Everything about UNIX kernels: development, configuration, compilation, design, etc.

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cannot upgrade kernel (grubby fatal error: unable to find a suitable template)

I have an appliance (read: a PC in a rackmount chassis which sits in the rack and does its job for years without anyone really paying it much attention until it dies) running CentOS 5.4. Trying to ...
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1answer
67 views

How do I detect that my system has auto-rebooted after a kernel panic?

I'm using Linux in embedded systems, and want to configure the system to automatically reboot after a kernel panic. However, when the system comes back up, it's important for me to detect and log the ...
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2answers
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Linux kernel parameter “net.ipv4.tcp_workaround_signed_windows”

I am seeing some intermittent network issues when sending large amounts of data over a network and it has been suggested to me that setting this option to a 1 may possibly resolve the issue. ...
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47 views

linux kernel module building prerequisites

The "How to Build External Modules" section of the kernel.org kbuild documentation ( https://www.kernel.org/doc/Documentation/kbuild/modules.txt ) says: To build external modules, you must have a ...
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56 views

Linux kernel: meaning of source-tree, in-tree and out-of-tree

What do the terms "in-tree" and "out-of-tree" exactly mean? Also, does "source tree" specifically refer to the official kernel released from / maintained at kernel.org or is it a more general term ...
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how to get 32 bit kernel headers in 64 bit debian jessie installation [duplicate]

aptitude search linux-headers provides this: p linux-headers-3.16.0-4-all - All header files for Linux 3.16 (meta-pack p linux-headers-3.16.0-4-all-amd6 - All header files for Linux 3.16 ...
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1answer
58 views

Difference in execution of init with embedded vs. external initramfs?

I'm building a very minimal linux system that just consists of the kernel (v4.1-rc5) and an initramfs populated with busybox (v1.23.2). It works fine for the most part, but I observe a difference in ...
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Why is the Linux kernel called an “image”?

I often hear people refer to the Linux kernel as the Linux kernel image and I can't seem to find an answers on any search engines as to why its called an image. When I think of an image I can only ...
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66 views

How can I prevent a module from flooding my kernel log with useless output?

I'm using the atmel_mxt_ts module, and it floods my kernel log with useless status messages, about 10 per second. I'm worried this will make my journal massive and cause unnecessary writes to my SSD. ...
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Is the Linux kernel affected by paging?

Is the whole kernel always loaded to RAM whatever the size of the RAM? In other words, can the Linux kernel be affected by paging (some part of kernel reside in virtual memory)?
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How to explain strange kernel messages?

I have a server running on Debian Wheezy 3.2.68-1+deb7u1 x86_64. Lately strange records in /var/log/messages appeared. First messages of this log starts just after server reboot. 6.222.18 LEN=44 ...
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How to debug freeze at start, output of syslog

Every now and then, my computer freezes while starting. I can see some "Oops" in /var/log/syslog, but from there I am not sure what to do to try and fix the problem. Jun 5 12:47:40 fulla kernel: [ ...
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264 views

how to make LVMs at available boot? kernel panic - dracut cannot find logical volumes after kernel upgrade in CentOS 6.6

I have a centoOS 6.6 vmware vm that I ran yum update on which upgraded the kernel after reboot, I started getting this: dracut Warning: No root device "block:/dev/vg_myhost/lv_root" found dracut ...
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Qemu Linux(kernel with debugging symbols) and ARM

I'm looking for a Linux ARM kernel, disk image and initrd that is compiled with debugging symbols. I'm looking to debug the kernel using the qemu and gdb. Could you point me to an arm linux image that ...
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92 views

Linux kernel patches: can I skip some?

I have the source of Linux 3.4.0 to which I added some modifications. I know that here (ftp://ftp.kernel.org/pub/linux/kernel/v3.x/) I can find all the 107 patches that need to be applied to my source ...
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System accounting misbehaviour on MacOS X (Yosemite)?

