The kernel of operating systems popularly known as Linux, or sometimes GNU/Linux.

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How can i retrieve the following attributes in linux? [on hold]

Reads (transfers per second ) between system memory and user memory writes (transfers per second) between system memory and user memory Number of system calls of all types per second Number of ...
0
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10 views

embedded linux- to check uart in raspberry pi

Checking whether the Pi is sending and receiving UART data by installing the tool Minicom. Pi is sending serial data but is not receiving data. Whatever I type in Pi minicom is received to PC ...
2
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1answer
2k views

How to fix make error “No rule to make target 'menuconfig'” when building a kernel for Beagleboard?

The aim is to build and install the USB Video Class (UVC) module, via make modules_install. I'm trying to configure the kernel via make menuconfig on Angstrom distribution, running on BeagleBoard-xM. ...
1
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0answers
15 views

Why I can not update Linux core in dockers?

When I run apt-get update && apt-get upgrade in container, the core is not starting to update. Yes, I know, containers use the kernel of host machine and can not execute some ...
2
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1answer
12 views

Help in building Yocto(open embedded) projects using cluster computing in Linux

I need to reduce project build time in Yocto (open embedded) in Linux platform. So I decided to cluster computers for the best performance for compilation and building. My question: Is there any MPI ...
1
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0answers
11 views

How connected are kernel modules to kernel version?

I'm wondering how custom ROMs port new versions of Android (particularly the Linux kernel) to old phones. As I understand, Linux allows closed source kernel modules. If so, then when the phone ...
0
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0answers
23 views

How to get proof that Kernel Oops has happened? [on hold]

I crashed a program on purpose, but I can't figure out a way to "prove" that a kernel oops has happened. I tried using dmesg but that only displays on the screen. Is there a log or any other methods ...
-1
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0answers
13 views

What are front merges in I/O scheduling and how can I tune this parameter? [on hold]

My Linux uses the Deadline algorithm for I/O scheduling. One of the parameters is the front_merges parameter under /sys/block/sda/queue/iosched/front_merges. By default it is set to 1, which means ...
29
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3answers
50k views

Linux: How to find the device driver used for a device?

If my target has one device connected and many drivers for that device loaded, how can I understand what device is using which driver?
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2answers
39 views

Booting stops at Loading initial ramdisk

I have installed Arch Linux on 40GB HDD on ga-g4mt-s2p1 Motherboard ( Intel Core 2 multi-core,2Gb of Ram) I have made 4 Partitions: /boot 100Mib Swap 4Gib / 20Gib /home The rest of the disk It ...
8
votes
2answers
7k views

How to tell whether RAM ECC is working?

I'm planning on getting some ECC RAM to replace the non-ECC RAM I currently have installed on my Asus M5A97 Pro motherboard (AMD 970 chipset, FX-6100 CPU). After I install the RAM, how do I tell ...
0
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2answers
65 views

Troubleshooting new linux system keeps freezing

I just built a new computer and installed centos7 (RHEL based) and I also tried mint 17.3 (Ubuntu based). Installation goes without any problems. The operating system runs smooth and everything is ...
6
votes
1answer
10k views

Device eth0 does not seem to be present, delaying initialization

I have cloned a fedora and now trying to configure network interfaces. Every time i am adding a new NIC, it starts with number eth3 (rather eth0). i have tried removing and modifying the ...
2
votes
1answer
450 views

how do I safely delete old kernel versions in CentOS 7?

I might be encountering odd symptoms resulting from competing kernels in CentOS 7. So how do I safely delete the old kernels? And how do I know which kernel is the newest one? Below is the ...
1
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0answers
29 views

Linux kernel, missing '__fentry__' symbol

Trying to build the EtherCAT master driver (realtime I/O driver) on a RT Linux (SL6.3) I keep bumping into a missing symbol issue when building the EtherCAT kernel modules: # make modules make -C ...
0
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0answers
13 views

Attach UVC camera to non-V4l2 Android device without rooting

The main issue is arising when I am trying to connect UVC compliant camera having CMOS sensor OV6612, to an Android device having kernel 3.0.x and OS 4.0.x, not having v4l2 driver. And no streamed ...
6
votes
3answers
951 views

Location of the kernel binary (when not in /boot)?

