough extension. When trying to run a VM, I got this error message: Kernel driver not installed (rc=-1908) [message asking me to ...
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1answer
377 views

modprobe: FATAL: Module fbcon not found. Number of created screens does not match number of detected devices

I am using debian. I recently have purged X11 and xcfe4 and reinstalled them both but whenever I lauch Xorg --configure I get this: (++) Using config file: "/root/xorg.conf.new" (==) Using system ...
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1answer
46 views

What do “ACard AHCI SATA low-level driver” meaning? What is “ACard”? [closed]

I run on Debian Stretch,my linux-kernel version is 4.14.13 Is this module never used(real loaded) in initramfs for desktop PC? The context is for initramfs and I have a very slow usb storage device(3....
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2answers
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What ELF types do kernel itself and kernel modules have?

https://linux-audit.com/elf-binaries-on-linux-understanding-and-analysis/ says The type field tells us what the purpose of the file is. There are a few common file types. CORE (value 4) DYN (...
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1answer
117 views

How does Linux kernel dynamically use a module?

Understanding the Linux Kernel says The kernel has two key tasks to perform in managing modules. The first task is mak- ing sure the rest of the kernel can reach the module’s global symbols, such ...
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2answers
665 views

Reduce Boot time

I would be interested in finding ways to reduce the boot time, specially in embedded-related environments. I've read somewhere of a method to avoid the kernel to load some drivers or modules but I'm ...
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47 views

i2cdetect -l don't return anything [closed]

I need to use the SMBus, but when I run the command i2cdetect -l I do not receive anything as output, on Windows it was recognized, I do not see anything about SMBus even doing lspci. I installed and ...
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0answers
85 views

Compiling module on OpenWRT: make can't find build directory

My setup: OpenWRT 18.06.1 Raspberry Pi 2 B Kernel 4.9.120 Attempting to build a very simple hello world kernel module results in the following error: # make make -C /lib/modules/4.9.120/build M=/...
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1answer
187 views

lsmod 'used by' shows -1 while CONFIG_MODULE_UNLOAD=y

In this post there is some explanation about why does lsmod show -2 in 'used by' column. The idea is that the kernel config option CONFIG_MODULE_UNLOAD was not set. But what if lsmod shows -1 only ...
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1answer
234 views

Compile Linux kernel module without Module.symvers

I have this embedded Linux devices. I would like to add kernel-level functionality to it, but would highly prefer not to compile my own kernel to do so. (If the kernel doesn't load and get to user ...
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1answer
256 views

Force loading kernel module at startup

Some of my hardware needs the module cx23885. For some reason modprode cx23885 doesn't work, instead only modprobe cx23885 --force-modversion works. This hardware is currently somewhat buggy and ...
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How to insert a module in qemu where module is in guest system?

I am running qemu first time so I don't have much knowledge of it. I am having a kernel module hello.ko and I want to insert it in kernel using insmod in an OS running in qemu and this module is ...
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Crypto CBC module doesn't show up in /proc/crypto

I want to decrypt an old volume that's using aes-cbc-plain So I am on arch linux kernel 4.9.130 I enabled the cbc as modular in the kernel and installed the modules and the kernel. CBC shows up in /...
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1answer
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Kernel module shows me 8 processors instead of 4 for Intel i5-2500K

My question mostly about hardware, specifically the Intel i5-2500K CPU which Intel describes as having # of Cores 4 # of Threads 4 Linux shows me 4 processors: $ cat /proc/cpuinfo | grep ^...
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1answer
730 views

Signed kernel modules - “not signed with trusted key”

Issue: I'm trying to use signed kernel modules, but getting a failure for the insmod command: PKCS#7 signature not signed with a trusted key There is a potentially related error message during ...
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1answer
202 views

Linux CPU soft lockup, kernel tained, system hung [closed]

Recently, some Linux VMs got an abruptly significant increase in CPU speed,then system hung. Sometimes, thete is no reported crash log at all. Below is the message that show up when CPU soft lockup ...
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1answer
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Persistent module loading not working

Red Hat 6 2.6.32-754.el6.x86_64 I've been working away on two drivers, one is a DMA driver that talks to a PCIe FPGA card. The other, a network driver. The network driver has a dependency on the DMA ...
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udev not loading a module

I'm trying to get udev to load the brcmfmac driver as a module but for some reason it's not detected unless I create a .conf file in a /modules-load.d directory (either in /etc or /lib). As far as I ...
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193 views

Cannot load compressed Kernel module?

I tried to load "hid-a4tech," but I got error the messages below: [net_client@netarchwork ~]$ modprobe hid-a4tech modprobe: FATAL: Module hid-a4tech not found in directory /lib/modules/4.18.7-...
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1answer
217 views

Changing a built-in kernel module parameter at booting time?

I am trying to change a parameter, called "sgl_threshold", in the nvme driver when booting into Ubuntu 16.04 running linux kernel v4.18-generic. It appears the nvme driver is actually built-in as it ...
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1answer
38 views

TCP variants under lsmod

I was reading about how TCP congestion variants are implemented in Linux. Each variant is implemented as a separate module. When I had read this question: Add TCP congestion control variant to Linux ...
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1answer
24 views

My Kernel modules don't match those of the VirtualBox installation guide. Should I be concerned?

Fabian Lee : Software Architect's steps to installing VitualBox: Make sure the kernel modules (vboxnetadp,vboxnetflt,vboxpic) were loaded properly: $ lsmod | grep vboxdrv vboxdrv 446464 3 ...
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what is inside weak-update folder?

First, installed a driver package to OS (ex: CentOS ) -- foo_1.0.rpm Second, install the same driver but different version -- foo_2.0.rpm by rpm -ivh --force foo_2.0.rpm It seems an extra folder ...
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1answer
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How to disable a driver from reopening when connecting a device it recognizes?

After doing sudo rmmod usbhid the usbhid driver only reopens when I connect a device, which I don't want because I want to write a custom driver for it and I need it disabled until I say otherwise. ...