On all my Unixes (CentOS, FreeBSD, MacOS X) I activate the system accounting as a basic security rule. On MacOS X (Yosemite, 10.10.3) I see a misbehaviour I am investigating to fix. Everytime I run ...
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High read/write system call time

I am facing a weird problem with one of process taking more processing time in one system comparing to other systems. Most of the time is spending on read and write system call on problem host. I am ...
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Triggering hardware interrupts by connecting parallel port pins 9 and 10 does not work

I want to trigger hardware interrupts as described in the book Linux Device Drivers by connecting pins 9 and 10 with a wire. I tried that but apparently there's no interrupt beeing triggered: cat ...
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Book for understanding latest Linux kernel [closed]

I want to understand the Linux kernel. For this I have the book "UnderStanding the Linux Kernel, 3e". Inside the book I have found that the book has written based on Linux kernel 2.6. But as my ...
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What are the programs/commands which the magic SysRq key invoke?

From Magic SysRq key The magic SysRq key is a key combination understood by the Linux kernel, which allows the user to perform various low level commands regardless of the system's state. It ...
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449 views

How do you install the FreeBSD10 kernel sources?

I am trying to run an update of freebsd10 and I am being asked for the kernel sources ===>>> Launching child to update lsof-4.89.b,8 to lsof-4.89.d,8 ===>>> All >> ...
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110 views

Where is routing table stored internally in the Linux kernel?

When I execute route -n, from where exactly (from which structs) is the information displayed retrieved? I tried executing strace route -n but I didn't help me finding the right place it's stored.
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Why there is PPPd instead of all PPP software in kernel?

Are there any reasons why the need of PPP software separation from kernel and process (PPPd)?
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134 views

how to untar file in linux red hat?

I am compiling linux red hat stable kernel on red hat linux and the error which I am facing is as below
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1k views

Kernel Backport for Debian Jessie?

I installed the 32 bit version of Debian Jessie (8.0) on an Asus X205TA. The Asus X205TA laptop is quirky like a lot of Intel Baytrail Atom laptops/tablets in that it has 32 bit EFI but a 64 bit ...
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Using dkms to patch kernel

I need to apply a kernel patch(https://lkml.org/lkml/2015/3/31/929) to get my touch-pad working properly. I am thinking that I should be using dkms, to do this. Most of the stuff I am reading is about ...
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172 views

bdl_pos_adj: set IRQ timing workaround for hda-intel

I get following errors in my logs: kernel: snd_hda_intel 0000:00:1b.0: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj Google found some old posts here and ...
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41 views

Kernel modules for compiled kernel

I cannot find kernel-headers. For the first time I compiled and installed the latest kernel (4.0.3) on my Debian Wheezy, and now I am trying to install ndiswrapper using module assistant. For that, ...
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38 views

Why does user mode linux spawn 4 processes?

If I start User Mode Linux with this command: ./kernel32-3.19.8 ubda=./Debian-Wheezy-x86-root_fs mem=128m On Debian GNU/Linux 8 (jessie) with one CPU core, why do I see 4 processes in top: 1608 ...
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Linux Driver for USB “reverse” mass storage device

I'm developing a USB device that I want to read and write in virtual filesystems that are in my computer. Basically the device needs to be able to read, write and get the virtual filesystem size. Some ...
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134 views

Not able to reinstall the kernel or to use the latest version

On a ubuntu server, I try to di "sudo modprob" and I have this error : $ sudo depmod [sudo] password for deployer: depmod: ERROR: could not open directory /lib/modules/3.8.0-38-generic: No such file ...
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how to check a kernel version which was used when building package

I use apt when downloading packages from Ubuntu repositories. How can I check which kernel version was used when building package? When it is important (kernel version of the build server vs. kernel ...
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82 views

Downgrade Debian kernel

I have a requirement to install Debian kernel 3.2.65-1+deb7u2. I cannot seem to find the kernel. I have taken the following steps: Installed kernel 3.2.68-1+deb7u1. Downgraded the kernel to ...
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READ DMA Error after Installing CentOS 7

I have been trying to install CentOS7. After I installed it, I see the following message sporadically. ata2.00: exception Emask 0x10 SAct 0x0 SErr 0x4050000 action 0xe frozen ata2.00: irq_stat ...
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why do some network cards need to load external firmware?