I failed to find the kernel binary in the standard location in /boot. I've also searched the whole file system for vmlinux or bzimage find / -iname vmlin* find / -iname bzimage However, this is an ...
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0answers
19 views

how to compile and load a kernel module? [duplicate]

I want to compile a kernel module that is have makefile, .c file and .h file how i can compile it for arm cpus an how i can load this kernel module. --This is my makefile : KERNEL_DIR := ...
-1
votes
1answer
99 views

Linux not using all memory

I have a PC with Fedora 23 OS with 4 GB RAM, but usable memory is 2 GB. When I tried to check memory: # dmesg | grep Memory [ 0.000000] Memory: 1753008K/1816676K available (7670K kernel code, ...
23
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1answer
15k views

Linux: What is a tainted kernel?

Under certain conditions, the Linux kernel may become tainted. For example, loading a proprietary video driver into the kernel taints the kernel. This condition may be visible in system logs, kernel ...
6
votes
3answers
497 views

What prevents distributions from using the latest Linux kernel? [closed]

Most Linux distributions ship with a certain kernel version and only update it on point releases (x.y.z to x.y.(z+1)) and for security updates. On the other hand, I know that Linux has a very strict ...
1
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0answers
15 views

Where in Ubuntu SPI pins are configured?

I'm running Ubuntu on a custom embedded system. The SPI bus master is spi-pxa2xx. I've tried my code on several other systems and it worked fine. But on this system all I see is CS activity while I'm ...
0
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1answer
13 views

Linux tools for perf (install linux-tools-3.15.0)

I use Linaro version of Linux (Linaro 12.11) on my embedded target with ARM9 Core. For a certain profiling, I need to use the perf tool. perf require linux-tools-3.15.0 to be installed on my device. ...
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0answers
9 views

Remotely use a platform device

I have a linux/android device with a certain hardware module (lets call this pc A), and a driver which uses the hardware as a platform device. Because of testing/os restrictions I'd like to be able ...
3
votes
2answers
6k views

GRUB2 and kernel vga= parameter

According to the documentation, use of the vga= kernel parameter is deprecated as of GRUB2. The fact that some newer kernels don't seem to support it anymore on certain adapters is of no concern as ...
3
votes
1answer
23 views

Does the O_DIRECT flag bypass the Linux page cache when accessing block devices too?

I am running a lot of KVM virtual machines, which open the hard disk image with the O_DIRECT flag. I understand, according to the open() man page, that using O_DIRECT will try to bypass the Linux ...
2
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2answers
46 views

Is there any way to hide kernel threads from ps command results?

When I type ps -ef , there are lots of special kernel thread processes showing. I am not interested in kernel threads; I am only interested in user process/thread. Is there a way that I can hide the ...
1
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2answers
707 views

Determine whether kernel built-in driver supports a device

I'm trying to find a way to accurately determine whether all the hardware on some system has a valid driver installed either via a kernel module or built-in to the kernel. I'm working with RHEL 5.5 ...
1
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2answers
2k views

File system CRC check

I know that before running the kernel, u-boot (the boot loader) will check the kernel image CRC. Only if it is correct it will go further, else it will give a "Bad CRC" error. I want to do same thing ...
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0answers
8 views

How much control do concrete file systems have over the VFS inode cache and the buffer cache?

I want to make sure I'm understanding how VFS inodes and file system inodes working together. A file system's inodes are stored on the block device and that is where they live. When an operation is ...
3
votes
3answers
77 views

how to monitor a unix directory and if any new file in directory it will be copied to another directory

I want to monitor a unix(Solaris 10) directory and if there is any new file i want to copy immediately. Tried: I have shown inotifywait and incron package in linux for it but i don't know whether it ...
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0answers
14 views

Booting into linux kernel 4.1.3 using qemu

I am trying to boot into a compiled Linux 4.1.3 bzImage (disabled modules, so I only had to make bzImage). Correspondingly, I installed ubuntu 15.10 (with Upstart, not systemd) on a qemu cow2 image ...
2
votes
1answer
663 views

Enable kernel's net_key, inet_esp, crypto_hmac modules for to use in a VPN

I'm trying to turn on modules for VPN so I followed this tutorial to compile new ubuntu kernel 3.8.6 . But the features I've turned on using make menuconfig seem not to be enabled. (the features I ...
0
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0answers
23 views