I have read this question/answer, but I still do not understand why some network cards work perfectly well without any additional firmware, whereas others need to load firmware to work. As a specific ...
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1answer
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GNU\Linux clustreing , Which level? Which application? [closed]

I need to start GNU* clustering, But I have problem, Which level: DB level? (replication) file system? (distributed) process level ? (such as intel fortran for civilization softwares) new process ? ...
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Limit system processes using cgroups

My server runs several dozens of processes that are not in my control (mostly monitoring software). According to my application logs, sometimes some of the third party processes try to allocate too ...
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Uprobes Status on the present linux kernel

I know uprobes was introduced on kernel 3.5 has it survived or is it dropped, is it still available on kernel 4.x
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RHEL6 Idle Thread Behavior

I am doing some cpu performance profiling with the perf tool on a RHEL6 box running weblogic12g. It looks like the idle threads are presented as native_safe_halt in the stack profile but ...
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Filesytem errors during boot

I am using OMAPL138 and kernel version 2.6.37 and I would like to improve the boot time of my system. I made some progress on this, but I still have some errors which may be causing delay in the boot ...
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1k views

Centos 7.1 still using outdate kernel 3.10 how to upgrade to kernel 4.0

I'd like to upgrade my Centos 7.1 kernel from 3.10 to 4.0 i did successfully in Ubuntu 15.04 using Linux 4.0.1-040001-generic even though i updated it manually it's works fine so please could ...
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150 views

crypto kernel module not available on Raspberry pi 2 (linux 3.18.11)

I'm trying to use dm-crypt on my Raspberry Pi 2 with Raspbian (debian) to open a trueCrypt volume, but i get Required kernel crypto interface not available. Ensure you have algif_skcipher kernel ...
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Having problems with negative monitor channel, intimidated!

When I try this command: aireplay-ng -1 0 mon0 -a xx:xx:xx:xx:xx:xx I get this output: No source MAC (-h) specified. Using the device MAC (xx:xx:xx:xx:xx:xx) 17:51:23 Waiting for beacon frame ...
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Kernel problem after editing filesystem.squashfs

I use Kali Live linux (which is based on Debian), today I tried to edit filesystem.squashfs file which is located at /live/filesystem.squashfs using squashfs-tools. First I extracted this file using ...
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126 views

Relationship between IO scheduler and cpu/process scheduler?

The concepts of IO scheduler and CPU scheduler confuse me. Below are my understanding: Linux uses CFS scheduler + nice values by default to schedule processes. Each process has an IO queue. There ...
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179 views

Which file in /proc gets read by the kernel during the boot up process?

Which file in /proc gets read by the kernel during the boot up process? This was a question on my LPIC 101 test that I think I might have answered wrong. I searched on google and some other places but ...
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249 views

virtualbox can not create new virtual machine

I'm try to make a new virtual machine but virtualbox have this error in end step : Failed to create a new session. Callee RC: NS_ERROR_FACTORY_NOT_REGISTERED (0x80040154) and in terminal this shwn ...
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Continuety of driver support in linux kernel

I am an embedded GNU/Linux learner. I understand with the new Kernel, driver support for most added hardware is coming through Device Tree Structure (DTS). But I have found out that there are still ...
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647 views

What are the concepts of “kernel ring buffer”, “user level”, “log level”?

I often saw the words "kernel ring buffer", "user level", "log level" and some other words appear together. e.g. /var/log/dmesg Contains kernel ring buffer information. /var/log/kern.log ...
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848 views

Set default kernel in GRUB

How can I pick which kernel GRUB2 should load by default? I recently installed a the linux realtime kernel and now it loads by default. I'd like to load the regular one by default. So far I only ...