Dereferencing string pointer in ftrace event filter

I'm currently trying to create an ftrace event filter for the event sys_enter_open which is filtering by the filename argument. Looking at the format definition of it I can see there's a filename ...
0
votes
1answer
33 views

make + bash: setting environment variables on command line doesn't work

I am trying to build the kernel for Raspberry-pi on my Debian-8 host machine. I passed the following commands to build the kernel make ARCH=arm KERNEL=kernel CROSS_COMPILE=arm-liux-gnueabihf- ...
25
votes
1answer
6k views

Configuring, compiling and installing a custom Linux kernel

I'd like to try using a kernel other than the one provided by my distro -- either from somewhere else, or as customized by me. Is this difficult or dangerous? Where do I start?
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10 views

init & System V IPC in kernel

Does it affect init if System V IPC is not compiled into a kernel? Does init require System V IPC?
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0answers
20 views

Add a module to linux kernel source code statically [closed]

I am new to linux kernel programming. I have explored that there are two ways of adding modules to linux. One way is by dynamically linking the modules with the running kernel using insmod and another ...
0
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1answer
906 views

Issue with Hugepage reservation in linux

I have reserved hugepages for my process using below commands: #echo 64 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages #mkdir -p /mnt/huge && mount -t hugetlbfs nodev /mnt/huge ...
1
vote
1answer
2k views

kernel: “echo 0 > /proc/sys/kernel/hung_task_timeout_secs”

I got this errors in syslog. Any idea what does it mean? The system is running on Ubuntu 12.04, kernel: 3.8.0-35-generic #52~precise1 It looks to me like failure when trying to write to disk... ...
0
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0answers
10 views

Changing the Retransmisson Timeout (RTO) estimation in Fedora

Retransmission Timeout(RTO) in a TCP plays a vital role in the internet. There are many algorithms proposed for calculating the Retransmission timeout. RFC 6298 is used for the estimation of RTO. I ...
3
votes
1answer
40 views

Why does Linux scheduler have locks for run queues?

Why does Linux Kernel Scheduler code have locks for run queues? Does the scheduler spawn kernel threads, and locks are to prevent two of such threads to avoid modifying run queues at the same time?
3
votes
1answer
50 views

Can the kernel symbols' addresses be influenced? consequences?

tl;dr: in my distros linux 3.08 kernel using cat /proc/kallsyms I can find out that for instance the _commit_creds function/symbol is located at address 0xc1073fe0. When either: building my kernel ...
1
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0answers
16 views

Why are there no LSM hooks in the POSIX IPC APIs?

As I understand it, the Linux Security Module (LSM) framework has many hooks which are callbacks for security modules to register functions performing additional security checks before ...
0
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1answer
785 views

custom kernel and firmware loading

After I have compiled my kernel, and when I type make modules_install, not only are the modules copied into /lib/modules/ but also firmware is copied into /lib/firmware/. The following is the end of ...
3
votes
1answer
53 views

how to eject/unmount usb dongle logically?

We've bought a commercial application who just work only if their dongle usb is connected to the server. However sometimes the application can not recognize the dongle, so it doesn't work, but if ...
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0answers
48 views

Compiling a single kernel module which resides in the kernel tree

I have updated my Linux kernel to 4.3.3, everything works smooth except my webcam (QuickCam® Pro 9000) which is not working. According to the dmesg, the kernel recognizes the I have plugged a usb but ...
19
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4answers
6k views

How to tell Linux Kernel > 3.0 to completely ignore a failing disk?

I am asking this question here in the hope that some Linux-kernel guru can have an answer. This question has been asked on AskUbuntu and on SuperUser without answers: thinking better, it is really ...
3
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4answers
145 views

Restrict size of buffer cache in Linux

Is there a way to tell the Linux kernel to only use a certain percentage of memory for the buffer cache? I know /proc/sys/vm/drop_caches can be used to clear the cache temporarily, but is there any ...
2
votes
1answer
46 views

Why does Linux have a maximum number of sound cards? [closed]

I'm specifically asking about CONFIG_SND_MAX_CARDS in the kernel. From the code using this config, for example in sound/usb/card.c for USB cards, soundcards are stored in plain arrays which are ...